Systematic review of dietary intervention trials to lower blood total cholesterol in free-living subjects

Objectives: To estimate the efficacy of dietary advice to lower blood total cholesterol concentration in free-living subjects and to investigate the efficacy of different dietary recommendations. Design: Systematic overview of 19 randomised controlled trials including 28 comparisons. Subjects: Free-living subjects. Interventions: Individualised dietary advice to modify fat intake. Main outcome measure: Percentage difference in blood total cholesterol concentration between the intervention and control groups. Results: The percentage reduction in blood total cholesterol attributable to dietary advice after at least six months of intervention was 5.3% (95% confidence interval 4.7% to 5.9%). Including both short and long duration studies, the effect was 8.5% at 3 months and 5.5% at 12 months. Diets equivalent to the step 2 diet of the American Heart Association were of similar efficacy to diets that aimed to lower total fat intake or to raise the polyunsaturated to saturated fatty acid ratio. These diets were moderately more effective than the step 1 diet of the American Heart Association (6.1% v 3.0% reduction in blood total cholesterol concentration; P<0.0001). On the basis of reported food intake, the targets for dietary change were seldom achieved. The observed reductions in blood total cholesterol concentrations in the individual trials were consistent with those predicted from dietary intake on the basis of the Keys equation. Conclusions: Individualised dietary advice for reducing cholesterol concentration is modestly effective in free-living subjects. More intensive diets achieve a greater reduction in serum cholesterol concentration. Failure to comply fully with dietary recommendations is the likely explanation for this limited efficacy.

Key messages

• Results from metabolic ward studies suggest that dietary change can reduce blood cholesterol concentrations by up to 15%
• In free-living subjects the standard step 1 diet of the American Heart Association lowers cholesterol concentration by about 3%, and about another 3% can be achieved with more intensive diets
• Difficulties in complying with the prescribed dietary change explain the failure to achieve the expected reductions in cholesterol concentrations
• It is important to be realistic about the reductions in cardiovascular risk that can be achieved by individual dietary counselling

     

Prospective evaluation of folic acid supplementation on plasma homocysteine concentrations during weight reduction: a randomized, double-blinded, placebo-controlled study in obese women

Elevated total homocysteine concentrations and obesity are both associated with an increased risk of cardiovascular disease. However, previous studies of weight reduction on serum homocysteine concentrations have obtained inconsistent reports. We investigated the effect of folic acid supplementation on serum homocysteine concentrations via a randomized, double-blinded, placebo-controlled study. Seventy-four obese women [age (mean +/- SEM) 41 +/- 1 years; body mass index, 29.6 +/- 0.5 kgs/m2] completed a 12 weeks weight reduction program with dietary advice and light exercise. They were also randomized to take either folic acid supplementation (5 mg daily, n = 36) or placebo (n = 38) groups. This program led to a weight reduction of 7.7% and 8.9% of initial weight for folic acid supplementation and placebo groups, respectively. Serum folate concentrations increased for 3 folds (p < 0.001) in the folic acid group. In the folic acid group, there was a trend of lower fasting serum homocysteine concentrations (7.6 +/- 0.2 vs. 7.3 +/- 0.3 micromol/L), but it did not reach statistical significance (p = 0.170). However, we found that serum homocysteine concentrations decreased significantly in those with higher baseline homocysteine concentrations (8.7 +/- 1.3 vs. 7.8 +/- 1.5 micromol/L, p = 0.004), while it did not change in those with lower baseline homocysteine concentrations (6.6 +/- 0.6 vs. 6.8 +/- 1.2 micromol/L, p = 0.334). Reduction of serum homocysteine concentrations did not correlate with elevation of serum folate concentrations (p = 0.646) in obese women with higher baseline homocysteine concentrations. In conclusion, serum homocysteine concentrations can be maintained in obese women during mild to moderate weight loss. Folic acid supplementation decreased serum homocysteine concentrations in those women who had higher serum homocysteine concentrations before participating in the weight reduction program.     

Folate, homocysteine, endothelial function and cardiovascular disease

Evidence reported from numerous clinical studies over the past decade has revealed an association between increased plasma total homocysteine (tHcy) concentrations and cardiovascular disease (CVD). In addition, epidemiological studies have identified an inverse association between blood folate concentrations, folate intake and cardiovascular endpoints, that are independent of homocysteine. Folic acid supplementation can lower plasma tHcy concentrations safely and inexpensively. Furthermore, folic acid can reverse endothelial dysfunction observed in patients with CVD. This reversal in endothelial dysfunction with folic acid has been shown to be independent of plasma tHcy lowering, suggesting that folate has pleiotropic effects on the vasculature other than homocysteine lowering. In vitro evidence demonstrates that 5-methyltetrahydrofolate (5MeTHF) the main circulating metabolite of folate, can increase nitric oxide production and can directly scavenge superoxide radicals. The potential beneficial role of folic acid supplements on vascular disease are currently being tested in randomized placebo controlled studies.     

Screening of newborn infants for cholestatic hepatobiliary disease with tandem mass spectrometry

ObjectiveTo assess the feasibility of screening for cholestatic hepatobiliary disease and extrahepatic biliary atresia by using tandem mass spectrometry to measure conjugated bile acids in dried blood spots obtained from newborn infants at 7-10 days of age for the Guthrie test.SettingThree tertiary referral clinics and regional neonatal screening laboratories.DesignUnused blood spots from the Guthrie test were retrieved for infants presenting with cholestatic hepatobiliary disease and from the two cards stored on either side of each card from an index child. Concentrations of conjugated bile acids measured by tandem mass spectrometry in the two groups were compared.Results218 children with cholestatic hepatobiliary disease were eligible for inclusion in the study. Two children without a final diagnosis and five who presented at <14 days of age were excluded. Usable blood spots were obtained from 177 index children and 708 comparison children. Mean concentrations of all four bile acid species were significantly raised in children with cholestatic hepatobiliary disease and extrahepatic biliary atresia compared with the unaffected children (P<0.0001). Of 177 children with cholestatic hepatobiliary disease, 104 (59%) had a total bile acid concentration >33 μmol/l (97.5th centile value for comparison group). Of the 61 with extrahepatic biliary atresia, 47 (77%) had total bile acid concentrations >33 μmol/l. Taurotrihydroxycholanoate and total bile acid concentrations were the best predictors of both conditions. For all cholestatic hepatobiliary disease, a cut off level of total bile acid concentration of 30 μmol/l gave a sensitivity of 62% and a specificity of 96%, while the corresponding values for extrahepatic biliary atresia were 79% and 96%.ConclusionMost children who present with extrahepatic biliary atresia and other forms of cholestatic hepatobiliary disease have significantly raised concentrations of conjugated bile acids as measured by tandem mass spectrometry at the time when samples are taken for the Guthrie test. Unfortunately the separation between the concentrations in these infants and those in the general population is not sufficient to make mass screening for cholestatic hepatobiliary disease a feasible option with this method alone.

Key messages

• The prognosis of cholestatic hepatobiliary disease in infancy, in particular biliary atresia, is improved by early detection
• Infants destined to present with cholestatic jaundice in the first few months of life have raised concentrations of bile acids in the blood spots obtained at 7-10 days for current neonatal screening programmes
• Tandem mass spectrometry can be used to detect this marker of neonatal cholestasis
• Unfortunately there is too much overlap between bile acid concentrations in infants with cholestasis and those in control infants for this to be used as a single screening test for cholestatic hepatobiliary disease in general and biliary atresia
• Tandem mass spectrometry is a powerful tool for neonatal screening but every potential application must be carefully assessed

     

Tight blood pressure control and risk of macrovascular and microvascular complications in type 2 diabetes: UKPDS 38

Objective: To determine whether tight control of blood pressure prevents macrovascular and microvascular complications in patients with type 2 diabetes.Design: Randomised controlled trial comparing tight control of blood pressure aiming at a blood pressure of <150/85 mm Hg (with the use of an angiotensin converting enzyme inhibitor captopril or a β blocker atenolol as main treatment) with less tight control aiming at a blood pressure of <180/105 mm Hg.Setting: 20 hospital based clinics in England, Scotland, and Northern Ireland.Subjects: 1148 hypertensive patients with type 2 diabetes (mean age 56, mean blood pressure at entry 160/94 mm Hg); 758 patients were allocated to tight control of blood pressure and 390 patients to less tight control with a median follow up of 8.4 years.Main outcome measures: Predefined clinical end points, fatal and non-fatal, related to diabetes, deaths related to diabetes, and all cause mortality. Surrogate measures of microvascular disease included urinary albumin excretion and retinal photography.Results: Mean blood pressure during follow up was significantly reduced in the group assigned tight blood pressure control (144/82 mm Hg) compared with the group assigned to less tight control (154/87 mm Hg) (P<0.0001). Reductions in risk in the group assigned to tight control compared with that assigned to less tight control were 24% in diabetes related end points (95% confidence interval 8% to 38%) (P=0.0046), 32% in deaths related to diabetes (6% to 51%) (P=0.019), 44% in strokes (11% to 65%) (P=0.013), and 37% in microvascular end points (11% to 56%) (P=0.0092), predominantly owing to a reduced risk of retinal photocoagulation. There was a non-significant reduction in all cause mortality. After nine years of follow up the group assigned to tight blood pressure control also had a 34% reduction in risk in the proportion of patients with deterioration of retinopathy by two steps (99% confidence interval 11% to 50%) (P=0.0004) and a 47% reduced risk (7% to 70%) (P=0.004) of deterioration in visual acuity by three lines of the early treatment of diabetic retinopathy study (ETDRS) chart. After nine years of follow up 29% of patients in the group assigned to tight control required three or more treatments to lower blood pressure to achieve target blood pressures.Conclusion: Tight blood pressure control in patients with hypertension and type 2 diabetes achieves a clinically important reduction in the risk of deaths related to diabetes, complications related to diabetes, progression of diabetic retinopathy, and deterioration in visual acuity.

Key messages

• This study showed that tight control of blood pressure based on captopril or atenolol as first agents and aiming for both a systolic blood pressure <150 mm Hg and diastolic pressure <85 mm Hg achieved a mean 144/82 mm Hg compared with 154/87 mm Hg in a control group
• 29% of patients in the tight control group required three or more hypotensive treatments
• Tight control of blood pressure reduced the risk of any non-fatal or fatal diabetic complications and of death related to diabetes; deterioration in visual acuity was also reduced
• Reducing blood pressure needs to have high priority in caring for patients with type 2 diabetes

     

β Blockade after myocardial infarction: systematic review and meta regression analysis

ObjectivesTo assess the effectiveness of β blockers in short term treatment for acute myocardial infarction and in longer term secondary prevention; to examine predictive factors that may influence outcome and therefore choice of drug; and to examine the clinical importance of the results in the light of current treatment.DesignSystematic review of randomised controlled trials.SettingRandomised controlled trials.SubjectsPatients with acute or past myocardial infarction.Interventionβ Blockers compared with control.Mainoutcome measures All cause mortality and non-fatal reinfarction.ResultsOverall, 5477 of 54 234 patients (10.1%) randomised to β blockers or control died. We identified a 23% reduction in the odds of death in long term trials (95% confidence interval 15% to 31%), but only a 4% reduction in the odds of death in short term trials (−8% to 15%). Meta regression in long term trials did not identify a significant reduction in effectiveness in drugs with cardioselectivity but did identify a near significant trend towards decreased benefit in drugs with intrinsic sympathomimetic activity. Most evidence is available for propranolol, timolol, and metoprolol. In long term trials, the number needed to treat for 2 years to avoid a death is 42, which compares favourably with other treatments for patients with acute or past myocardial infarction.Conclusionsβ Blockers are effective in long term secondary prevention after myocardial infarction, but they are underused in such cases and lead to avoidable mortality and morbidity.

Key messages

• The first randomised trials of β blockade in secondary prevention after myocardial infarction were published in the 1960s
• β blockers were once heralded as a major advance, but their use for secondary prevention has declined in recent years
• Firm evidence shows that long term β blockade remains an effective and well tolerated treatment that reduces mortality and morbidity in unselected patients after myocardial infarction
• The benefits from β blockade compare favourably with other drug treatments for this patient group
• Most evidence is for propranolol, timolol, and metoprolol, whereas atenolol, which is commonly used, is inadequately evaluated for long term use

     

Effect of folate deficiency on placental DNA methylation in hyperhomocysteinemic rats

We report that the maternal folate status can influence folate-mediated one-carbon metabolism and DNA methylation in the placenta. Thirty-six female Sprague-Dawley rats were divided into the following three dietary groups: folate-supplemented (FS; 8 mg/kg folic acid, n=12), homocystine- and folate-supplemented (HFS; 0.3% homocystine and 8 mg/kg folic acid, n=12) and homocystine-supplemented and folate-deficient (HFD; 0.3% homocystine and no folic acid, n=12). The animals were fed their experimental diets from 4 weeks prior to mating until Day 20 of pregnancy (n=7-9 per group). The HFS diet increased the plasma homocysteine and placental DNA methylation but did not affect plasma folate, vitamin B-12, S-adenosyl methionine (SAM) or S-adenosyl homocysteine (SAH) levels, or the SAM/SAH ratio in the liver and placenta compared with the FS diet. The HFD diet induced severely low plasma folate concentrations, with plasma homocysteine levels increasing up to 100 micromol/L, and increased hepatic SAH and decreased placental SAM levels and SAM/SAH ratio in both tissues, with a concomitant decrease in placental DNA methylation. Placental DNA methylation was significantly correlated with placental (gamma=0.819), hepatic (gamma=0.7) and plasma (gamma=0.752) folate levels; plasma homocysteine level (gamma=-0.688); hepatic SAH level (gamma=-0.662) and hepatic SAM/SAH ratio (gamma=0.494). These results suggest that the maternal folate status in hyperhomocysteinemic rats influences the homeostasis of folate-mediated one-carbon metabolism and the methyl pool, which would, in turn, affect placental DNA methylation by altering the methylation potential of the liver.     

Cross sectional survey of effectiveness of lipid lowering drugs in reducing serum cholesterol concentration in patients in 17 general practices

ObjectiveTo compare the effectiveness of lipid lowering drugs in lowering serum cholesterol concentrations.DesignCross sectional study.Setting17 practices within 17 primary care groups in Trent region, United Kingdom.ParticipantsPatients aged 35 years or over taking lipid lowering drugs and with at least two serum cholesterol concentrations recorded on computer.Results1353 of 2469 (54.8%) patients receiving lipid lowering treatment had a last recorded serum cholesterol concentration of ⩽5 mmol/l. Significantly more patients taking statins achieved the target value for serum cholesterol (5 mmol/l) than those taking fibrates (1307 (57%) v 46 (26%); P<0.0001). Atorvastatin and simvastatin were the most effective drugs in achieving the target. Significant differences were found between lipid lowering drugs for the pretreatment serum cholesterol concentration, the most recent cholesterol concentration, and the associated percentage reduction. Atorvastatin and simvastatin achieved the greatest percentage reduction in serum cholesterol concentrations (30.1%, 95% confidence interval 28.8% to 31.4%, and 28.0%, 26.7% to 29.3%, respectively). Although the mean serum cholesterol concentrations in this unselected population tended to be higher than those in clinical trials, the percentage reduction was consistent with the trials.ConclusionThe ability of individual statins to lower serum cholesterol concentration varied, with atorvastatin and simvastatin being the most effective. The percentage reductions agreed with those of randomised controlled trials indicating likely benefits in unselected patients in primary care. As the initial serum cholesterol concentrations were higher than those in randomised controlled trials, target serum cholesterol values of ⩽5 mmol/l may be unrealistic even for patients taking the most efficacious drugs. Also, the higher initial levels could mean that the absolute reduction in cardiovascular risk in primary care patients is greater than thought.

What is already known on this topic

Statins in patients with coronary heart disease help reduce further cardiovascular events and improve survivalThis seems to be a class effect of statins, although there may be important differences in effectiveness between themLess than half of patients in the community who take lipid lowering drugs achieve target serum cholesterol values

What this study adds

Statins vary in their ability to lower serum cholesterol concentration, with atorvastatin and simvastatin achieving the best resultsThe percentage reductions agreed with those found in randomised controlled trialsSince the initial serum cholesterol concentrations were higher than in trials, absolute risk reductions in primary care patients may be greater than thoughtTarget values of ⩽5 mmol/l may be unrealistic even for patients on the most efficacious drugs, because the initial mean cholesterol values of primary care patients are higher than those of patients in trials     

Reporting on quality of life in randomised controlled trials: bibliographic study

ObjectivesTo examine the frequency and quality of reporting on quality of life in randomised controlled trials.DesignSearch of the Cochrane Controlled Trials Register 1980 to 1997 to identify trials from all disciplines, from oncology, and from cardiovascular medicine that reported on quality of life. Assessment of abstracts from articles published from 1993 to 1996. Assessment of a sample of full reports with a standardised instrument.ResultsDuring 1980-97 reporting on quality of life increased from 0.63% to 4.2% for trials from all disciplines, from 1.5% to 8.2% for cancer trials, and from 0.34% to 3.6% for cardiovascular trials. Of 364 abstracts, 65% reported on drug interventions. Of a sample of 67 full reports, authors of 48 (72%) used 62 established quality of life instruments. In 15 reports (22%) authors developed their own measures, and in 2 (3%) methods were unclear. Response rates were given in 38 (57%), and complete reporting on all items and scales occurred in 31 (46%).ConclusionsLess than 5% of all randomised controlled trials reported on quality of life, and this proportion was below 10% even for cancer trials. A plethora of instruments was used in different studies, and the reporting of methods and results was often inadequate. Standards for the measurement and reporting of quality of life in clinical trials research need to be developed.

Key messages

• We examined the reporting on quality of life in randomised controlled trials listed in the Cochrane Controlled Trials Register
• Although reporting on quality of life increased over time, fewer than 5% of trials overall and fewer than 10% of cancer trials included quality of life in 1997
• Among 67 articles selected at random for detailed examination, a wide range of established and self developed measures of quality of life were used
• Only about half of trials gave response rates, and less than half reported on all items and scales used
• Standards for assessing and reporting quality of life in clinical research trials need to be developed

     

Folate Catabolites in Spot Urine as Non-Invasive Biomarkers of Folate Status during Habitual Intake and Folic Acid Supplementation

Background

Folate status, as reflected by red blood cell (RCF) and plasma folates (PF), is related to health and disease risk. Folate degradation products para-aminobenzoylglutamate (pABG) and para-acetamidobenzoylglutamate (apABG) in 24 hour urine have recently been shown to correlate with blood folate.

Aim

Since blood sampling and collection of 24 hour urine are cumbersome, we investigated whether the determination of urinary folate catabolites in fasted spot urine is a suitable non-invasive biomarker for folate status in subjects before and during folic acid supplementation.

Study Design and Methods

Immediate effects of oral folic acid bolus intake on urinary folate catabolites were assessed in a short-term pre-study. In the main study we included 53 healthy men. Of these, 29 were selected for a 12 week folic acid supplementation (400 µg). Blood, 24 hour and spot urine were collected at baseline and after 6 and 12 weeks and PF, RCF, urinary apABG and pABG were determined.

Results

Intake of a 400 µg folic acid bolus resulted in immediate increase of urinary catabolites. In the main study pABG and apABG concentrations in spot urine correlated well with their excretion in 24 hour urine. In healthy men consuming habitual diet, pABG showed closer correlation with PF (r_s = 0.676) and RCF (r_s = 0.649) than apABG (r_s = 0.264, ns and 0.543). Supplementation led to significantly increased folate in plasma and red cells as well as elevated urinary folate catabolites, while only pABG correlated significantly with PF (r_s = 0.574) after 12 weeks.

Conclusion

Quantification of folate catabolites in fasted spot urine seems suitable as a non-invasive alternative to blood or 24 hour urine analysis for evaluation of folate status in populations consuming habitual diet. In non-steady-state conditions (folic acid supplementation) correlations between folate marker (RCF, PF, urinary catabolites) decrease due to differing kinetics.     

Homocysteine-Lowering by B Vitamins Slows the Rate of Accelerated Brain Atrophy in Mild Cognitive Impairment: A Randomized Controlled Trial

Background

An increased rate of brain atrophy is often observed in older subjects, in particular those who suffer from cognitive decline. Homocysteine is a risk factor for brain atrophy, cognitive impairment and dementia. Plasma concentrations of homocysteine can be lowered by dietary administration of B vitamins.

Objective

To determine whether supplementation with B vitamins that lower levels of plasma total homocysteine can slow the rate of brain atrophy in subjects with mild cognitive impairment in a randomised controlled trial (VITACOG, ISRCTN 94410159).

Methods and Findings

Single-center, randomized, double-blind controlled trial of high-dose folic acid, vitamins B₆ and B₁₂ in 271 individuals (of 646 screened) over 70 y old with mild cognitive impairment. A subset (187) volunteered to have cranial MRI scans at the start and finish of the study. Participants were randomly assigned to two groups of equal size, one treated with folic acid (0.8 mg/d), vitamin B₁₂ (0.5 mg/d) and vitamin B₆ (20 mg/d), the other with placebo; treatment was for 24 months. The main outcome measure was the change in the rate of atrophy of the whole brain assessed by serial volumetric MRI scans.

Results

A total of 168 participants (85 in active treatment group; 83 receiving placebo) completed the MRI section of the trial. The mean rate of brain atrophy per year was 0.76% [95% CI, 0.63–0.90] in the active treatment group and 1.08% [0.94–1.22] in the placebo group (P = 0.001). The treatment response was related to baseline homocysteine levels: the rate of atrophy in participants with homocysteine >13 µmol/L was 53% lower in the active treatment group (P = 0.001). A greater rate of atrophy was associated with a lower final cognitive test scores. There was no difference in serious adverse events according to treatment category.

Conclusions and Significance

The accelerated rate of brain atrophy in elderly with mild cognitive impairment can be slowed by treatment with homocysteine-lowering B vitamins. Sixteen percent of those over 70 y old have mild cognitive impairment and half of these develop Alzheimer''s disease. Since accelerated brain atrophy is a characteristic of subjects with mild cognitive impairment who convert to Alzheimer''s disease, trials are needed to see if the same treatment will delay the development of Alzheimer''s disease.

Trial Registration

Controlled-Trials.com ISRCTN94410159     

Symptomatic gastro-oesophageal reflux disease: double blind controlled study of intermittent treatment with omeprazole or ranitidine. The European Study Group

ObjectiveTo assess intermittent treatment over 12 months in patients with symptomatic gastro-oesophageal reflux disease.DesignRandomised, multicentre, double blind, controlled study. Patients with heartburn and normal endoscopy results or mild erosive changes received omeprazole 10 mg or 20 mg daily or ranitidine 150 mg twice daily for 2 weeks. Patients remaining symptomatic had omeprazole 10 mg or ranitidine dose doubled for another 2 weeks while omeprazole 20 mg was continued for 2 weeks. Patients who were symptomatic or mildly symptomatic were followed up for 12 months. Recurrences of moderate or severe heartburn during follow up were treated with the dose which was successful for initial symptom control.SettingHospitals and primary care practices between 1994 and 1996.Subjects677 patients with gastro-oesophageal reflux disease.Results704 patients were randomised, 677 were eligible for analyses; 318 reached the end of the study with intermittent treatment without recourse to maintenance antisecretory drugs. The median number of days off active treatment during follow up was 142 for the entire study (281 for the 526 patients who reached a treatment related end point). Thus, about half the patients did not require treatment for at least 6 months, and this was similar in all three treatment groups. According to outcome, 378 (72%) patients were in the best outcome ranks (no relapse or one (or more) relapse but in remission until 12 months); 630 (93%) had three or fewer relapses in the intermittent treatment phase. Omeprazole 20 mg provided faster relief of heartburn. The results were similar in patients with erosive and non-erosive disease.ConclusionsIntermittent treatment is effective in managing symptoms of heartburn in half of patients with uncomplicated gastro-oesophageal reflux disease. It is simple and applicable in general practice, where most patients are seen.

Key messages

• Symptomatic gastro-oesophageal disease can be managed successfully in half of patients with intermittent treatment with antisecretory drugs
• Omeprazole 20 mg once daily gives more rapid relief of symptoms than either omeprazole 10 mg once daily or ranitidine 150 mg twice daily. However, the choice of antisecretory drug has little effect on the overall outcome
• Relapses are relatively infrequent and can be managed with short courses of repeat treatment
• Starting intermittent treatment with omeprazole 20 mg once daily is more cost effective than a dose titration approach with omeprazole 10 mg once daily or ranitidine 150 mg twice daily
• An intermittent treatment strategy is simple and applicable in general practice, where most of these patients are seen

     

The Incidence and Prevention of Folate Deficiency in a Pregnant Clinic Population

Non-anemic women attending a public antenatal clinic were given, daily, a multivitamin tablet containing 78 mg. of elemental iron. The follow-up studies included an analysis of their diets. A total of 311 patients were included, of which one group received a supplement of 0.5 mg. folic acid and 0.005 mg. vitamin B₁₂. The incidence of megaloblastic bone marrow change in the unsupplemented group was 26% and of low blood folates approximately 50%. The incidence of megaloblastic changes was sharply reduced in the supplemented group and the blood folates were elevated to supranormal levels, indicating that the dose of folic acid used may have been above the minimal requirement. Formiminoglutamic acid (FIGLU) excretion could not be correlated with other parameters of folate deficiency. Neutrophil lobe counts did not relate to megaloblastic changes or low folate levels unless there was more than 5% hypersegmentation. The dietary intake was suboptimal in total calories, iron and food folate.     

Diagnosis of Creutzfeldt-Jakob disease by measurement of S100 protein in serum: prospective case-control study

Objective: To analyse serum concentrations of brain specific S100 protein in patients with Creutzfeldt-Jakob disease and in controls. Design: Prospective case-control study. Setting: National Creutzfeldt-Jakob disease surveillance unit. Subjects: 224 patients referred to the surveillance unit with suspected Creutzfeldt-Jakob disease and 35 control patients without dementia. Main outcome measure: Serum concentration of S100 protein in patients with Creutzfeldt-Jakob disease, in patients with other diseases causing dementia, and in the control group. Results: Of the 224 patients with suspected Creutzfeldt-Jakob disease, 65 were classed as definitely having the disease after neuropathological verification, an additional 6 were classed as definitely having the disease as a result of a genetic mutation, 43 as probably having the disease, 36 as possibly having the disease, and 74 patients were classed as having other disease. In the 108 patients classed as definitely or probably having Creutzfeldt-Jakob disease the median serum concentration of S100 was 395 pg/ml (SD 387 pg/ml). This was significantly higher than concentrations found in the 74 patients classed as having other diseases (median 109 pg/ml; SD 177 pg/ml; P=0.0001). At a cut off point of 213 pg/ml sensitivity for the diagnosis of the disease was 77.8% (95% confidence interval 68.8% to 85.2%) and specificity was 81.1% (70.3% to 89.3%). There was a significant difference in survival at different concentrations of S100 in Kaplan-Meier curves (P=0.023). Conclusion: Measurement of serum concentrations of S100 is a valuable tool which can be used more easily than tests on cerebrospinal fluid in the differential diagnosis of Creutzfeldt-Jakob disease. More studies are needed to determine whether serial testing of serum S100 improves diagnostic accuracy.

Key messages

• Creutzfeldt-Jakob disease is a rare, fatal neurodegenerative disease. Diagnosis is made clinically and neuropathologically
• There is no serum test which allows the diagnosis to be made while the patient is alive
• In this study raised serum concentrations of S100 protein were found in patients with Creutzfeldt-Jakob disease
• Serum concentrations of S100 could be used with a sensitivity of 77.8% and a specificity of 81.1% to confirm Creutzfeldt-Jakob disease in the differential diagnosis of diseases that cause dementia
• Serial measurement of S100 concentrations will enhance diagnostic accuracy

     

Twice daily versus four times daily insulin dose regimens for diabetes in pregnancy: randomised controlled trial

ObjectiveTo compare perinatal outcome and glycaemic control in two groups of pregnant diabetic patients receiving two insulin regimens.DesignRandomised controlled open label study.SettingUniversity affiliated hospital, Israel.Participants138 patients with gestational diabetes mellitus and 58 patients with pregestational diabetes mellitus received insulin four times daily, and 136 patients with gestational diabetes and 60 patients with pregestational diabetes received insulin twice daily.InterventionThree doses of regular insulin before meals and an intermediate insulin dose before bedtime (four times daily regimen), and a combination of regular and intermediate insulin in the morning and evening (twice daily regimen).ResultsMean daily insulin concentration before birth was higher in the women receiving insulin four times daily compared with twice daily: by 22 units (95% confidence interval 12 to 32) in patients with gestational diabetes and by 28 units (15 to 41) in patients with pregestational diabetes. Glycaemic control was better with the four times daily regimen than with the twice daily regimen: in patients with gestational diabetes mean blood glucose concentrations decreased by 0.19 mmol/l (0.13 to 0.25), HbA_1c by 0.3% (0.2% to 0.4%), and fructosamine by 41 μmol/l (37 to 45), and adequate glycaemic control (mean blood glucose concentration <5.8 mmol/l) was achieved in 17% (8% to 26%) more women; in patients with pregestational diabetes mean blood glucose concentration decreased by 0.44 mmol/l (0.28 to 0.60), HbA_1c by 0.5% (0.2% to 0.8%), and fructosamine by 51 μmol/l (45 to 57), and adequate glycaemic control was achieved in 31% (15% to 47%) more women. Maternal severe hypoglycaemic events, caesarean section, preterm birth, macrosomia, and low Apgar scores were similar in both dose groups. In women with gestational diabetes the four times daily regimen resulted in a lower rate of overall neonatal morbidity than the twice daily regimen (relative risk 0.59, 0.38 to 0.92), and the relative risk for hyperbilirubinaemia and hypoglycaemia was lower (0.51, 0.29 to 0.91 and 0.12, 0.02 to 0.97 respectively). The relative risk of hypoglycaemia in newborn infants to mothers with pregestational diabetes was 0.17 (0.04 to 0.74).ConclusionsGiving insulin four times rather than twice daily in pregnancy improved glycaemic control and perinatal outcome without further risking the mother.

Key messages

• Improving maternal glycaemic control during pregnancy is the key to better perinatal outcome
• In pregnant diabetic women insulin four times daily achieved better glycaemic control and lower rate of perinatal complications (hypoglycaemia, hyperbilirubinaemia) than insulin twice daily
• Better glycaemic control resulted from a larger total daily insulin dose
• The intensified regimen did not lead to higher rate of severe maternal hypoglycaemia

     

What is meant by intention to treat analysis? Survey of published randomised controlled trials

ObjectivesTo assess the methodological quality of intention to treat analysis as reported in randomised controlled trials in four large medical journals.DesignSurvey of all reports of randomised controlled trials published in 1997 in the BMJ, Lancet, JAMA, and New England Journal of Medicine.Results119 (48%) of the reports mentioned intention to treat analysis. Of these, 12 excluded any patients who did not start the allocated intervention and three did not analyse all randomised subjects as allocated. Five reports explicitly stated that there were no deviations from random allocation. The remaining 99 reports seemed to analyse according to random allocation, but only 34 of these explicitly stated this. 89 (75%) trials had some missing data on the primary outcome variable. The methods used to deal with this were generally inadequate, potentially leading to a biased treatment effect. 29 (24%) trials had more than 10% of responses missing for the primary outcome, the methods of handling the missing responses were similar in this subset.ConclusionsThe intention to treat approach is often inadequately described and inadequately applied. Authors should explicitly describe the handling of deviations from randomised allocation and missing responses and discuss the potential effect of any missing response. Readers should critically assess the validity of reported intention to treat analyses.

Key messages

• Intention to treat gives a pragmatic estimate of the benefit of a change in treatment policy rather than of potential benefit in patients who receive treatment exactly as planned
• Full application of intention to treat is possible only when complete outcome data are available for all randomised subjects
• About half of all published reports of randomised controlled trials stated that intention to treat was used, but handling of deviations from randomised allocation varied widely
• Many trials had some missing data on the primary outcome variable, and methods used to deal with this were generally inadequate, potentially leading to bias
• Intention to treat analyses are often inadequately described and inadequately applied

     

Human albumin administration in critically ill patients: systematic review of randomised controlled trials

Objective: To quantify effect on mortality of administering human albumin or plasma protein fraction during management of critically ill patients. Design: Systematic review of randomised controlled trials comparing administration of albumin or plasma protein fraction with no administration or with administration of crystalloid solution in critically ill patients with hypovolaemia, burns, or hypoalbuminaemia. Subjects: 30 randomised controlled trials including 1419 randomised patients. Main outcome measure: Mortality from all causes at end of follow up for each trial. Results: For each patient category the risk of death in the albumin treated group was higher than in the comparison group. For hypovolaemia the relative risk of death after albumin administration was 1.46 (95% confidence interval 0.97 to 2.22), for burns the relative risk was 2.40 (1.11 to 5.19), and for hypoalbuminaemia it was 1.69 (1.07 to 2.67). Pooled relative risk of death with albumin administration was 1.68 (1.26 to 2.23). Pooled difference in the risk of death with albumin was 6% (95% confidence interval 3% to 9%) with a fixed effects model. These data suggest that for every 17 critically ill patients treated with albumin there is one additional death. Conclusions: There is no evidence that albumin administration reduces mortality in critically ill patients with hypovolaemia, burns, or hypoalbuminaemia and a strong suggestion that it may increase mortality. These data suggest that use of human albumin in critically ill patients should be urgently reviewed and that it should not be used outside the context of rigorously conducted, randomised controlled trials.

Key messages

• Human albumin solution has been used in the treatment of critically ill patients for over 50 years
• Currently, the licensed indications for use of albumin are emergency treatment of shock, acute management of burns, and clinical situations associated with hypoproteinaemia
• Our systematic review of randomised controlled trials showed that, for each of these patient categories, the risk of death in the albumin treated group was higher than in the comparison group
• The pooled relative risk of death with albumin was 1.68 (95% confidence interval 1.26 to 2.23) and the pooled difference in the risk of death was 6% (3% to 9%) or six additional deaths for every 100 patients treated
• We consider that use of human albumin solution in critically ill patients should be urgently reviewed

     

Effect of genetic polymorphisms involved in folate metabolism on the concentration of serum folate and plasma total homocysteine (p-tHcy) in healthy subjects after short-term folic acid supplementation: a randomized,double blind,crossover study

Data on the effect of combined genetic polymorphisms, involved in folate metabolism, on the concentration of serum folate after folic acid supplementation are scarce. Therefore, we investigated the impact of seven gene polymorphisms on the concentration of serum folate and p-tHcy in healthy subjects after short-term folic acid supplementation. In a randomized, double blind, crossover study, apparently healthy subjects were given either 0.8 mg folic acid per day (n = 46) or placebo (n = 45) for 14 days. The washout period was 14 days. Fasting blood samples were collected on day 1, 15, 30 and 45. Data on subjects on folic acid supplementation (n = 91) and on placebo (n = 45) were used for the statistical analysis. The concentration of serum folate increased higher in subjects with higher age (53.5 ± 7.0 years) than in subjects with lower age (24.3 ± 3.2 years) after folic acid supplementation (p = 0.006). The baseline concentration of serum folate in subjects with polymorphism combination, reduced folate carrier protein, RFC1-80 GA and methylenetetrahydrofolate reductase, MTHFR677 CT+TT, was lower than RFC1-80 AA and MTHFR677 CT+TT (p = 0.002). After folic acid supplementation, a higher increase in the concentration of serum folate was detected in subjects with polymorphism combination RFC1-80 GA and MTHFR677 CC than RFC1-80 GG and MTHFR CT+TT combination (p < 0.0001). The baseline concentration of plasma total homocysteine (p-tHcy) was altered by combined polymorphisms in genes associated with folate metabolism. After folic acid supplementation, in subjects with combined polymorphisms in methylenetetrahydrofolate dehydrogenase, MTHFD1-1958 and MTHFR-677 genes, the concentration of p-tHcy was changed (p = 0.002). The combination of RFC1-80 and MTHFR-677 polymorphisms had a profound affect on the concentration of serum folate in healthy subjects before and after folic acid supplementation.