Midline episiotomy and anal incontinence: retrospective cohort study

ObjectiveTo evaluate the relation between midline episiotomy and postpartum anal incontinence.DesignRetrospective cohort study with three study arms and six months of follow up.SettingUniversity teaching hospital.ParticipantsPrimiparous women who vaginally delivered a live full term, singleton baby between 1 August 1996 and 8 February 1997: 209 who received an episiotomy; 206 who did not receive an episiotomy but experienced a second, third, or fourth degree spontaneous perineal laceration; and 211 who experienced either no laceration or a first degree perineal laceration.ResultsWomen who had episiotomies had a higher risk of faecal incontinence at three (odds ratio 5.5, 95% confidence interval 1.8 to 16.2) and six (3.7, 0.9 to 15.6) months postpartum compared with women with an intact perineum. Compared with women with a spontaneous laceration, episiotomy tripled the risk of faecal incontinence at three months (95% confidence interval 1.3 to 7.9) and six months (0.7 to 11.2) postpartum, and doubled the risk of flatus incontinence at three months (1.3 to 3.4) and six months (1.2 to 3.7) postpartum. A non-extending episiotomy (that is, second degree surgical incision) tripled the risk of faecal incontinence (1.1 to 9.0) and nearly doubled the risk of flatus incontinence (1.0 to 3.0) at three months postpartum compared with women who had a second degree spontaneous tear. The effect of episiotomy was independent of maternal age, infant birth weight, duration of second stage of labour, use of obstetric instrumentation during delivery, and complications of labour. ConclusionsMidline episiotomy is not effective in protecting the perineum and sphincters during childbirth and may impair anal continence.     

Changes in the management of labour: 2. Perineal management.

An analysis of 24,439 deliveries between 1980 and 1984 in a large British obstetric unit showed a striking decline in the rate of episiotomy. The rates of first- and second-degree perineal tears increased during the study period, but overall there was a significant rise in the proportion of women who gave birth with an intact perineum (p less than 0.001). There was no increase in the rate of third-degree tears or of other perineal complications. Delivery with an intact perineum was more likely among younger women, those with a short second stage of labour and those with a small baby (p less than 0.001). These findings confirm the short-term safety of lowering episiotomy rates and should be helpful to all obstetric professionals in reducing unnecessary perineal morbidity among childbearing women.     

Association of systolic blood pressure with macrovascular and microvascular complications of type 2 diabetes (UKPDS 36): prospective observational study

ObjectiveTo determine the relation between systolic blood pressure over time and the risk of macrovascular or microvascular complications in patients with type 2 diabetes.DesignProspective observational study.Setting23 hospital based clinics in England, Scotland, and Northern Ireland.Participants4801 white, Asian Indian, and Afro-Caribbean UKPDS patients, whether randomised or not to treatment, were included in analyses of incidence; of these, 3642 were included in analyses of relative risk.ResultsThe incidence of clinical complications was significantly associated with systolic blood pressure, except for cataract extraction. Each 10 mm Hg decrease in updated mean systolic blood pressure was associated with reductions in risk of 12% for any complication related to diabetes (95% confidence interval 10% to 14%, P<0.0001), 15% for deaths related to diabetes (12% to 18%, P<0.0001), 11% for myocardial infarction (7% to 14%, P<0.0001), and 13% for microvascular complications (10% to 16%, P<0.0001). No threshold of risk was observed for any end point.ConclusionsIn patients with type 2 diabetes the risk of diabetic complications was strongly associated with raised blood pressure. Any reduction in blood pressure is likely to reduce the risk of complications, with the lowest risk being in those with systolic blood pressure less than 120 mm Hg.     

Coronary and cardiovascular risk estimation for primary prevention: validation of a new Sheffield table in the 1995 Scottish health survey population

ObjectiveTo examine the accuracy of a new version of the Sheffield table designed to aid decisions on lipids screening and detect thresholds for risk of coronary heart disease needed to implement current guidelines for primary prevention of cardiovascular disease.DesignComparison of decisions made on the basis of the table with absolute risk of coronary heart disease or cardiovascular disease calculated by the Framingham risk function. The decisions related to statin treatment when coronary risk is ⩾30% over 10 years; aspirin treatment when the risk is ⩾15% over 10 years; and the treatment of mild hypertension when the cardiovascular risk is ⩾20% over 10 years.SettingThe table is designed for use in general practice.SubjectsRandom sample of 1000 people aged 35-64 years from the 1995 Scottish health survey.Results13% of people had a coronary risk of ⩾15%, and 2.2% a risk of ⩾30%, over 10 years. 22% had mild hypertension (systolic blood pressure 140-159 mm Hg). The table indicated lipids screening for everyone with a coronary risk of ⩾15% over 10 years, for 95% of people with a ratio of total cholesterol to high density lipoprotein cholesterol of ⩾8.0, but for <50% with a coronary risk of <5% over 10 years. Sensitivity and specificity were 97% and 95% respectively for a coronary risk of ⩾15% over 10 years; 82% and 99% for a coronary risk of ⩾30% over 10 years; and 88% and 90% for a cardiovascular risk of ⩾20% over 10 years in mild hypertension.ConclusionThe table identifies all high risk people for lipids screening, reduces screening of low risk people by more than half, and ensures that treatments are prescribed appropriately to those at high risk, while avoiding inappropriate treatment of people at low risk.     

Maternal and paternal age at delivery, birth order, and risk of childhood onset type 1 diabetes: population based cohort study

ObjectiveTo estimate the associations of maternal and paternal age at delivery and of birth order with the risk of childhood onset type 1 diabetes.DesignCohort study by record linkage of the medical birth registry and the national childhood diabetes registry in Norway.SettingNorway.SubjectsAll live births in Norway between 1974 and 1998 (1.4 million people) were followed for a maximum of 15 years, contributing 8.2 million person years of observation during 1989-98. 1824 cases of type 1 diabetes diagnosed between 1989 and 1998 were identified.ResultsThere was no association between maternal age at delivery and type 1 diabetes among firstborn children, but among fourthborn children there was a 43.2% increase in incidence of diabetes for each five year increase in maternal age (95% confidence interval 6.4% to 92.6%). Each increase in birth order was associated with a 17.9% reduction in incidence (3.2% to 30.4%) when maternal age was 20-24 years, but the association was weaker when maternal age was 30 years or more. Paternal age was not associated with type 1 diabetes after maternal age was adjusted for.ConclusionsIntrauterine factors and early life environment may influence the risk of type 1 diabetes. The relation of maternal age and birth order to risk of type 1 diabetes is complex.

What is already known on this topic

Maternal age at birth is positively associated with risk of childhood onset type 1 diabetesStudies of the effect of birth order on risk of type 1 diabetes have given inconsistent results

What does this study add?

In a national cohort, risk of diabetes in firstborn children was not associated with maternal ageIncreasing maternal age was a risk factor in children born second or laterThe strength of the association increased with increasing birth order     

The psychosocial impact of bilateral prophylactic mastectomy: prospective study using questionnaires and semistructured interviews

ObjectivesTo investigate the psychosocial impact of bilateral prophylactic mastectomy for women with increased risk of breast cancer and to identify, preoperatively, risk factors for postoperative distress.DesignProspective study using interviews and questionnaire assessments.SettingParticipants'' homes throughout the United Kingdom.Participants143 women with increased risk of developing breast cancer who were offered bilateral prophylactic mastectomy and who accepted or declined the surgery; a further 11 were offered surgery but deferred making a decision.ResultsPsychological morbidity decreased significantly over time for the 79 women who chose to have surgery (accepters): 58% (41/71) preoperatively v 41% (29/71) 6 months postoperatively (difference in percentages 17%, 95% confidence interval 2% to 32%; P=0.04) and 60% (39/65) preoperatively v 29% (19/65) 18 months postoperatively (31%, 15% to 47%; P<0.001). Psychological morbidity in the 64 women who declined surgery (decliners) did not decrease significantly: 57% (31/54) at baseline v 43% (23/54) at 6 months (14%, 0% to 29%; P=0.08) and 57% (29/52) at baseline v 41% (21/52) at 18 months (16%; −2% to 33%; P=0.11). Greater than normal proneness to anxiety was more common in the decliners than in the accepters: 78% (45/58) v 56% (41/73) (22%, 6% to 38%; P=0.006). Accepters were more likely than decliners to believe it inevitable that they would develop breast cancer (32% (24/74) v 10% (6/58) (difference in percentages 22%, 9% to 35%; P=0.003)), and decliners were more likely to believe that screening could help (92% (55/60) v 74% (55/74) (18%, 5% to 31%; P=0.007)). Level of sexual discomfort and degree of sexual pleasure did not change significantly over time in either of the two groups.ConclusionsBilateral prophylactic mastectomy may provide psychological benefits in women with a high risk of developing breast cancer.     

Physicians' beliefs and behaviour during a randomized controlled trial of episiotomy: consequences for women in their care.

OBJECTIVE: To evaluate whether physicians'' beliefs concerning episiotomy are related to their use of procedures and to differential outcomes in childbirth. DESIGN: Post-hoc cohort analysis of physicians and patients involved in a randomized controlled trial of episiotomy. SETTING: Two tertiary care hospitals and one community hospital in Montreal. PARTICIPANTS: Of the 703 women at low risk of medical or obstetric problems enrolled in the trial we studied 447 women (226 primiparous and 221 multiparous) attended by 43 physicians. Subjects attended by residents or nurses were excluded. MAIN OUTCOME MEASURES: Patients: intact perineum v. perineal trauma, length of labour, procedures used (instrumental delivery, oxytocin augmentation of labour, cesarean section and episiotomy), position for birth, rate of and reasons for not assigning women to a study arm, postpartum perineal pain and satisfaction with the birth experience, physicians: beliefs concerning episiotomy. RESULTS: Women attended by physicians who viewed episiotomy very unfavorably were more likely than women attended by the other physicians to have an intact perineum (23% v. 11% to 13%, p < 0.05) and to experience less perineal trauma. The first stage of labour was 2.3 to 3.5 hours shorter for women attended by physicians who viewed episiotomy favourably than for women attended by physicians who viewed episiotomy very unfavorably (p < 0.05 to < 0.01), and the former physicians were more likely to use oxytocin augmentation of labour. Physicians who viewed episiotomy more favourably failed more often than those who viewed the procedure very unfavourably to assign patients to a study arm late in labour (odds ratio [OR] 1.88, p < 0.05), both overall and because they felt that "fetal distress" or cesarean section necessitated exclusion of the subject. They used the lithotomy position for birth more often (OR 3.94 to 4.55, p < 0.001), had difficulty limiting episiotomy in the restricted-use arm of the trial and diagnosed fetal distress and perineal inadequacy more often than the comparison groups. The patients of physicians who viewed episiotomy very favourably experienced more perineal pain (p < 0.01), and of those who viewed episiotomy favourably and very favourably experienced less satisfaction with the birth experience (p < 0.01) than the patients of physicians who viewed the procedure very unfavourably. CONCLUSIONS: Physicians with favourably views of episiotomy were more likely to use techniques to expedite labour, and their patients were more likely to have perineal trauma and to be less satisfied with the birth experience. This evidence that physician beliefs can influence patient outcomes has both clinical and research implications.     

Reduction in mortality after inappropriate early discharge from intensive care unit: logistic regression triage model

ObjectiveTo develop a predictive model to triage patients for discharge from intensive care units to reduce mortality after discharge.DesignLogistic regression analyses and modelling of data from patients who were discharged from intensive care units.SettingGuy''s hospital intensive care unit and 19 other UK intensive care units from 1989 to 1998.Participants5475 patients for the development of the model and 8449 for validation.ResultsMortality after discharge from intensive care was up to 12.4%. The triage model identified patients at risk from death on the ward with a sensitivity of 65.5% and specificity of 87.6%, and an area under the receiver operating curve of 0.86. Variables in the model were age, end stage disease, length of stay in unit, cardiothoracic surgery, and physiology. In the validation dataset the 34% of the patients identified as at risk had a discharge mortality of 25% compared with a 4% mortality among those not at risk.ConclusionsThe discharge mortality of at risk patients may be reduced by 39% if they remain in intensive care units for another 48 hours. The discharge triage model to identify patients at risk from too early and inappropriate discharge from intensive care may help doctors to make the difficult clinical decision of whom to discharge to make room for a patient requiring urgent admission to the unit. If confirmed, this study has implications on the provision of resources.

What is already known on this topic

In the United Kingdom, the mortality of patients who die on the ward after discharge from intensive care is unacceptably high (9% to 27%)Indirect evidence has shown that this is due to too early and inappropriate discharge from intensive care that has increased over the past 10 years

What this study adds

A triage model identifies patients at risk from inappropriate discharge from intensive careMortality after discharge from intensive care may be reduced by 39% if these patients were to stay in intensive care for another 48 hoursAn estimated 16% more beds are required if mortality after discharge from intensive care is to be reduced     

Endpiece: The noble profession

ObjectivesTo assess whether bacterial vaginosis or chlamydial infection before 10 weeks'' gestation is associated with miscarriage before 16 weeks.DesignProspective cohort study.Setting32 general practices and five family planning clinics in south London.Participants1216 pregnant women, mean age 31, presenting before 10 weeks'' gestation.Results121 of 1214 women (10.0%, 95% confidence interval 8.3% to 11.7%) miscarried before 16 weeks. 174 of 1201 women (14.5%, 12.5% to 16.5%) had bacterial vaginosis. Compared with women who were negative for bacterial vaginosis those who were positive had a relative risk of miscarriage before 16 weeks'' gestation of 1.2 (0.7 to 1.9). Bacterial vaginosis was, however, associated with miscarriage in the second trimester at 13-15 weeks (3.5, 1.2 to 10.3). Only 29 women (2.4%, 1.5% to 3.3%) had chlamydial infection, of whom one miscarried (0.32, 0.04 to 2.30).ConclusionBacterial vaginosis is not strongly predictive of early miscarriage but may be a predictor after 13 weeks'' gestation. The prevalence of Chlamydia was too low to assess the risk, but it is unlikely to be a major risk factor in pregnant women.

What is already known on this topic

Miscarriages are common and associated with considerable morbidity and costsBacterial vaginosis is associated with miscarriage after 16 weeks'' gestation and preterm birth but the role of chlamydial infection is uncertain

What this study adds

Bacterial vaginosis is not a strong predictor of miscarriage before 16 weeks'' gestation but may be associated with miscarriage at 13-15 weeks'' gestationThe prevalence of chlamydial infection was too low for it to be a major risk factor for miscarriage in this population of healthy pregnant womenNon-invasive screening for bacterial vaginosis and chlamydial infection by using self administered vaginal swabs is feasible in pregnant women in the community     

Screening for diabetes in general practice: cross sectional population study

ObjectiveTo assess the policy proposed by the American Diabetes Association of universal screening in general practice of all patients aged over 45 years for diabetes.Design Cross sectional population study.Setting Local general practice in the United Kingdom.Participants All patients aged over 45 not known to have diabetes.Results Of 2481 patients aged over 45 and not known to have diabetes, 876 attended for screening. There were no significant demographic differences between the screened and unscreened patients. Prevalence of diabetes in patients with age as a sole risk factor was 0.2% (95% confidence interval 0% to 1.4%). Prevalence of diabetes in patients with age and one or more other risk factors (hypertension, obesity, or a family history of diabetes) was 2.8% (1.6% to 4.7%). Four hours a week for a year would be needed to screen all people over 45 in the practice''s population; about half this time would be needed to screen patients with risk factors other than age. More than 80% of patients newly diagnosed as having diabetes had a 10 year risk of coronary heart disease >15%, 73% (45% to 92%) were hypertensive, and 73% (45% to 92%) had a cholesterol concentration >5 mmol/l.Conclusions Screening for diabetes in general practice by measuring fasting blood glucose is feasible but has a very low yield in patients whose sole risk factor for diabetes is age over 45. Screening in a low risk population would best be targeted at patients with multiple risk factors.

What is already known on this topic

Between a third and a half of cases of diabetes are undiagnosed at any one timeNew cases can be identified by screening groups of patients at riskThe American Diabetes Association has proposed the screening of all patients aged over 45 every three years

What this study adds

Screening for diabetes in general practice by measuring fasting blood glucose is feasible but requires much staff timeScreening solely on the basis of age has a very low yield and screening would best be targeted at patients with multiple risk factors for diabetes     

Second dose of measles, mumps, and rubella vaccine: questionnaire survey of health professionals

ObjectiveTo determine the knowledge, attitudes, and practices among health professionals regarding the measles, mumps, and rubella (MMR) vaccine, particularly the second dose.Design Self administered postal questionnaire survey.Setting North Wales Health Authority, 1998.Participants 148 health visitors, 239 practice nurses, and 206 general practitioners.Results Concerning the second dose of the vaccine, 48% of the professionals (220/460) had reservations and 3% (15) disagreed with the policy of giving it. Over half the professionals nominated health visitors as the best initial source of advice on the second vaccine. 61% of health visitors (86/140), compared with 46% of general practitioners (73/158), reported feeling very confident about explaining the rationale of a two dose schedule to a well informed parent, but only 20% (28/138) would unequivocally recommend the second dose to a wavering parent. 33% of the practice nurses (54/163) stated that the MMR vaccine was very likely or possibly associated with Crohn''s disease and 27% (44/164) that it was associated with autism. Nearly a fifth of general practitioners (27/158) reported that they had not read the MMR section in the “green book,” and 29% (44/152) reported that they had not received the Health Education Authority''s factsheet on MMR immunisation.Conclusions Knowledge and practice among health professionals regarding the second dose of the MMR vaccine vary widely. Many professionals are not aware of or do not use the good written resources that exist, though local educational initiatives could remedy this.     

Methods and consequences of changes in use of episiotomy.

OBJECTIVES--To evaluate the use of feedback by graphical profiles of rates of episiotomy and the impact on clinical practice and perineal state after spontaneous vaginal deliveries assisted by midwives with different attitudes towards episiotomy. DESIGN--Observation period in labour ward followed by feedback to midwives about their own and other midwives'' use of episiotomies. The periods before and after the intervention were compared. SUBJECTS--All women (n = 3919) delivering during the two periods who had been assisted by one of 30 midwives; each midwife supervised at least 20 deliveries during each period. MAIN OUTCOME MEASURES--Overall rates of episiotomies and indications, incidence of intact perineums, perineal lacerations, and tears of anal sphincter. RESULTS--The overall rate of episiotomy during the observation period was 37.1% (615). During the second period the rate was 6.6% lower (95% confidence interval 3.6% to 9.6%), corresponding to a relative decrease of 17.8% (10.1% to 24.7%). Higher rates of episiotomy during the observation period were associated with larger reductions in the second period. The decrease could be explained by less use of episiotomy in deliveries with rigid perineum or impending perineal tear. Compared with the observation period, in the second period 3.2% more women (0.3% to 6.3%) had an intact perineum after delivery and 3.4% (0.4% to 6.2%) experienced perineal tears. The overall incidence of tears of the anal sphincter remained unchanged. Women had a slightly reduced incidence of tears of the anal sphincter, however, if they were delivered by midwives who reduced a medium or high initial rate of episiotomy and a tendency towards an increased incidence of tears if they were assisted by midwives who reduced low initial rates (around 20%) of episiotomy. CONCLUSIONS--Changes in the use of episiotomy induced by awareness of clinical practice among midwives seem to increase the incidence of parturients with intact perineum without a concomitant rise in tears of the anal sphincter. To avoid the increase of such tears these changes should probably be restricted to midwives with rates of episiotomies above 30%.     

Women's understanding of a "normal smear test result": experimental questionnaire based study

ObjectivesTo describe women''s understanding of a negative smear test result when presented using the term “normal smear result,” as required by the NHS cervical screening programme, and to evaluate the impact on understanding of different ways of presenting the residual risk inherent in such a result.DesignExperimental questionnaire based study.InterventionsParticipants were asked to imagine that they had received a normal smear result. The meaning of this result was then presented using different combinations of three different expressions of residual risk of having or developing cervical cancer over the next five years: a verbal probability of absolute risk (low risk), a numerical probability of absolute risk (1 in 5000), or a numerical probability of risk relative to an unscreened woman (five times lower).Participants1027 women aged 20 to 64.ResultsWhen informed only that their smear result was normal, 52% (80 of 153 women) of participants correctly understood that this entailed a residual risk of cervical cancer, compared with 70% (107 of 152) given the additional sentence explaining the meaning of a normal smear result using a verbal probability of absolute risk (difference 18%; 95% confidence interval 7% to 29%). Additionally, explaining the results using a numerical probability of absolute or relative risk did not increase the proportion who correctly understood that there was a residual risk of cervical cancer.ConclusionsNHS policy for reporting normal smears needs to change to make it a definite requirement that the reporting of a “normal smear result” is accompanied by a sentence stating that this means a low risk for having or developing cervical cancer in the next five years.     

Reanalysis of epidemiological evidence on lung cancer and passive smoking

ObjectiveTo assess the epidemiological evidence for an increase in the risk of lung cancer resulting from exposure to environmental tobacco smoke.DesignReanalysis of 37 published epidemiological studies previously included in a meta-analysis allowing for the possibility of publication bias.ResultsIf it is assumed that all studies that have ever been carried out are included, or that those selected for review are truly representative of all such studies, then the estimated excess risk of lung cancer is 24%, as previously reported (95% confidence interval 13% to 36%, P<0.001). However, a significant correlation between study outcome and study size suggests the presence of publication bias. Adjustment for such bias implies that the risk has been overestimated. For example, if only 60% of studies have been included, the estimate of excess risk falls from 24% to 15%.ConclusionA modest degree of publication bias leads to a substantial reduction in the relative risk and to a weaker level of significance, suggesting that the published estimate of the increased risk of lung cancer associated with environmental tobacco smoke needs to be interpreted with caution.

Key messages

• A systematic review of epidemiological studies on passive smoking estimated the increased risk of lung cancer as 24%
• There is clear evidence of publication bias in these studies
• Reanalysis of the data allowing for the possibility of publication bias substantially lowers the estimate of relative risk

     

Birth order,gestational age,and risk of delivery related perinatal death in twins: retrospective cohort study

ObjectiveTo determine whether twins born second are at increased risk of perinatal death because of complications during labour and delivery.DesignRetrospective cohort study.SettingScotland, 1992 and 1997.ParticipantsAll twin births at or after 24 weeks'' gestation, excluding twin pairs in which either twin died before labour or delivery or died during or after labour and delivery because of congenital abnormality, non-immune hydrops, or twin to twin transfusion syndrome.ResultsOverall, delivery related perinatal deaths were recorded for 23 first twins only and 23 second twins only of 1438 twin pairs born before 36 weeks (preterm) by means other than planned caesarean section (P>0.99). No deaths of first twins and nine deaths of second twins (P=0.004) were recorded among the 2436 twin pairs born at or after 36 weeks (term). Discordance between first and second twins differed significantly in preterm and term births (P=0.007). Seven of nine deaths of second twins at term were due to anoxia during the birth (2.9 (95% confidence interval 1.2 to 5.9) per 1000); five of these deaths were associated with mechanical problems with the second delivery following vaginal delivery of the first twin. No deaths were recorded among 454 second twins delivered at term by planned caesarean section.ConclusionsSecond twins born at term are at higher risk than first twins of death due to complications of delivery. Previous studies may not have shown an increased risk because of inadequate categorisation of deaths, lack of statistical power, inappropriate analyses, and pooling of data about preterm births and term births.

What is already known on this topic

It is difficult to assess the wellbeing of second twins during labourDeliveries of second twins are at increased risk of mechanical problems, such as cord prolapse and malpresentation, after vaginal delivery of first twinsIncreased risks of perinatal death in second twins have not been shown, but the methods of these studies were flawed

What this study adds

Second twins delivered at term are at increased risk of delivery related perinatal deathsIntrapartum anoxia caused 75% of these deaths in second twins, and most of these resulted from mechanical problems after vaginal delivery of first twinsPlanned caesarean section of twins at term may prevent perinatal deaths     

Using thresholds based on risk of cardiovascular disease to target treatment for hypertension: modelling events averted and number treated

ObjectiveTo estimate the impact of using thresholds based on absolute risk of cardiovascular disease to target drug treatment to lower blood pressure in the community.DesignModelling of three thresholds of treatment for hypertension based on the absolute risk of cardiovascular disease. 5 year risk of disease was estimated for each participant using an equation to predict risk. Net predicted impact of the thresholds on the number of people treated and the number of disease events averted over 5 years was calculated assuming a relative treatment benefit of one quarter.SettingAuckland, New Zealand.Participants2158 men and women aged 35-79 years randomly sampled from the general electoral rolls.Results46 374 (12%) Auckland residents aged 35-79 receive drug treatment to lower their blood pressure, averting an estimated 1689 disease events over 5 years. Restricting treatment to individuals with blood pressure ⩾170/100 mm Hg and those with blood pressure between 150/90-169/99 mm Hg who have a predicted 5 year risk of disease ⩾10% would increase the net number for whom treatment would be recommended by 19 401. This 42% relative increase is predicted to avert 1139/1689 (68%) additional disease events overall over 5 years compared with current treatment. If the threshold for 5 year risk of disease is set at 15% the number recommended for treatment increases by <10% but about 620/1689 (37%) additional events can be averted. A 20% threshold decreases the net number of patients recommended for treatment by about 10% but averts 204/1689 (12%) more disease events than current treatment.ConclusionsImplementing treatment guidelines that use treatment thresholds based on absolute risk could significantly improve the efficiency of drug treatment to lower blood pressure in primary care.     

Evaluation of computer based clinical decision support system and risk chart for management of hypertension in primary care: randomised controlled trial

ObjectivesTo investigate the effect of a computer based clinical decision support system and a risk chart on absolute cardiovascular risk, blood pressure, and prescribing of cardiovascular drugs in hypertensive patients.DesignCluster randomised controlled trial.Setting27 general practices in Avon.Participants614 patients aged between 60 and 79 years with high blood pressure.InterventionsPatients were randomised to computer based clinical decision support system plus cardiovascular risk chart; cardiovascular risk chart alone; or usual care.ResultsPatients in the computer based clinical decision support system and chart only groups were no more likely to have cardiovascular risk reduced to below 10% than patients receiving usual care. Patients in the computer based clinical decision support group were more likely to have a cardiovascular risk ⩾10% than chart only patients, odds ratio 2.3 (95% confidence interval 1.1 to 4.8). The chart only group had significantly lower systolic blood pressure compared with the usual care group (difference in means −4.6 mm Hg (95% confidence interval −8.4 to −0.8)). Reduction of diastolic blood pressure did not differ between the three groups. The chart only group were twice as likely to be prescribed two classes of cardiovascular drugs and over three times as likely to be prescribed three or more classes of drugs compared with the other groups.ConclusionsThe computer based clinical decision support system did not confer any benefit in absolute risk reduction or blood pressure control and requires further development and evaluation before use in clinical care can be recommended. Use of chart guidelines are associated with a potentially important reduction in systolic blood pressure.     

Is it possible to exclude a diagnosis of myocardial damage within six hours of admission to an emergency department? Diagnostic cohort study

ObjectiveTo assess the clinical efficacy and accuracy of an emergency department based six hour rule-out protocol for myocardial damage.DesignDiagnostic cohort study.SettingEmergency department of an inner city university hospital.Participants383 consecutive patients aged over 25 years with chest pain of less than 12 hours'' duration who were at low to moderate risk of acute myocardial infarction.InterventionSerial measurements of creatine kinase MB mass and continuous ST segment monitoring for six hours with 12 leads.ResultsOutcome of the gold standard test was available for 292 patients. On the diagnostic test for the protocol, 53 patients had positive results and 239 patients had negative results. There were 18 false positive results and one false negative result. Sensitivity was 97.2% (95% confidence interval 95.0% to 99.0%), specificity 93.0% (90.0% to 96.0%), the negative predictive value 99.6%, and the positive predictive value 66.0%. The positive likelihood ratio was 13.9 and the negative likelihood ratio 0.03.ConclusionsThe six hour rule-out protocol for myocardial infarction is accurate and efficacious. It can be used in patients presenting to emergency departments with chest pain indicating a low to moderate risk of myocardial infarction.

What is already known on this topic

Many patients with chest pain in emergency departments indicating a low to moderate risk of myocardial infarction are admitted to rule out myocardial damageSome 6% of those discharged have undiagnosed myocardial damage

What this study adds

An emergency department based chest pain assessment unit protocol to rule out myocardial damage is sensitive enough to allow safe discharge of patients at low to moderate risk of myocardial infarction within six hoursSuch units can also reduce the number of patients admitted unnecessarily     

Lipid concentrations and the use of lipid lowering drugs: evidence from a national cross sectional survey

ObjectiveTo evaluate the prevalence of the use of lipid lowering agents and its relation to blood lipid concentrations in English adults.DesignCross sectional survey.SettingEngland, 1998.ParticipantsNationally representative sample of 13 586 adults (aged ⩾16 years) living in non-institutional households.Results Mean total cholesterol concentrations were 5.47 (SE 0.02) mmol/l in men and 5.59 (0.02) mmol/l in women. Mean HDL cholesterol concentrations were 1.28 (0.01) mmol/l in men and 1.55 (0.01) mmol/l in women. Overall, of 10 569 adults who had a valid cholesterol measurement taken 7133 (67.5%; 95% confidence interval 66.5% to 68.4%) had a total cholesterol concentration ⩾5 mmol/l, 2804 (26.5%; 25.7% to 27.4%) had a ratio of total cholesterol to HDL cholesterol ⩾5 mmol/l, and 237 (2.2%; 1.9% to 2.5%) reported taking lipid lowering drugs. Of 117 participants with no history of cardiovascular disease but whose estimated 10 year risk of coronary heart disease was ⩾30% and whose total cholesterol concentration was ⩾5 mmol/l, four (3%) were taking lipid lowering drugs. Of 385 adults aged 16-75 with a history of coronary heart disease and eligible for lipid lowering treatment, 114 (30%; 25% to 34%) were taking lipid lowering drugs, of whom only 50 (44%; 35% to 53%) had a total cholesterol concentration <5 mmol/l.ConclusionsDespite the high prevalence of dyslipidaemia in English adults, the proportion of adults taking lipid lowering drugs in 1998 was only 2.2%. Rates of treatment were low among high risk patients eligible for primary prevention with lipid lowering drugs, and less than one third of patients with established cardiovascular disease received such treatment.