英国初级卫生保健质量与结果框架解析

目的 了解英国初级卫生保健质量与结果框架,为改善我国全科服务质量提供经验借鉴。 方法 文献综述与定性访谈。 结果 质量与结果框架作为全科服务合同的一部分,目的是通过引进激励机制改进服务质量,制定一套反映全科医疗服务质量的指标和评分体系,通过综合打分对全科医生的服务进行衡量。结论 在完善的组织管理、疾病登记体系和信息系统的支撑下,质量与结果框架有利于对全科服务进行标准化,统一的定价和支付体系有利于降低不同地区初级卫生保健的服务差异,激励了全科诊所服务的积极性。但也有专家学者指出了其中的一些弊端,有待进一步修正和完善。     

Early Child-Care Experiences and Children's Social Competence Between 11/2 and 15 Years of Age

The primary purpose of this longitudinal study was to examine the effects of early child-care experiences on children's social development between 11/2 and 15 years of age. A subsample of 52 children was selected from the Goteborg Child Care study. These children were selected because they were continuously enrolled in out-of-home care from 11/2 to 31/2 years of age. The first assessment was conducted prior to children's enrollment in out-of-home care and these children were followed over a 14-year period. Prior to 31/2 years of age, the amount of time spent in care and the quality of home and out-of-home care shaped the children's social skills. Individual differences in social competence with peers, as observed in out-of-home care settings, then began to stabilize. Thus, early child-care experiences appeared to influence social competence by fostering individual differences that remained stable through childhood and early adolescence.     

Bayesian profiling for cost with zeros to decompose total cost into probability of cost and mean nonzero cost

Cost of health care can vary substantially across hospitals, centers, or providers. Data from electronic health records provide information for studying patterns of cost variation and identifying high or low cost centers. Cost data often include zero values when patients receive no care, and joint two-part models have been developed for clustered cost data with zeros. Standard methods for center comparisons, sometimes called profiling, can use these methods to incorporate zero values into total cost. However, zero costs also provide opportunities to further examine sources of cost variation and outliers. For example, a hospital may have high (or low) cost due to frequency of nonzero cost, amount of nonzero cost, or a combination of those. We give methods for decomposing hospital differences in total cost with zeros into components for probability of use (i.e., of nonzero cost) and for cost of use (mean of nonzero cost). The components multiply to total cost and quantify components on the same easily interpreted multiplicative scales. The methods are based on Bayesian hierarchical models and counterfactual arguments, with Markov chain Monte Carlo estimation. We used simulated data to illustrate use, interpretation, and visualization of the methods in diverse situations, and applied the methods to 30,024 patients at 57 US Veterans Administration hospitals to characterize outlier hospitals in one year cost of inpatient care following a cardiac procedure. Twenty eight percent of patients had zero cost. These methods are useful in providing insight into cost variation and outliers for planning future studies or interventions.     

Quality of cardiovascular drugs prescribing in Croatia 2003-2008

The aim of the study was to determine cardiovascular drugs utilization and quality of prescribing in Croatia from 2003 to 2008. Data on the outpatient utilization of cardiovascular drugs in Croatia were collected during 2003-2008. Data on the size and number of packages, were obtained from Croatian institute for Health Insurance (CIHI). Based on the data obtained, the numbers of DDD and DDD per 1000 inhabitants per day (DDD/1000/day) were calculated for all cardiovascular drugs. Quality of drugs prescribing was assessing using Drug Utilization 90% (DU90%) method. Renin-angiotensin system agents showed highest share in the utilization of group C drugs, followed by calcium channel blockers. These two groups of drugs accounted for half of the overall cardiovascular drug utilization. Greatest changes were observed in the groups of renin-angiotensin system agents and hypolipemics. The number of drugs within DU90% segment increased between 2003 and 2008. In the same period Cost/DDD decreased.     

A cluster randomised controlled trial of an occupational therapy intervention for residents with stroke living in UK care homes (OTCH): study protocol

ABSTRACT: BACKGROUND: The occupational therapy (OT) in care homes study (OTCH) aims to investigate the effect of a targeted course of individual OT (with task training, provision of adaptive equipment, minor environmental adaptations and staff education) for stroke survivors living in care homes, compared to usual care. METHODS/DESIGN: A cluster randomised controlled trial of United Kingdom (UK) care homes (n?=?90) with residents (n?=?900) who have suffered a stroke or transient ischaemic attack (TIA), and who are not receiving end-of-life care. Homes will be stratified by centre and by type of care provided and randomised (50:50) using computer generated blocked randomisation within strata to receive either the OT intervention (3 months intervention from an occupational therapist) or control (usual care). Staff training on facilitating independence and mobility and the use of adaptive equipment, will be delivered to every home, with control homes receiving this after the 12 month follow-up.Allocation will be concealed from the independent assessors, but the treating therapists, and residents will not be masked to the intervention. Measurements are taken at baseline prior to randomisation and at 3, 6 and 12 months post randomisation. The primary outcome measure is independence in self-care activities of daily living (Barthel Activities of Daily Living Index). Secondary outcome measures are mobility (Rivermead Mobility Index), mood (Geriatric Depression Scale), preference based quality of life measured from EQ-5D and costs associated with each intervention group. Quality adjusted life years (QALYs) will be derived based on the EQ-5D scores. Cost effectiveness analysis will be estimated and measured by incremental cost effectiveness ratio. Adverse events will be recorded. DISCUSSION: This study will be the largest cluster randomised controlled trial of OT in care homes to date and will clarify the currently inconclusive literature on the efficacy of OT for stroke and TIA survivors residing in care homes. TRIAL REGISTRATION: ISRCTN00757750.     

Looking for a needle in a haystack: inference about individual fitness components in a heterogeneous population

Studies of wild vertebrates have provided evidence of substantial differences in lifetime reproduction among individuals and the sequences of life history ‘states’ during life (breeding, nonbreeding, etc.). Such differences may reflect ‘fixed’ differences in fitness components among individuals determined before, or at the onset of reproductive life. Many retrospective life history studies have translated this idea by assuming a ‘latent’ unobserved heterogeneity resulting in a fixed hierarchy among individuals in fitness components. Alternatively, fixed differences among individuals are not necessarily needed to account for observed levels of individual heterogeneity in life histories. Individuals with identical fitness traits may stochastically experience different outcomes for breeding and survival through life that lead to a diversity of ‘state’ sequences with some individuals living longer and being more productive than others, by chance alone. The question is whether individuals differ in their underlying fitness components in ways that cannot be explained by observable ‘states’ such as age, previous breeding success, etc. Here, we compare statistical models that represent these opposing hypotheses, and mixtures of them, using data from kittiwakes. We constructed models that accounted for observed covariates, individual random effects (unobserved heterogeneity), first‐order Markovian transitions between observed states, or combinations of these features. We show that individual sequences of states are better accounted for by models incorporating unobserved heterogeneity than by models including first‐order Markov processes alone, or a combination of both. If we had not considered individual heterogeneity, models including Markovian transitions would have been the best performing ones. We also show that inference about age‐related changes in fitness components is sensitive to incorporation of underlying individual heterogeneity in models. Our approach provides insight into the sources of individual heterogeneity in life histories, and can be applied to other data sets to examine the ubiquity of our results across the tree of life.     

The effects of time of day-specific resistance training on adaptations in skeletal muscle hypertrophy and muscle strength: A systematic review and meta-analysis

The present paper endeavored to elucidate the topic on the effects of morning versus evening resistance training on muscle strength and hypertrophy by conducting a systematic review and a meta-analysis of studies that examined time of day-specific resistance training. This systematic review was performed in accordance with the Preferred Reporting Items for Systematic Reviews and Meta-Analyses guidelines with searches conducted through PubMed/MEDLINE, Scopus, and SPORTDiscus databases. The Downs and Black checklist was used for the assessment of the methodological quality of the included studies. Studies that examined the effects of time of day-specific resistance training (while equating all other training variables, such as training frequency and volume, between the groups) on muscle strength and/or muscle size were included in the present review. The random effects model was used for the meta-analysis. Meta-analyses explored (1) the differences in strength expression between morning and evening hours at baseline; (2) the differences in strength within the groups training in the morning and evening by using their post-intervention strength data from the morning and evening strength assessments; (3) the overall differences between the effects of morning and evening resistance training (with subgroup analyses conducted for studies that assessed strength in the morning hours and for the studies that assessed strength in the evening hours). Finally, a meta-analysis was also conducted for studies that assessed muscle hypertrophy. Eleven studies of moderate and good methodological quality were included in the present review. The primary findings of the review are as follows: (1) at baseline, a significant difference in strength between morning and evening is evident, with greater strength observed in the evening hours; (2) resistance training in the morning hours may increase strength assessed in the morning to similar levels as strength assessed in the evening; (3) training in the evening hours, however, maintains the general difference in strength across the day, with greater strength observed in the evening hours; (4) when comparing the effects between the groups training in the morning versus in the evening hours, increases in strength are similar in both groups, regardless of the time of day at which strength assessment is conducted; and (5) increases in muscle size are similar irrespective of the time of day at which the training is performed.     

Early Childhood Music Education in Australia: A Snapshot

Policy for early childhood music education (birth to eight years of age) in Australia covers a complex and diverse range of curriculum guidelines and legislation relating to the contexts of day care, preschool, and the early years of school. Australian models and policies vary from state to state and according to setting. Furthermore, early childhood education is constantly changing and evolving, responding to new practices, altered government priorities and funding, and community needs. In this article, the author aims to provide a snapshot of the situation by reviewing and analyzing educational policies, teacher training, and providers of early childhood music programs as well as suggesting some future directions.     

Characteristics and Quality of Child Care for Toddlers and Preschoolers

In this article, we use data from the National Institute of Child Health and Human Development (NICHD) Study of Early Child Care (NICHD Early Child Care Research Network, 1996, 1997, 1998, 1999) to answer 3 questions. The first question is: What structural features and caregiver characteristics predict more positive caregiver behavior in child care for 1- to 3-year-old children? Positive caregiving was assessed in 5 types of care (centers, child-care homes, and care provided by in-home sitters, grandparents, and fathers) when children in the NICHD study were 15, 24, and 36 months of age (Ns = 612, 630, and 674). Across ages and types of care, positive caregiving was more likely when child-adult ratios and group sizes were smaller, caregivers were more educated, held more child-centered beliefs about childrearing, and had more experience in child care, and environments were safer and more stimulating. The second question is: What differences in caregiving are associated with the type of child care and the child's age? The highest level of positive caregiving was provided by in-home caregivers, including fathers and grandparents, caring for only 1 child, closely followed by home-based arrangements with relatively few children per adult. The least positive caregiving was found in center-based care with higher ratios of children to adults. By 36 months of age, the significance of child-adult ratio decreased, and in-home arrangements became less positive. The third question is: What is the overall quality of child care for 1- to 3-year-olds in the United States? Observed positive caregiving was determined to be "very uncharacteristic" for 6% of the children in the NICHD sample, "somewhat uncharacteristic" for 51%, "somewhat characteristic" for 32%, and "highly characteristic" for 12%. An extrapolation to the quality of care in the United States was derived by applying NICHD observational parameters, stratified by maternal education, child age, and care type, to the distribution of American families documented in the National Household Education Survey (Hofferth, Shauman, Henke, & West, 1998). Positive caregiving was extrapolated to be "very uncharacteristic" for 8% of children in the United States ages 1 to 3 years, "somewhat uncharacteristic" for 53%, "somewhat characteristic" for 30%, and "highly characteristic" for 9%.     

A quality improvement program for adolescents with cystic fibrosis: focus on psychosocial skills

Background

The two pediatric cystic fibrosis centers (CFCs) in Paris (Robert Debré) and Nantes, France, have been developing therapeutic patient education (TPE) programs since 2006 and have been engaged in the pilot phase of the quality improvement program (QIP) named the Hospital Program to Improve Outcomes and Expertise in Cystic Fibrosis (PHARE-M) since 2011. The objective was to improve the FEV1 of the cohort of adolescents to prepare them for their optimal transition to an adult CFC.

Methods

The two CFCs formed a multidisciplinary quality team and used the analysis of causes of insufficient respiratory function taking into account the adolescents’ psychosocial factors. At the Nantes CFC, the approach was centered on adolescents’ body image and their motivation to take care of themselves by assigning specific aspects of patient follow-up to each professional in the team. At R. Debré, an individual cause-and-effect diagram identified for each patient the medical and psychosocial factors that could account for insufficient respiratory function. Personalized actions were offered to each patient.

Results

In 2014, the median FEV1 (Forced Expiratory Volume in 1 Second) of the adolescent cohort exceeds 90% at the 2 CFCs (Nantes and R. Debré). Between 2011 and 2014 both centers improved their ranking for FEV1% in adolescents in the Registry histograms. At R. Debré, the personalized process allowed to reinforce equality of care, offering to all the opportunity to benefit from TPE sessions and coaching with an adapted physical activity teacher. The psychologist developed a specific tool to support the patient-centered process.

Conclusion

The link between TPE and QIP was strong at our two centers enhancing patient centered care and targeting an optimal transition to an adult program.

     

Is WIC effective in improving pregnancy-related outcomes? An empirical reassessment

This study provides new evidence on how prenatal WIC participation influences pregnancy-related outcomes, using a large dataset of Medicaid mothers with two or more singleton births. Our analysis suggests there is negative selection by maternal unobserved factors even with a relatively homogenous sample and a rich set of observed characteristics. The conservative estimates from multiple regression which doesn’t address maternal unobserved heterogeneity already demonstrate beneficial effects on a range of outcomes. The concern of mis-specification or extrapolation in the linear model is also ruled out. Controlling for the mother fixed effects, we find more statistically significant estimates which are usually larger in size. The within-mother estimates are robust in a series of sensitivity checks especially multiple inference adjustments. Overall, we find WIC does work to improve infant health and maternal health behaviors as well as reduce usage of costly maternity care.     

A model with space-varying regression coefficients for clustering multivariate spatial count data

Multivariate spatial count data are often segmented by unobserved space-varying factors that vary across space. In this setting, regression models that assume space-constant covariate effects could be too restrictive. Motivated by the analysis of cause-specific mortality data, we propose to estimate space-varying effects by exploiting a multivariate hidden Markov field. It models the data by a battery of Poisson regressions with spatially correlated regression coefficients, which are driven by an unobserved spatial multinomial process. It parsimoniously describes multivariate count data by means of a finite number of latent classes. Parameter estimation is carried out by composite likelihood methods, that we specifically develop for the proposed model. In a case study of cause-specific mortality data in Italy, the model was capable to capture the spatial variation of gender differences and age effects.     

Evaluating the role of income,state dependence and individual specific heterogeneity in the determination of subjective health assessments

This paper investigates the role of various determinants of an individual's subjective self-assessment of own health. While the economics literature has focused primarily on the role of income on these assessments, we include an examination of the role of state dependence and unobserved individual specific time invariant heterogeneity. We employ a dynamic fixed effects ordered choice model to examine the responses of Australian residents. We find no statistically significant relationship between transitory income and health responses. We also find that while there is evidence of state dependence, this does not appear to be responsible for the distribution of responses. Our results suggest that the variation in the individual specific effects, comprising both observed and unobserved time invariant factors, is primarily responsible for the variation across individuals’ responses.     

Cost effectiveness of self monitoring of blood glucose in patients with non-insulin treated type 2 diabetes: economic evaluation of data from the DiGEM trial

Objective To assess the cost effectiveness of self monitoring of blood glucose alone or with additional training in incorporating the results into self care, in addition to standardised usual care for patients with non-insulin treated type 2 diabetes.Design Incremental cost utility analysis from a healthcare perspective. Data on resource use from the randomised controlled diabetes glycaemic education and monitoring (DiGEM) trial covered 12 months before baseline and 12 months of trial follow-up. Quality of life was measured at baseline and 12 months using the EuroQol EQ-5D questionnaire.Setting Primary care in the United Kingdom.Participants 453 patients with non-insulin treated type 2 diabetes.Interventions Standardised usual care (control) compared with additional self monitoring of blood glucose alone (less intensive self monitoring) or with training in self interpretation of the results (more intensive self monitoring).Main outcome measures Quality adjusted life years and healthcare costs (sterling in 2005-6 prices).Results The average costs of intervention were £89 (€113; $179) for standardised usual care, £181 for less intensive self monitoring, and £173 for more intensive self monitoring, showing an additional cost per patient of £92 (95% confidence interval £80 to £103) in the less intensive group and £84 (£73 to £96) in the more intensive group. No other significant cost difference was detected between the groups. An initial negative impact of self monitoring on quality of life occurred, averaging −0.027 (95% confidence interval−0.069 to 0.015) for the less intensive self monitoring group and −0.075 (−0.119 to −0.031) for the more intensive group.Conclusions Self monitoring of blood glucose with or without additional training in incorporating the results into self care was associated with higher costs and lower quality of life in patients with non-insulin treated type 2 diabetes. In light of this, and no clinically significant differences in other outcomes, self monitoring of blood glucose is unlikely to be cost effective in addition to standardised usual care.Trial registration Current Controlled Trials ISRCTN47464659.     

Variation in HIV care and treatment outcomes by facility in South Africa, 2011–2015: A cohort study

BackgroundDespite widespread availability of HIV treatment, patient outcomes differ across facilities. We propose and evaluate an approach to measure quality of HIV care at health facilities in South Africa’s national HIV program using routine laboratory data.Methods and findingsData were extracted from South Africa’s National Health Laboratory Service (NHLS) Corporate Data Warehouse. All CD4 counts, viral loads (VLs), and other laboratory tests used in HIV monitoring were linked, creating a validated patient identifier. We constructed longitudinal HIV care cascades for all patients in the national HIV program, excluding data from the Western Cape and very small facilities. We then estimated for each facility in each year (2011 to 2015) the following cascade measures identified a priori as reflecting quality of HIV care: median CD4 count among new patients; retention 12 months after presentation; 12-month retention among patients established in care; viral suppression; CD4 recovery; monitoring after an elevated VL. We used factor analysis to identify an underlying measure of quality of care, and we assessed the persistence of this quality measure over time. We then assessed spatiotemporal variation and facility and population predictors in a multivariable regression context.We analyzed data on 3,265 facilities with a median (IQR) annual size of 441 (189 to 988) lab-monitored HIV patients. Retention 12 months after presentation increased from 42% to 47% during the study period, and viral suppression increased from 66% to 79%, although there was substantial variability across facilities. We identified an underlying measure of quality of HIV care that correlated with all cascade measures except median CD4 count at presentation. Averaging across the 5 years of data, this quality score attained a reliability of 0.84. Quality was higher for clinics (versus hospitals), in rural (versus urban) areas, and for larger facilities. Quality was lower in high-poverty areas but was not independently associated with percent Black. Quality increased by 0.49 (95% CI 0.46 to 0.53) standard deviations from 2011 to 2015, and there was evidence of geospatial autocorrelation (p < 0.001). The study’s limitations include an inability to fully adjust for underlying patient risk, reliance on laboratory data which do not capture all relevant domains of quality, potential for errors in record linkage, and the omission of Western Cape.ConclusionsWe observed persistent differences in HIV care and treatment outcomes across South African facilities. Targeting low-performing facilities for additional support could reduce overall burden of disease.

Jacob Bor and co-workers use a new measure of care quality to report on facility-level variations in HIV care and outcomes in South Africa.     

Teacher–child interaction quality as a function of classroom age diversity and teachers’ beliefs and qualifications

Data from 332 teachers who participated in the National Center for Research on Early Childhood Education study were used to examine the implications of classroom age diversity in preschool programs for teacher interactions with students in areas of instructional and emotional support, and classroom organization. Teachers in early childhood classrooms with greater age diversity within a school year and who experienced an increase in age diversity across years exhibited less optimal teacher–child interactions. The negative effects of age diversity for teacher–child interactions were only noticeable among teachers with fewer years of education and experience, and among teachers whose views of children were less child-centered. When taken together, results indicate that closer attention should be paid to the consequences of classroom age diversity in preschool and that a multi-year perspective on teachers’ classroom experiences would allow for a more nuanced understanding of the quality of teacher–child interactions.     

Rural-to-Urban Migrants' Experiences with Primary Care under Different Types of Medical Institutions in Guangzhou,China

Objectives

China is facing the unprecedented challenge of rapidly increasing rural-to-urban migration. Migrants are in a vulnerable state when they attempt to access to primary care services. This study was designed to explore rural-to-urban migrants’ experiences in primary care, comparing their quality of primary care experiences under different types of medical institutions in Guangzhou, China.

Methods

The study employed a cross-sectional survey of 736 rural-to-urban migrants in Guangzhou, China in 2014. A validated Chinese version of Primary Care Assessment Tool—Adult Short Version (PCAT-AS), representing 10 primary care domains was used to collect information on migrants’ quality of primary care experiences. These domains include first contact (utilization), first contact (accessibility), ongoing care, coordination (referrals), coordination (information systems), comprehensiveness (services available), comprehensiveness (services provided), family-centeredness, community orientation and culturally competent. These measures were used to assess the quality of primary care performance as reported from patients’ perspective. Analysis of covariance was conducted for comparison on PCAT scores among migrants accessing primary care in tertiary hospitals, municipal hospitals, community health centers/community health stations, and township health centers/rural health stations. Multiple linear regression models were used to explore factors associated with PCAT total scores.

Results

After adjustments were made, migrants accessing primary care in tertiary hospitals (25.49) reported the highest PCAT total scores, followed by municipal hospitals (25.02), community health centers/community health stations (24.24), and township health centers/rural health stations (24.18). Tertiary hospital users reported significantly better performance in first contact (utilization), first contact (accessibility), coordination (information system), comprehensiveness (service available), and cultural competence. Community health center/community health station users reported significantly better experience in the community orientation domain. Township health center/rural health station users expressed significantly better experience in the ongoing care domain. There were no statistically significant differences across settings in the ongoing care, comprehensiveness (services provided), and family-centeredness domains. Multiple linear regression models showed that factors positively associated with higher PCAT total scores also included insurance covering parts of healthcare payment (P<0.001).

Conclusions

This study highlights the need for improvement in primary care provided by primary care institutions for rural-to-urban migrants. Relevant policies related to medical insurance should be implemented for providing affordable healthcare services for migrants accessing primary care.     

Early programmes of high and low intensity exercise and quality of life after acute myocardial infarction.

OBJECTIVE--To determine whether a group programme of light exercise could improve quality of life in patients after acute myocardial infarction to the same extent as a high intensity exercise training programme. SETTING--Australian teaching hospital. PATIENTS--224 men from a consecutive series of 339 men under 70 admitted to a coronary care unit with transmural acute myocardial infarction. INTERVENTION--Patients were randomly allocated in hospital to a group programme lasting eight weeks of either high intensity exercise training or light exercise. MAIN OUTCOME MEASURES--Physical working capacity based on metabolic equivalents achieved from treadmill exercise tests at entry, after 11 weeks, and after one year. Quality of life based on self report scores of anxiety, depression, denial, and wellbeing and interview assessments of activities and psychosocial adjustment at entry, after four months, and after one year. RESULTS--The two groups were well matched at entry. At 11 weeks the mean results of treadmill testing were 10.7 (95% confidence interval 10.20 to 11.20) metabolic equivalents for exercise training and 9.7 (9.26 to 10.14) for light exercise (t = 2.85, df = 181, p = 0.005). Apart from this small temporary benefit in mean physical working capacity, there were no significant differences between groups. Improvement in occupational adjustment score from baseline to four months was greater after exercise training than after light exercise, but at one year repeated measures analysis of variance showed no significant effects of treatment or interaction between treatment and time point. CONCLUSION--The effects on quality of life of a low cost programme of light exercise are similar to those obtained from a high intensity exercise training programme.     

Women in medicine: practice patterns and attitudes.

Increasing numbers of women are entering medicine in Canada. In 1959 women accounted for 6% of the medical school graduates, but by 1989 they accounted for 44%. Although there has been little systematic investigation of the impact of this increase on Canada''s health care system, there are grounds for believing that female physicians bring with them distinctive values and interests, which may be reflected in the way they conduct their professional practices. We used data from a recent national survey of 2398 Canadian physicians to examine differences between women and men in their practices and their attitudes toward health care issues. Significant differences were found in the organization and management of the practices. Women preferred group over solo practice and were overrepresented in community health centres, health service organizations and centres locaux de services communautaires in Quebec. One-third of the women, as compared with half of the men, were in specialties. Even after adjusting for differences in workloads the incomes of the women were significantly lower than those of the men. Only minor differences were observed in the assessment of the health care system and alternative modes of organizing health care services. We believe that the differences were due to the double workload of women as professionals and family caregivers and the powerful socialization effects of medical education. As women overcome their minority status in the medical profession, differences between the sexes may become more apparent. Thus, the extent and effects of the progressive increase in the number of women in Canadian medicine should be assessed on an ongoing basis.     

Cost effectiveness analysis of early zidovudine treatment of HIV infected patients.

OBJECTIVE--To compare cost effectiveness of early and later treatment with zidovudine for patients infected with HIV. DESIGN--Markov chain analysis of cost effectiveness based on results of use of health care and efficacy from a trial of zidovudine treatment. SETTING--Seven Veterans Affairs medical centres in the United States. SUBJECTS--338 patients with symptomatic HIV infection and a lymphocyte count of 200 x 10(6) to 500 x 10(6) CD4 cells/l. INTERVENTIONS--Zidovudine 1500 mg/day started either at recruitment to the trial or when CD4 cell count fell below 200 x 10(6)/l. MAIN OUTCOME MEASURES--Health care costs and rates of disease progression between six clinical states of HIV infection. RESULTS--Patients given early treatment with zidovudine remained without AIDS for an extra two months at a cost of $10,750 for each extra month without AIDS (at 1991 costs). Cost effectiveness ratio was most sensitive to the cost of zidovudine and to the quality of life of patients receiving early treatment. At treatment of 500 mg/day the cost effectiveness ratio for early treatment was $5432 for each extra month without AIDS. Patients given early treatment experienced more side effects, and if their quality of life was devalued by 8% compared with patients treated later the two treatments were equivalent in terms of quality adjusted months of life without AIDS. CONCLUSIONS--Early treatment with zidovudine is expensive and is very sensitive to the cost of zidovudine and to potential reductions in quality of life of patients who experience side effects. Doctors should reconsider early treatment with zidovudine for patients who experience side effects that substantially compromise their quality of life.