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M Zwarenstein

Publications and source records attributed to M Zwarenstein.

At least 37 records · Page 2Linked to original sources
PubMed2000

An effectiveness trial of a diagnostic test in a busy outpatients department in a developing country: issues around allocation concealment and envelope randomization.

Methods to ensure allocation concealment in a randomized controlled trial in a busy outpatients department may disrupt usual clinical behavior, and thereby modify the effect of a diagnostic test. In a clinical trial of chest radiography in ambulatory children, concealment was maintained by means of sealed sequentially numbered manila envelopes. Baseline information was collected on all potential participants before they were presented to a clinician for a decision on inclusion in the trial. Excluded patients were followed up. Of 59 excluded patients, only 16 allocation envelopes had been opened or were not accounted for, although 12 of these had non-radiograph allocations (P = 0.05). There was no difference between patients excluded from radiograph and non-radiograph groups in baseline characteristics or primary outcome measure. Most of the improper exclusions occurred early in the study; improved monitoring and feedback reduced the problem. Sealed opaque sequentially numbered envelopes may be appropriate for trials of diagnostic tests in settings where centralized randomization is not feasible, and given careful monitoring of the enrollment process.

Child↗
PubMed2000

A randomised controlled trial of lay health workers as direct observers for treatment of tuberculosis.

SETTING: Study conducted in a suburb of Cape Town, South Africa. OBJECTIVE: Comparison of successful tuberculosis treatment outcome rates between self supervision, supervision by lay health worker (LHW), and supervision by clinic nurse. METHODS: Open, randomised, controlled trial with intention-to-treat analysis. RESULTS: All groups (n = 156) achieved similar outcomes (LHW vs. clinic nurse: risk difference 17.2%, 95% confidence interval [CI] -0.1-34.5; LHW vs. self supervision 15%, 95%CI -3.7-33.6). New patients benefit from LHW supervision (LHW vs clinic nurse: risk difference 24.2%, 95%CI 6-42.5, LHW vs. self supervision 39.1%, 95%CI 17.8-60.3) as do female patients (LHW vs. clinic nurse 48.3%, 95%CI 22.8-73.8, LHW vs. self supervision 32.6%, 95%CI 6.4-58.7). CONCLUSIONS: LHW supervision approaches statistically significant superiority, but fails to reach it most likely due to the study's limitation, the small sample size. It is possible that subgroups (new and female patients) do well under LHW supervision. LHW supervision could be offered as one of several supervision options within TB control programmes.

Adult↗
PubMed1998

Randomised controlled trial of self-supervised and directly observed treatment of tuberculosis.

BACKGROUND: Tuberculosis is a major public-health problem in South Africa, made worse by poor adherence to and frequent interruption of treatment. Direct observation (DO) of tuberculosis patients taking their drugs is supposed to improve treatment completion and outcome. We compared DO with self-supervision, in which patients on the same drug regimen are not observed taking their pills, to assess the effect of each on the success of tuberculosis treatment. METHODS: We undertook an unblinded randomised controlled trial in two communities with large tuberculosis caseloads. The trial included 216 adults who started pulmonary tuberculosis treatment for the first time, or who had a second course of treatment (retreatment patients). No changes to existing treatment delivery were made other than randomisation. Analysis was by intention to treat. Individual patient data from the two communities were combined. FINDINGS: Treatment for tuberculosis was more successful among self-supervised patients (60% of patients) than among those on DO (54% of patients, difference between groups 6% [90% CI -5.1 to 17.0]). Retreatment patients had significantly more successful treatment outcomes if self-supervised (74% of patients) than on DO (42% of patients, difference between groups 32% [11%-52%]). INTERPRETATION: At high rates of treatment interruption, self-supervision achieved equivalent outcomes to clinic DO at lower cost. Self-supervision achieved better outcomes for retreatment patients. Supportive patient-carer relations, rather than the authoritarian surveillance implicit in DO, may improve treatment outcomes and help to control tuberculosis.

Adult↗
PubMed1998

Randomised controlled trial of clinical outcome after chest radiograph in ambulatory acute lower-respiratory infection in children.

BACKGROUND: When available, chest radiographs are used widely in acute lower-respiratory-tract infections in children. Their impact on clinical outcome is unknown. METHODS: 522 children aged 2 to 59 months who met the WHO case definition for pneumonia were randomly allocated to have a chest radiograph or not. The main outcome was time to recovery, measured in a subset of 295 patients contactable by telephone. Subsidiary outcomes included diagnosis, management, and subsequent use of health facilities. FINDINGS: There was a marginal improvement in time to recovery which was not clinically significant. The median time to recovery was 7 days in both groups (95% CI 6-8 days and 6-9 days in the radiograph and control groups respectively, p=0.50, log-rank test) and the hazard ratio for recovery was 1.08 (95% CI 0.85-1.34). This lack of effect was not modified by clinicians' experience and no subgroups were identified in which the chest radiograph had an effect. Pneumonia and upper-respiratory infections were diagnosed more often and bronchiolitis less often in the radiograph group. Antibiotic use was higher in the radiograph group (60.8% vs 52.2%, p=0.05). There was no difference in subsequent use of health facilities. INTERPRETATION: Chest radiograph did not affect clinical outcome in outpatient children with acute lower-respiratory infection. This lack of effect is independent of clinicians' experience. There are no clinically identifiable subgroups of children within the WHO case definition of pneumonia who are likely to benefit from a chest radiograph. We conclude that routine use of chest radiography is not beneficial in ambulatory children aged over 2 months with acute lower-respiratory-tract infection.

Acute Disease↗
PubMed1998

A flow diagram to facilitate selection of interventions and research for health care.

Decisions about health care should be informed by systematic review of valid research evidence on the effects of interventions on health outcomes that matter. If systematic review suggests it is likely that a health care intervention does more good than harm in some settings, questions must be addressed about the local applicability of the intervention, its cost-effectiveness, and feasibility of implementation. If systematic review suggests that it is unlikely that an intervention does more good than harm in any setting, its use should be discouraged, while existing interventions are improved or alternative interventions developed. If it is uncertain whether an intervention does more good than harm, further analysis of existing data or new controlled trials are required. The article contains a flow diagram, which provides a structure for making such decisions.

Cost-Benefit Analysis↗
PubMed1998

Underrecognition and undertreatment of asthma in Cape Town primary school children.

BACKGROUND: In view of the high local prevalence of asthma, the extent of recognition and appropriate management of childhood asthma was studied in a large suburban area of Cape Town. DESIGN: Cross-sectional study based on random community sample of schools. METHOD: 1,955 parents of sub B pupils from 16 schools completed a questionnaire, followed by: (i) an interview of the parents of 348 symptomatic children; and (ii) bronchial responsiveness testing on 254 children. The final case group consisted of 242 children with reported asthma or multiple asthma symptoms on both questionnaires. Children in whom asthma was acknowledged were compared with those in whom it was not. RESULTS: Overall, any past or current ('ever') asthma was acknowledged by respondents in only 53% of the children, and current asthma in only 37.1%. While most children had received treatment in the previous 12 months, 66.1% of the recognised group were on current treatment (23.2% on daily treatment), compared with 37% of the unrecognised group (3% daily). Salbutamol and theophylline syrups were the most common types of medication, while inhalers and anti-inflammatory medications were underused. Only a minority of parents reported the child ever having used a peak flow meter, or volunteered knowledge of preventive measures. Current treatment, and to a lesser degree recognition of asthma by parents, were more common among children on medical aid and of higher socio-economic status. CONCLUSIONS: These findings suggest that ways need to be found: (i) to increase the use of current asthma treatment guidelines by practitioners; (ii) to provide access to comprehensive care by children not on medical aid; and (iii) to improve education of parents in home management measures such as severity assessment and avoidance of smoking, allergen and dietary triggers.

Asthma↗
PubMed1997

Most patients attending a 'walk-in' clinic at Red Cross War Memorial Children's Hospital could safely be managed at primary care level.

OBJECTIVES: (i) To ascertain what proportion of patients attending the general medical outpatient service at Red Cross War Memorial Children's Hospital (RXH) could safely be managed at peripheral primary care facilities; and (ii) to measure the effect of the introduction of free health care for children under 6 years of age on requirements for levels of care ranging from home to super-specialist referral centres. DESIGN: Prospective survey of patients attending on a stratified, randomised sample of 7 days in March 1994 (N = 1 962) and again in November 1994 (N = 1 404)-before and after the introduction on 6 June 1994 of free care for children under 6 years of age. SETTING: The general outpatient department of an academic/referral children's hospital. PATIENT SELECTION: All patients attending the outpatient department on the study days (7h00 to 6h59 the following day), excluding those who were referred, returning for follow-up, attending a specialist clinic or attending the surgical outpatient department. QUESTIONNAIRE: The questionnaire completed by medical officers recorded the following: patient's name, folder number, date and time of arrival, whether referred, clinic, treating doctor, disposal, diagnoses, home suburb and the level of care required: (i) home: (ii) clinic without a doctor; (iii) clinic with a doctor; (iv) hospital with non-specialists; (v) hospital with general paediatricians; or (vi) super-specialist hospital. MAIN RESULTS: In March 1994 the percentages of unreferred patients requiring the 6 levels of care defined for the study were 0.3, 25, 62, 8, 3 and 1, respectively. In November 1994 the percentages were 4, 41, 43, 8, 4 and 1. The graph of the number of patients seen at the outpatient department each month shows a large month-to-month variation but the trend is clearly towards an increase. CONCLUSIONS: The general medical outpatient department at RXH provides care to a large number of children, 48% of whom are unreferred. Of the unreferred patients 95% could be treated (more appropriately for the health services and more conveniently for their families) at a local primary health care facility. The situation has been aggravated by the introduction of free care for children under 6 years of age, who constitute 83% of the unreferred workload.

Child Health Services↗
PubMed1996

Prevalence of psychiatric morbidity in the adult population of a rural South African village.

We report on the first South African two-stage community prevalence study of psychiatric morbidity, conducted in Mamre, a rural "coloured' village, 50 km from Cape Town. Randomly selected adults (N = 481) were assessed using the Self-Reporting Questionnaire (SRQ) as a first-stage screen and the Present State Examination (PSE-9) was administered to a proportion of the sample (N = 121) as the second-stage criterion. Demographic, health care utilization, and substance abuse data were also collected. Using the PSE-9 CATEGO Index of Definition of 5, the weighted prevalence of psychiatric morbidity was 27.1% (confidence interval of 19.5-34.7%), the majority of cases being given a tentative diagnosis of depressive or anxiety disorder. The CATEGO algorithm may not be fully appropriate in this cultural context as there was an apparent over-diagnosis of paranoid states. The SRQ's weighted sensitivity and specificity were 0.49 and 0.82 respectively. Overall, the SRQ correctly identified 67% of cases and non-cases. No demographic variables predicted psychiatric morbidity, but there was an indirect link between morbidity and primary care utilization. Further South African studies of the validity of both the SRQ and of criterion instruments are needed. These may contribute to knowledge regarding cultural factors affecting psychiatric diagnosis.

Adolescent↗
PubMed1996

Risk factors for childhood asthma and wheezing. Importance of maternal and household smoking.

To identify modifiable risk factors for wheezing illness in childhood, the associations between current asthma or wheezing and factors such as household smoking, damp and dietary salt preference were measured in a questionnaire-based prevalence study of schoolchildren 7 to 9 yr of age in Cape Town. In a random sample of 15 schools, questionnaires were completed by parents of 1,955 children, from which 368 cases and 294 controls were selected on the basis of reported asthma diagnosis or symptoms. Urinary cotinine concentrations were measured, and the parents were interviewed. An exposure-response relationship between the urinary cotinine creatinine ratio and asthma/wheeze was observed. In multivariate analysis, predictors of asthma/wheeze were hay fever (odds ratio [OR] - 5.30; 95% confidence interval [CI] = 3.16 to 8.89), eczema (OR = 2.19; 95% CI = 1.33-3.62), parental asthma (OR = 1.77; 95% CI = 1.11 to 2.84), absence of paternal contribution to income (OR = 1.72; 95% CI = 1.17 to 2.54), maternal smoking in pregnancy (OR = 1.87; 95% CI = 1.25 to 2.81), and each additional household smoker (OR = 1.15; 95% CI = 1.01 to 1.30). Findings were similar, with higher odds ratios for most variables, except number of household smokers, when the group was restricted to children with parent-reported asthma. The findings confirm that household smoking is an important modifiable risk factor in asthma/wheeze among young schoolchildren, and they suggest that maternal smoking in pregnancy and current household exposure are independent contributors to this effect.

Asthma↗
PubMed1995

Prevalence and reliability of asthma symptoms in primary school children in Cape Town.

BACKGROUND: Childhood asthma is believed to be a serious problem in Cape Town, South Africa. This study aimed to measure the prevalence and reliability of asthma symptoms and reported asthma in Cape Town schoolchildren aged mainly 7 and 8 years, and to assess underdiagnosis. METHOD: A questionnaire was completed by parents of 1955 children, followed by 620 personal interviews repeating the questions. RESULTS: The prevalence of recent wheeze (previous 12 months) (26.8%) was high by international comparison, but not that of reported asthma (10.8%). Among children with more than 12 recent attacks of wheeze, only 60% were reported as asthmatic and 55% as receiving regular treatment. Symptom prevalences varied with the respondent's familial relationship to the child. On some questions the interview produced higher wheeze prevalences than the self-administered questionnaire. Repeatability of questions varied: asthma over (kappa = 0.69), recent wheeze (kappa = 0.59), and recent sleep disturbance by wheeze (kappa = 0.56) were the most reliable. CONCLUSIONS: Prevalence based on symptom reports may vary with the respondent and between self- and interviewer-administered questionnaires. Also, certain questions currently proposed for childhood asthma questionnaires may be unreliable. Nevertheless, it can be concluded that the prevalence of wheeze is high in this population, and that underdiagnosis and undertreatment of asthma are a problem.

Asthma↗
PubMed1995

Is HIV/AIDS a primary-care disease? Appropriate levels of outpatient care for patients with HIV/AIDS.

OBJECTIVE: To estimate the proportion of outpatient visits that could be managed at a primary-care level, by World Health Organization (WHO) clinical staging. DESIGN: Prospective, descriptive study. Six medical doctors in a tertiary hospital HIV ambulatory clinic recorded clinical diagnoses, WHO clinical staging and their recommendation regarding the appropriate level of care for each outpatient seen. SETTING AND STUDY POPULATION: All HIV-infected patients attending a public-sector, urban, South African, referral and teaching hospital HIV outpatient clinic between September and November 1992. PARTICIPANTS: There were 238 visits by 148 patients during the study period. RESULTS: Of 238 visits, 165 (69.3%) were deemed suitable for treatment at the primary-care level. After allowing for contradictory responses, at least 141 visits (59.2%) could be appropriately treated at the primary-care level. Although all six doctors assessed more than half of their visits as suitable for primary care, there were significant differences among them. In total, 83 visits (34.8%) needed a medical specialist, and 45 (18.9%) required tertiary-care facilities. Of all the visits, 58 (24.9%), 51 (21.9%), 60 (25.8%) and 64 (27.4%) were classified as WHO stages 1, 2, 3 and 4, respectively. For these stages, 55 (94.8%), 38 (74.5%), 42 (70.0%) and 26 (40.5%) visits, respectively, were suitable for treatment at a primary-care facility. CONCLUSIONS: Many of the outpatient visits to this outpatient specialist clinic could have been safely cared for at a primary-care level. As the severity of the disease increases, there is a decrease in the proportion of patients that can be treated at a primary-care level.

Acquired Immunodeficiency Syndrome↗
PubMed1995

Tuberculosis drug resistance in the Western Cape.

OBJECTIVES: Drug resistance is a serious problem in the treatment of tuberculosis and a threat to successful tuberculosis control programmes. Local health workers have expressed concern that the increasing tuberculosis epidemic in the Western Cape is partly attributable to drug resistance. The aim of this study was to determine the prevalence of tuberculosis drug resistance (including multidrug resistance) and to investigate possible relationships between drug resistance and patient demographic characteristics. DESIGN, SETTING, SUBJECTS, OUTCOME MEASURES: During a defined period, all adult (> or = 15 years) patients with pulmonary tuberculosis (confirmed by culture) from all tuberculosis clinics in the Western Cape were included. Previous tuberculosis treatment history was obtained by interviews, utilising a standardised questionnaire. Acquired drug resistance was determined on cultures from patients with a prior history of tuberculosis treatment, while initial resistance was determined from tuberculosis cases with no history of previous treatment. RESULTS: Data from 7,266 patients were analysed. After adjusting for missing information by way of a random sample validation study, 32% of patients were found to have a history of previous treatment, 63% indicated no previous treatment, and in 5% the treatment history was unknown. Rates for initial resistance were found to be low at 3,9% for isoniazid, 1,1% for rifampicin and 0,2% for ethambutol. Combined resistance to isoniazid and rifampicin (multidrug resistance) was found to be 1,1% in patients not treated before. Acquired resistance rates were higher at 10,8% for isoniazid, 4,2% for rifampicin, 0,3% for ethambutol and 4,0% for multidrug resistance. Logistic regression analysis of the data indicated that drug resistance was not influenced by population group, gender or age. Patients with a history of tuberculosis treatment were found to be at an increased risk of developing drug resistance (relative risk 2,6). Some regions in the Western Cape had higher proportions of previously treated patients with consequent higher acquired resistance rates. CONCLUSIONS: Results from this study indicated that drug resistance is currently not a major problem in the Western Cape, rates comparing favourably with those reported from developed countries and being much lower than those for developing countries. Every effort should therefore be made to maintain the status quo and to prevent the emergence of further resistance. The priority for tuberculosis control in the Western Cape should remain to limit transmission of the disease by reducing the infectious pool through improved cure of (especially) smear-positive cases.

Adolescent↗
PubMed1994

The introverted medical school--time to rethink medical education.

Curricular reform in the education of medical students is highlighted within the context of changing patterns of provision of health care. A number of industrialised countries' medical schools have accepted that they have a 'social contract' to respond to the health needs of the populations they serve. Such a contract, and the commitment to populations which it would necessitate, is also relevant in the South African context.

Curriculum↗
PubMed1994

A national sentinel surveillance network for the measurement of ill-health in South Africa. A prerequisite for epidemiological research and health planning.

Data on births, on deaths by cause and on morbidity are essential in planning appropriate health interventions, but the scarcity of these data in South Africa is striking. Some of the limitations of national mortality and morbidity data collection systems are reviewed. In order to improve the usefulness of vital statistical information, it is proposed that active disease monitoring be introduced in a number of surveillance sites where the population has been properly enumerated. A network of these sites would routinely gather information on births and deaths by cause and on a list of conditions that are: (i) easy to identify clinically; (ii) would bring most people to the attention of health personnel; and (iii) would indicate failure of health service provision, environmental control or resource allocation. The measurement of the geographical variation of a number of conditions, coupled with geographical information on health care indicators and risk and health promotive factors in each site, would facilitate the planning of interventions in a rational manner.

Female↗