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Biomedical subjects

S Ebrahim

Publications and source records attributed to S Ebrahim.

At least 109 records · Page 6Linked to original sources
PubMed2001

The use of numbers needed to treat derived from systematic reviews and meta-analysis. Caveats and pitfalls.

Numbers needed to treat (NNTs) may be used to present the effects of treatment and are the reciprocal of the absolute difference between treatment and control groups in a randomized controlled trial. NNTs are sensitive to factors that change the baseline risk of trial participants: the outcome considered; characteristics of patients; secular trends in incidence and case-fatality; and clinical setting. NNTs derived from pooled absolute risk differences in meta-analyses are commonly presented and easily calculated by meta-analytic software but may be seriously misleading because of heterogeneity between trials included in meta-analyses. Meaningful NNTs are obtained by applying the pooled relative risk reductions calculated from meta-analyses or individual trials to the baseline risk relevant to specific patient groups. This process will give a range of NNTs depending on whether patients are at high, low, or intermediate levels of risk, rather than a potentially misleading single number.

Clinical Trials as Topic↗
PubMed2001

Cross-cultural validation of the London Handicap Scale in Hong Kong Chinese.

STUDY OBJECTIVE: To investigate the cross-cultural validity of London Handicap Scale in Hong Kong Chinese. DESIGN: Ratings of the utility of 10 hypothetical health scenarios were given by groups of HK Chinese subjects. Measured scores were compared with calculated scores from published scale weights of London Handicap Scale, which were based on utility ratings made by UK subjects. SETTING: A rehabilitation hospital in Hong Kong. SUBJECTS: A total of 164 HK Chinese, comprising doctors, medical students, nonmedical hospital staff, geriatric day hospital stroke and nonstroke patients, community day-care centre elderly, old age hostel elderly, young disabled inpatients and young community-dwelling disabled citizens. MAIN RESULTS: There was a close correlation between the mean scores of HK subjects and the calculated scores derived from the published UK scale weights, apart from one scenario (Pearson's correlation coefficient r = 0.87 p = 0.001). The correlations were high for all subgroups, between which there was good consensus. Measured utilities were significantly different between subgroups for only one scenario. For this scenario of moderate to severe handicap in mobility, physical dependence, occupation and social integration, but with excellent orientation and economic self sufficiency: (1) older age groups gave better scores than younger age groups (p < 0.0005); (2) subjects with poor subjective health status gave better scores than those with good subjective health status (p = 0.002); (3) subjects related to the medical or hospital field, i.e. doctors, medical students and nonmedical hospital staff, gave worse scores than other subject groups (p < 0.0005). CONCLUSION: The concept of handicap applies across cultures. Perception of severity of selected real life handicap scenarios by HK Chinese were well estimated using scale weights from UK populations developed for the London Handicap Scale. Significant differences in perception of certain handicap scenarios by different population subgroups deserve further study.

Activities of Daily Living↗
PubMed2000

A comparison of the responsiveness of the Nottingham extended activities of daily living scale, London handicap scale and SF-36.

PURPOSE: Clinical trials require scales which are sensitive to the effects of intervention. This study examined the sensitivity to change of three generic health status measurement scales commonly used in evaluations of interventions in chronic, disabling disease. METHODS: Questionnaires comprising the SF-36, London Handicap Scale and Nottingham Extended Activities of Daily Living scale were administered to 81 patients before and after hip replacement. Changes were quantified as 'effect sizes'. RESULTS: Eighty nine per cent of patients reported improvements three months after surgery. The largest changes were seen on the SF-36 pain scale (effect size 1.2 at three months, 1.5 at 6-12 months), physical function (1.1, 1.3) and role limitation--physical (0.8, 1.2) scales. The London Handicap Scale also measured large changes (effect sizes 0.6, 0.9), but the Extended Activities of Daily Living scale was insensitive to change (effect sizes 0.1, 0.2). CONCLUSIONS: Some of the SF-36 dimensions were very sensitive to change. The London Handicap Scale was also reasonably responsive, and has the advantage of being a single, utility-based, score. The simpler Extended ADL score was poorly responsive.

Activities of Daily Living↗
PubMed2000

Multiple risk factor interventions for primary prevention of coronary heart disease.

BACKGROUND: Primary prevention programmes in many countries attempt to reduce mortality and morbidity due to coronary heart disease through risk factor modification. It is widely believed that multiple risk factor intervention using counselling and educational methods is efficacious and cost-effective and should be expanded. Recent trials examining risk factor changes have cast considerable doubt on the effectiveness of these multiple risk factor interventions. OBJECTIVES: To assess the effects of multiple risk factor intervention for reducing cardiovascular risk factors, total mortality, and mortality from coronary heart disease among adults without clinical evidence of established cardiovascular disease. SEARCH STRATEGY: We searched Medline using a standard randomised trial filter. Date of the most recent search was April 1995. SELECTION CRITERIA: Intervention studies using counseling or education to modify more than one cardiovascular risk factor in adults from general populations, occupational groups, or high risk groups. Trials of less than 6 months duration were excluded. DATA COLLECTION AND ANALYSIS: Both reviewers, independently extracted data. Investigators were contacted to obtain missing information. MAIN RESULTS: A total of 18 trials were found of which 10 reported clinical event data. Net changes in systolic and diastolic blood pressure, smoking prevalence, and blood cholesterol were -3.9mmHg (95% CI -4.2,-3.6 mmHg), -2.9 mmHg (95% CI -3.1,-2.7 mmHg), -4.2% (95% CI -4.8, -3.6%), and -0.08mMol/l (95% CI -0.1.-0.06 mMol/l) respectively. In the ten trials with clinical event end-points, the pooled odds ratios for total and coronary heart disease mortality were 0.97 (95% confidence intervals (CI) 0.92-1.02) and 0.97 (95% CI 0.88-1.04) respectively. Statistical heterogeneity between the studies with respect to mortality and risk factor changes was due to trials focusing on hypertensive participants and those using considerable amounts of drug treatment. Only these trials demonstrating significant reductions in mortality. REVIEWER'S CONCLUSIONS: The pooled effects suggest multiple risk factor intervention has no effect on mortality. However, a small, but potentially important, benefit of treatment (about a 10% reduction in CHD mortality) may have been missed. Risk factor changes were relatively modest, were related to the amount of pharmacological treatment used, and in some cases may have been over-estimated because of regression to the mean effects, lack of intention to treat analyses, habituation to blood pressure measurement, and use of self-reports of smoking. Interventions using personal or family counseling and education with or without pharmacological treatments appear to be more effective at achieving risk factor reduction and consequent reductions in mortality in high risk hypertensive populations. The evidence suggests that such interventions have limited utility in the general population.

Coronary Disease↗
PubMed2000

Exercise-based rehabilitation for coronary heart disease.

BACKGROUND: The burden of cardiovascular disease world-wide is one of great concern to patients and health care agencies alike. Circulatory diseases, including myocardial infarction (MI) and stroke, kill more people than any other disease. Cardiac rehabilitation aims to restore patients who have suffered myocardial infarction to optimal health through exercise only based rehabilitation or comprehensive cardiac rehabilitation (eg. smoking cessation advice, diet and counselling as well as exercise). Data from two published and widely cited meta-analyses (Oldridge 1988, O'Connor 1989) of over 4,000 patients each have demonstrated that patients randomised to exercise-based cardiac rehabilitation after MI have a statistically significant reduction in all-cause and cardiac mortality of about 20 to 25% compared to patients receiving conventional care. However, the trials included were small and often of poor methodological quality. Incomplete literature review methods may have resulted in publication bias thereby resulting in an over-estimate of the benefit of cardiac rehabilitation. The randomised controlled trials used in the reviews have focused almost exclusively on low-risk, middle-aged males post MI, thereby excluding women and the elderly. OBJECTIVES: To determine the effectiveness of exercise only rehabilitation and exercise in addition to other rehabilitation interventions (termed comprehensive cardiac rehabilitation) compared with usual care on the mortality, morbidity, health-related quality of life (HRQoL) and modifiable cardiac risk factors of patients with coronary heart disease. SEARCH STRATEGY: Electronic databases were searched for randomised controlled trials, using standardised trial filters, from the earliest date available to December 31st 1998. SELECTION CRITERIA: Men and women of all ages, in both hospital-based and community-based settings, who have had myocardial infarction, coronary artery bypass graft or percutaneous transluminal coronary angioplasty, or who have angina pectoris or coronary artery disease defined by angiography have been included. Studies involving participants following heart transplant, heart valve surgery or heart failure have been excluded. Follow up periods of less than 6 months were excluded. DATA COLLECTION AND ANALYSIS: Studies were selected independently by two reviewers, and data extracted independently. Authors were contacted where possible to obtain missing information. MAIN RESULTS: The current systematic review has allowed analysis of an increased number of patients from approximately 4500 in the earlier meta-analyses to 7683 (2582 in exercise only and 5101 in the comprehensive cardiac rehabilitation group). The quality of reporting overall was poor, with generally high losses to follow up. The pooled effect estimate for total mortality for the exercise only intervention shows a 27% reduction in all cause mortality (random effects model OR 0.73 (0.54, 0.98)). Similarly, comprehensive cardiac rehabilitation reduced all cause mortality compared to usual care, but to a lesser degree (OR 0.87 (0.71, 1.05)). Total cardiac mortality was reduced by 31% (random effects model OR 0.69 (0.51, 0.94)) and 26% (random effects model OR 0.74 (0.57, 0.96)) in the exercise only and comprehensive cardiac rehabilitation intervention groups respectively when compared to usual care. Neither intervention had any effect on the ocurrence of non-fatal myocardial infarction. There was a significant net reduction in total cholesterol in the comprehensive cardiac rehabilitation group (pooled WMD random effects model -0.57 mmol/l (-0.83, -0.31)), but not the exercise only rehabilitation group. Similarly, LDL was significantly reduced in the comprehensive cardiac rehabilitation group (pooled WMD random effects model -0.51 mmol/l (-0.82, -0.19). The effect of exercise only rehabilitation or comprehensive cardiac rehabilitation interventions on revascularisation rates, blood pressure or smoking behaviour could not be determined by this meta-analysis due to the small number of trials reporting these outcomes and heterogeneity between trials. It was not possible to combine the data from studies reporting HRQoL as an outcome. Eighteen different instruments were used to assess HRQoL in the 11 studies reporting it as an outcome. The data are presented qualitatively, only one trial reporting significant improvements with the intervention. REVIEWER'S CONCLUSIONS: Exercise-based cardiac rehabilitation appears to be effective in reducing cardiac deaths but the evidence base is weakened by poor quality trials. It is not clear from this review whether exercise only or a comprehensive cardiac rehabilitation intervention is more beneficial. The population studied in this review is still predominately male, middle aged and low risk. Identification of the ethnic origin of the participants was seldom reported. (ABSTRACT TRUNCATED)

Coronary Disease↗
PubMed2000

Reduced or modified dietary fat for prevention of cardiovascular disease.

BACKGROUND: Reduction or modification of dietary fat can improve total cholesterol levels, but may also have a variety of effects, both positive and negative, on other cardiovascular risk factors. OBJECTIVES: The aim of this systematic review was to assess the effect of reduction or modification of dietary fats on total and cardiovascular mortality and cardiovascular morbidity over at least 6 months, using all available randomized clinical trials. SEARCH STRATEGY: The Cochrane Library, MEDLINE, EMBASE, CAB Abstracts, CVRCT registry and related Cochrane Groups' trial registers were searched through spring 1998, SIGLE to January 1999. Trials known to experts in the field and biographies were included through May 1999. SELECTION CRITERIA: Trials fulfilled the following criteria: 1) randomized with appropriate control group, 2) intention to reduce or modify fat or cholesterol intake (excluding exclusively omega-3 fat interventions), 3) not multi factorial, 4) healthy adult humans, 5) intervention at least six months, 6) mortality or cardiovascular morbidity data available. Inclusion decisions were duplicated, disagreement resolved by discussion or a third party. DATA COLLECTION AND ANALYSIS: Rate data were extracted by two independent reviewers and meta-analysis performed using random effects methodology. Meta-regression and funnel plots were used. MAIN RESULTS: Twenty seven studies were included (40 intervention arms, 30,901 person-years). There was no significant effect on total mortality (rate ratio 0.98, 95% CI 0.86 to 1.12), a trend towards protection form cardiovascular mortality (rate ratio 0.91, 95% CI 0. 77 to 1.07), and significant protection from cardiovascular events (rate ratio 0.84, 95% CI 0.72 to 0.99). The latter became non-significant on sensitivity analysis. Trials where participants were involved for more than 2 years showed significant reductions in the rate of cardiovascular events and a suggestion of protection from total mortality. The degree of protection from cardiovascular events appeared similar in high and low risk groups, but was statistically significant only in the former. REVIEWER'S CONCLUSIONS: The findings are suggestive of a small but potentially important reduction in cardiovascular risk in trials longer than two years. Lifestyle advice to all those at high risk of cardiovascular disease (especially where statins are unavailable or rationed), and to lower risk population groups, should continue to include permanent reduction of dietary saturated fat and partial replacement by unsaturates.

Cardiovascular Diseases↗
PubMed2000

Femoral atherosclerosis in an older British population: prevalence and risk factors.

Most estimates of the prevalence of peripheral atherosclerosis have been based on intermittent claudication or lower limb blood flow. The aim of this study was therefore to determine the prevalence of underlying femoral plaque, and to determine its association with other cardiovascular disease and risk factors. Presence of plaque was identified using ultrasound in a random sample of men (n=417) and women (n=367) aged 56-77 years. Coexistent cardiovascular disease, exercise and smoking were determined by questionnaire, blood pressure was recorded, and serum cholesterol and plasma fibrinogen were determined. Of the 784 subjects that were scanned, 502 (64%) demonstrated atherosclerotic plaque. Disease prevalence increased significantly with age (P<0.0001), and was more common in men (67.1 vs. 59.4%, P<0.05). Subjects with femoral plaque had a significantly greater odds of previous ischaemic heart disease (OR 2. 2, 95% CI 1.3, 3.7) and angina (OR 1.7, 95% CI 1.03, 2.7), but not of stroke or leg pain on exercise. Current and ex-smoking, raised serum total cholesterol and plasma fibrinogen levels, but not blood pressure, were associated with an increased risk of femoral plaque, independent of age and sex. Frequent exercise and a high HDL cholesterol were significantly associated with lower risk. In conclusion, therefore, atherosclerotic disease of the femoral artery affects almost two-thirds of the population in late middle age. It is associated with an increased prevalence of ischaemic heart disease and angina, but whether detecting at risk individuals using ultrasound offers advantages over simpler and less expensive risk factor scoring requires evaluation in trials.

Age Distribution↗
PubMed2000

Rhetoric and reality in stroke patient care.

The aim of this study was to identify aspects of the process of care that might help explain the improved outcomes associated with stroke units. Three different care settings for stroke patients, an elderly care unit and general medical ward in an inner-city teaching hospital and a stroke unit in another teaching hospital in the same city, were compared using non-participant observational methods. Nurses on the stroke unit and general medical ward usually engaged in standardised and functional interaction with patients, while nurses on the elderly care unit were observed to adopt a more personal and attentive approach with patients. Rehabilitation nursing was rarely observed on the stroke unit, never on the general medical ward but always on the elderly care unit. There was evidence of effective communication between nurses and therapists on the elderly care unit but this was not observed on the stroke unit. On the elderly care unit the team appeared divided, with therapists and nurses on one side and medicine on the other, while on the stroke unit the divide was between doctors and therapists on one hand and nurses the other. On the general medical ward there was no team working. The observed lack of rehabilitation nursing, nurses' disengagement from the team and nurses' observed lack of warmth towards patients on the stroke unit were all surprising findings. Further research needs to examine whether such findings would be reproduced in stroke units elsewhere. If so, it might be that the better outcomes achieved on stroke units are despite rather than because of the nursing they receive there.

Aged↗