ABSTRACT: To compare the social and demographic profiles of patients who receive statin treatment after myocardial infarction and patients included in randomised trials. To estimate the effect of statin use in community based patients on subsequent all cause mortality and cardiovascular recurrence, contrasting effects with trial patients.
Observational cohort study using a record linkage database.
Tayside, Scotland (population size and characteristics: about 400,000, mixed urban and rural).
4892 patients were discharged from hospital after their first myocardial infarction between January 1993 and December 2001. 2463 (50.3%) were taking statins during an average follow-up of 3.7 years (3.1% in 1993 and 62.9% in 2001).
All cause mortality and recurrence of cardiovascular events.
319 deaths occurred in the statin treated group (age adjusted rate 4.1 per 100 person years, 95% confidence interval 3.2 to 4.9), and 1200 in the statin untreated group (12.7 per 100 person years, 11.1 to 14.3). More older people and women were represented in the population of patients treated with statins than among those recruited into clinical trials (mean age 67.8 v 59.8; women 39.6% v 16.9%, respectively). The effects of statins in routine clinical practice were consistent with, and similar to, those reported in clinical trials (adjusted hazard ratio for all cause mortality 0.69, 95% confidence interval 0.59 to 0.80; adjusted hazard ratio for cardiovascular recurrence 0.82, 0.71 to 0.95).
The community effectiveness of statins in those groups that were not well represented in clinical trials was similar to the efficacy of statins in these trials.
BMJ (Clinical research ed.). 05/2005; 330(7495):821.
BMJ (Clinical research ed.). 08/2004; 329(7456):31-4.
ABSTRACT: To assess the long term effects of advice to restrict dietary sodium in adults with and without hypertension.
Systematic review and meta-analysis of randomised controlled trials.
Cochrane library, Medline, Embase, and bibliographies.
Unconfounded randomised trials that aimed to reduce sodium intake in healthy adults over at least 6 months. Inclusion decisions, validity and data extraction were duplicated. Random effects meta-analysis, subgrouping, sensitivity analysis, and meta-regression were performed.
Mortality, cardiovascular events, blood pressure, urinary sodium excretion, quality of life, and use of antihypertensive drugs.
Three trials in normotensive people (n=2326), five trials in those with untreated hypertension (n=387), and three trials in people being treated for hypertension (n=801) were included, with follow up from six months to seven years. The large high quality (and therefore most informative) studies used intensive behavioural interventions. Deaths and cardiovascular events were inconsistently defined and reported. There were 17 deaths, equally distributed between intervention and control groups. Systolic and diastolic blood pressures were reduced (systolic by 1.1 mm Hg, 95% confidence interval 1.8 to 0.4 mm Hg; diastolic by 0.6 mm Hg, 1.5 to -0.3 mm Hg) at 13 to 60 months, as was urinary 24 hour sodium excretion (by 35.5 mmol/24 hours, 47.2 to 23.9). Degree of reduction in sodium intake and change in blood pressure were not related.
Intensive interventions, unsuited to primary care or population prevention programmes, provide only small reductions in blood pressure and sodium excretion, and effects on deaths and cardiovascular events are unclear. Advice to reduce sodium intake may help people on antihypertensive drugs to stop their medication while maintaining good blood pressure control.
BMJ (Clinical research ed.). 10/2002; 325(7365):628.
ABSTRACT: To assess the characteristics of medical research that is press released by general medical journals and reported in newspapers.
All original research articles published in Lancet and BMJ during 1999 and 2000.
Inclusion of articles in Lancet or BMJ press releases, and reporting of articles in Times or Sun newspapers.
Of 1193 original research articles, 517 (43%) were highlighted in a press release and 81 (7%) were reported in one or both newspapers. All articles covered in newspapers had been press released. The probability of inclusion in press releases was similar for observational studies and randomised controlled trials, but trials were less likely to be covered in the newspapers (odds ratio 0.15 (95% confidence interval 0.06 to 0.37)). Good news and bad news were equally likely to be press released, but bad news was more likely to be reported in newspapers (1.74 (1.07 to 2.83)). Studies of women's health, reproduction, and cancer were more likely to be press released and covered in newspapers. Studies from industrialised countries other than Britain were less likely to be reported in newspapers (0.51 (0.31 to 0.82)), and no studies from developing countries were covered.
Characteristics of articles were more strongly associated with selection for reporting in newspapers than with selection for inclusion in press releases, although each stage influenced the reporting process. Newspapers underreported randomised trials, emphasised bad news from observational studies, and ignored research from developing countries.
BMJ (Clinical research ed.). 08/2002; 325(7355):81-4.
ABSTRACT: Biases in systematic reviews and meta-analyses may be examined in 'meta-epidemiological' studies, in which the influence of trial characteristics such as measures of study quality on treatment effect estimates is explored. Published studies to date have analysed data from collections of meta-analyses with binary outcomes, using logistic regression models that assume that there is no between- or within-meta-analysis heterogeneity. Using data from a study of publication bias (39 meta-analyses, 394 published and 88 unpublished trials) and language bias (29 meta-analyses, 297 English language trials and 52 non-English language trials), we compare results from logistic regression models, with and without robust standard errors to allow for clustering on meta-analysis, with results using a 'meta-meta-analytic' approach that can allow for between- and within-meta-analysis heterogeneity. We also consider how to allow for the confounding effects of different trial characteristics. We show that both within- and between meta-analysis heterogeneity may be of importance in the analysis of meta-epidemiological studies, and that confounding exists between the effects of publication status and trial quality.
Statistics in Medicine 07/2002; 21(11):1513-24. · 1.88 Impact Factor
ABSTRACT: Excluding clinical trials reported in languages other than English from meta-analyses may introduce bias and reduce the precision of combined estimates of treatment effects. We examined the influence of trials published in languages other than English on combined estimates and conclusions of published meta-analyses.
We searched journals and the Cochrane Database of Systematic Reviews for meta-analyses of at least five trials with binary outcomes that were based on comprehensive literature searches without language restrictions. We compared estimates of treatment effects from trials published in languages other than English to those from trials published in English, and assessed the impact of restricting meta-analyses to trials published in English.
We identified 303 meta-analyses: 159 (52.4%) employed comprehensive literature searches of which 50 included 485 English and 115 non-English language trials. Non-English language trials included fewer participants (median 88 versus 116, P = 0.006) and were more likely to produce significant results at P < 0.05 (41.7% versus 31.3%, P = 0.033). The methodological quality of non-English language trials tended to be lower than that of trials published in English. Estimates of treatment effects were on average 16% (95% CI : 3-26%) more beneficial in non-English-language trials than in English-language trials. In 29 (58.0%) meta-analyses the change in effect estimates after exclusion of non-English language trials was less than 5%. In the remaining meta-analyses, 5 (10.0%) showed more benefit and 16 (32.0%) less benefit after exclusion of non-English language trials.
This retrospective analysis suggests that excluding trials published in languages other than English has generally little effect on summary treatment effect estimates. The importance of non-English language trials is, however, difficult to predict for individual systematic reviews. Comprehensive literature searches followed by a careful assessment of trial quality are required to assess the contribution of all relevant trials, independent of language of publication.
International Journal of Epidemiology 03/2002; 31(1):115-23. · 6.41 Impact Factor