Sociodemographic variations in the contribution of secondary drug prevention to stroke survival at middle and older ages: cohort studyBMJ 2009; 338 doi: https://doi.org/10.1136/bmj.b1279 (Published 16 April 2009) Cite this as: BMJ 2009;338:b1279
- Rosalind Raine, professor of health care evaluation1,
- Wun Wong, honorary research fellow1,
- Gareth Ambler, lecturer2,
- Sarah Hardoon, statistician3,
- Irene Petersen, statistician3,
- Richard Morris, reader3,
- Mel Bartley, professor of medical sociology1,
- David Blane, professor of medical sociology4
- 1Department of Epidemiology and Public Health, University College London, London WC1E 6BT
- 2Department of Statistical Science, University College London and University College London/Hospital Biomedical Research Unit
- 3Department of Primary Care and Population Health, Royal Free and University Medical School, London
- 4Department of Primary Care and Social Medicine, Imperial College London
- Correspondence to: R Raine
- Accepted 16 January 2009
Objectives To determine the extent to which secondary drug prevention for patients with stroke in routine primary care varies by sex, age, and socioeconomic circumstances, and to quantify the effect of secondary drug prevention on one year mortality by sociodemographic group.
Design Cohort study using individual patient data from the health improvement network primary care database.
Participants 12 830 patients aged 50 or more years from 113 general practices who had a stroke between 1995 and 2005 and who survived the first 30 days after the stroke.
Main outcome measures Multivariable associations between odds of receiving secondary prevention after a stroke, and sex, age group, and socioeconomic circumstances; hazard ratios for all cause mortality from 31 days after the stroke and within the first year among patients receiving treatment and by social group; and probabilities of one year mortality for social factors of interest and treatment.
Results Only 25.6% of men and 20.8% of women received secondary prevention. Receipt of secondary prevention did not vary by socioeconomic circumstances or by sex. Older patients were, however, substantially less likely to receive treatment. The adjusted odds ratio for 80-89 year olds compared with 50-59 year olds was 0.53 (95% confidence interval 0.41 to 0.69). This was because older people were less likely to receive lipid lowering drugs—for example, the adjusted odds ratio for 80-89 year olds compared with 50-59 year olds was 0.44 (95% confidence interval 0.33 to 0.59). Secondary prevention was associated with a 50% reduction in mortality risk (adjusted hazard ratio 0.50, 95% confidence interval 0.42 to 59). On average, mortality within the first year was 5.7% for patients receiving treatment compared with 11.1% for patients not receiving treatment. There was little evidence that the effect of treatment differed between the social groups examined.
Conclusion Under-treatment among older people with stroke in routine primary care cannot be justified given the lack of evidence on variations in effectiveness of treatment by age.
We thank the Longevity Steering Group for their valuable advice, comments, and support for this research, particularly John Bunker (University College London), Richard Wilkinson (University of Nottingham), Joseph Lu and Richard Humble (Legal and General), and Richard Willets (Willets Consulting); Martin Brown and Kate Walters (University College London) for their expert clinical input; and Mary Thompson (EPIC), Louise Marston (University College London), Andrew Hutchings (London School of Hygiene and Tropical Medicine), and Charlotte Ashton (Wandworth Primary Care Trust) for their advice.
Contributors: The idea for the research originated at the Longevity Steering Group (of which RR,MB, DB, are members). The study was led by RR, who is guarantor for the paper. RR, GA, SH, IP, RM, MB, and DB participated in the study design and analysis and interpretation of results. GA and SH led the statistical analysis. WW undertook the analysis. All authors drafted the article and approved the final version.
Funding: RR is partly funded by a National Institute for Health Research public health career scientist award and by the National Institute for Health Research University College London Hospital/University College London Comprehensive Biomedical Research Centre. WW is funded by Legal and General Group. The research was funded in part by the actuarial profession (Institute of Actuaries in England and Wales and the Faculty of Actuaries in Scotland). The authors’ work was independent of the funders.
Competing interests: None declared.
Ethical approval: This study was approved by the London research ethics committee, National Research Ethics Service (07/MRE02/19).
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