Statin discontinuation and risk of acute myocardial infarction in patients with rheumatoid arthritis: a population-based cohort study
- Mary A De Vera1,2,
- Hyon Choi1,3,
- Michal Abrahamowicz4,
- Jacek Kopec1,2,
- Maria Victoria Goycochea-Robles1,5,
- Diane Lacaille1,6,7
- 1Arthritis Research Centre of Canada, Vancouver, Canada
- 2School of Population and Public Health, University of British Columbia, Vancouver, Canada
- 3Boston University School of Medicine, Section of Rheumatology and the Clinical Epidemiology Unit, Boston, Massachusetts, USA
- 4Department of Epidemiology & Biostatistics, McGill University, Montreal, Canada
- 5Research Unit of Clinical Epidemiology, Hospital Regional 1 IMSS, Mexico City, Mexico
- 6Rheumatology Division, Department of Medicine, Faculty of Medicine, University of British Columbia, Vancouver, Canada
- 7Department of Experimental Medicine, Faculty of Medicine, University of British Columbia, Vancouver, Canada
- Correspondence to Mary De Vera, University of British Columbia School of Population & Public Health, Arthritis Research Centre of Canada, 895 W. 10th Avenue, Vancouver, BC, Canada V5Z 1L7;
- Accepted 23 January 2011
- Published Online First 6 March 2011
Objectives Screening for cardiovascular risk factors and treating hyperlipidaemia with statins are recommended to reduce the increased cardiovascular risk in individuals with rheumatoid arthritis (RA). However, poor compliance with statins may limit their therapeutic benefit. Our objective was to evaluate the impact of statin discontinuation on risk of acute myocardial infarction (AMI) among RA patients.
Methods The authors conducted a population-based cohort study of RA patients with incident statin use followed from May 1996 to March 2006 using administrative health data. Primary exposure was statin discontinuation for ≥3 months at any time during therapy course. The authors used Cox's proportional hazards models and modelled statin discontinuation as a time-dependent variable, while adjusting for age, sex, comorbidities, use of other medications influencing cardiac risk, and proxy indicators of RA severity.
Results During 15 669 person-years of follow-up in 4102 incident-statin users with RA, the authors identified 264 AMI events. Statin discontinuation was associated with 67% increased risk of AMI (adjusted HR 1.67; 95% CI 1.24 to 2.25). There was a 2% increase in risk of AMI with each 1-month increase in the duration of discontinuation (adjusted HR 1.02; 95% CI 1.01 to 1.03). These associations were not modified by timing of first statin prescription, prior AMI status, sex and age (p values for interactions >0.17).
Conclusions These population-based data indicate that RA patients who discontinue statins have increased risk of AMI. Findings emphasise the need to raise awareness, among health professionals and people with RA, of the importance of compliance with statin therapy in RA.
Funding This research was supported from an operating grant from the Canadian Institutes of Health Research (CIHR grant number MOP 77605).
Competing interests MAdeV received doctoral training support from the Canadian Institutes of Health Research, the Canadian Arthritis Network/The Arthritis Society of Canada, and the Michael Smith Foundation for Health Research. MA is a James McGill Professor of Biostatistics at McGill University. VG-R's postdoctoral fellowship was supported by Consejo Nacional de Ciencia y Tecnología (CONACYT). DL holds an Investigator Award from The Arthritis Society of Canada and is the Nancy and Peter Paul Saunders Scholar.
Ethics approval This study was conducted with the approval of the University of British Columbia Behavioural Research Ethics Board.
Patient consent Obtained.
Provenance and peer review Not commissioned; externally peer reviewed.