Arthritis & Rheumatism, Volume 62,
November 2010 Abstract Supplement
Abstracts of the American College of
Rheumatology/Association of Rheumatology Health Professionals
Annual Scientific Meeting
Atlanta, Georgia November 6-11, 2010.
Independent Impact of Statin Discontinuation on Mortality in Patients with Rheumatoid Arthritis: A Population-Based Study.
De Vera1, Mary A., Choi3, Hyon K., Abrahamowicz2, Michal, Kopec1, Jacek, Lacaille1, Diane V.
Discontinuation of statin therapy is common and associated with increased risk of mortality in the general population, but no corresponding data are available among individuals with rheumatoid arthritis (RA). Since cardiovascular diseases (CVD) are the primary cause of excess mortality in RA, RA-specific data are highly relevant to clinical care of RA. Our objective was to evaluate the impact of statin discontinuation on risk of mortality in individuals with RA.
We conducted a population-based cohort study of RA patients with incident statin use followed from May 1996 to March 2006 with administrative health data. Exposure was statin discontinuation for >=3 months at any time during follow-up, measured both as a categorical (y/n) and continuous (time since discontinuation) variable. Primary outcome was death due to all CVD and secondary outcome was death due to all causes. We used Cox's proportional hazards analyses, modeling statin discontinuation as a time-dependent dichotomous variable updated every month and in separate analyses, as a continuous time-dependent variable that increased with every month since discontinuation. Factors known to influence statin discontinuation, CVD, or mortality were considered as covariates, including age, gender, comorbidities (acute myocardial infarction, cerebrovascular accidents, malignancy, infections, chronic obstructive pulmonary disease, gastrointestinal diseases, renal failure, angina, use of diabetes, hypertension, and congestive heart failure medications), and use of medications known to influence cardiac risk (hormone replacement therapy, anticoagulants), all measured at baseline. As well, markers of RA severity (RA medication use [DMARDs, glucocorticosteroids, NSAIDs, methotrexate] and rate of RA-related medical visits) were included as time-dependent covariates. Established risk factors for mortality in RA (e.g., AMI, malignancy) were forced into multivariable models and for putative risk factors, a forward selection procedure with p <=0.20 criterion for entry, was used.
The cohort of RA patients with incident statin use included 4,102 individuals with 16,144 person-years of follow-up (60% females; mean age 66 years). We documented 467 deaths overall with 198 due to CVD. Statin discontinuation was associated with a 60% increased risk of CVD mortality (adjusted hazard ratio [HR]=1.60 [95%CI=1.152.23]). When we modeled statin discontinuation as a continuous time-dependent variable, we found that with each additional month of discontinuation, the risk of CVD mortality was increased by 0.4% (adjusted HR=1.004 [95%CI=1.0011.016]). We found similar increased risks associated with statin discontinuation in analyses of all cause mortality outcomes (adjusted HR [statin discontinuation as a dichotomous variable]: 1.79 [95%CI=1.462.20]; adjusted HR [statin discontinuation as continuous variable]: 1.010; 95%CI=1.0021.015]).
These population-based data indicate that RA patients who discontinue statins have a higher risk of death from cardiovascular diseases and from all causes. Findings emphasize the importance of compliance with statin therapy in RA.
To cite this abstract, please use the following information:
De Vera, Mary A., Choi, Hyon K., Abrahamowicz, Michal, Kopec, Jacek, Lacaille, Diane V.; Independent Impact of Statin Discontinuation on Mortality in Patients with Rheumatoid Arthritis: A Population-Based Study. [abstract]. Arthritis Rheum 2010;62 Suppl 10 :72