Background Disease activity and inflammation are established predictors of increased mortality in patients with rheumatoid arthritis (RA).
Objectives To investigate whether osteoporosis and use of calcium supplementationswere associated with death from cardiovascular disease in RA.
Methods Patients in the Oslo RA register (ORAR) were examined and BMD measured in 1996. Biomarkers were analysed consecutively. A trained study-nurse recorded patient medication and assessed 28-tender and 28-swollen joint counts. Disease activity was calculated as DAS28. The cohort was linked to the Norwegian Cause of Death registry on Dec 31st, 2010, and we examined all-cause mortality as well as death from cardiovascular disease (Primary cause of death: Acute myocardial infarction, angina, atherosclerotic heart disease, hypertension, cerebral infarction, heart failure or stroke)
We analysed all-cause mortality and death from CVD as endpoints in separate Cox regression models with hazard ratio (HR) and 95% confidence intervals (95% CI). Initially, baseline variables were analysed separately, adjusted for age and sex. Variables with a p-value of ≤0.1 were then included into a multivariable model and further excluded using backwards selection with a cut-of p-value of 0.05. Robustness of the final model was assessed by re-entering excluded variables.
Results 609 patients, mean 53.6 years (range 20-70) were examined in 1996/1997. During the period of observation 162 patients had died, while 447 were still alive at time of censoring, 7414 observed patient-years. In 43 (7%) patients CVD was the primary cause of death. Results from the univariate analyses in are presented in the table. In the final multivariate model of all-cause mortality; increased baseline ESR (HR 1.02, 95% CI 1.01-1.03 p<0.001), calcium supplementation (1.68, 1.07-2.62 p=0.02) and osteoporosis (1.56,1.07-2.29 p=0.02) remained associated with higher mortality. In the final multivariate model of death from CVD; increased ESR (1.03, 1.01-1.04 p<0.001) and calcium supplementation (3.03, 1.49-6.15 p=0.002) remained associated with higher mortality.
Conclusions Increased baseline inflammation and calcium supplementation were associated with increased all-cause mortality and risk of primary atherosclerotic death in this longitudinal study of a representative cohort of RA patients.
Disclosure of Interest None declared