Objectives: To assess the mortality rate (MR) and the mortality risk of a rheumatoid arthritis (RA) inception cohort, with and without biologic agents (BAs). Other factors associated to mortality were also investigated.
Methods: Retrospective longitudinal study of RA patients, attending the rheumatology outpatient clinic of a tertiary Hospital (Madrid), collected over 5 years (2000-2004), and followed from the diagnosis of RA up to the patients' death, lost to follow-up or September 2013. The dependent variable was death and the independent variable was exposure to BAs. Covariables: sociodemographic, clinical and therapy variables. MR was expressed per 1,000 patient-years with the 95% confidence interval [CI]. BA influence on MR was analysed by multivariable Cox models. Clinical and therapy variables were used in a time-dependent manner. The results are expressed in hazard ratio (HR) and [CI].
Results: We included 576 patients and 711 courses of therapy. 19.6% were taking BA, 86% disease-modifying anti-rheumatic drugs (DMARDs) (70% on methotrexate - MTX), and 12% were untreated. There were 133 deaths during 4,981.64 patient-years at risk. The MR for BA was 12.6 [6-26], for DMARDs was 22.3 [18.4-27.1], and for those without treatment was 89.1 [61.9-128.2]. The adjusted HR for mortality in those exposed to BA versus those not exposed was 0.75 [0.32-1.71]). Other variables independently associated with mortality were: age, rheumatoid factor, hospital admissions, Health Assessment Questionnaire (HAQ), and MTX use (HR: 0.44 [0.29-0.66]).
Conclusions: BAs and standard DMARDs are more effective in decreasing mortality compared to no therapy. Patients exposed to Bas were not associated with a significant increase or decrease in mortality when compared to patients with non-biological DMARDs. The use of MTX remains the only drug that has independently shown a beneficial effect on mortality.