Medication use in systemic lupus erythematosus

To evaluate factors affecting therapeutic approaches used in clinical practice for the management of systemic lupus erythematosus (SLE), in a multicenter cohort.

We combined data from 10 clinical adult SLE cohort registries in Canada. We used multivariate generalized estimating equation methods to model dichotomized outcomes, running separate regressions where the outcome was current exposure of the patient to specific medications. Potential predictors of medication use included demographic (baseline age, sex, residence, race/ethnicity) and clinical factors (disease duration, time-dependent damage index scores, and adjusted mean SLE Disease Activity Index-2K scores). The models also adjusted for clustering by center.

Higher disease activity and damage scores were each independent predictors of exposure to nonsteroid immunosuppressive agents, and for exposure to prednisone. This was not definitely demonstrated for antimalarial agents. Older age at diagnosis was independently and inversely associated with exposure to any of the agents studied (immunosuppressive agents, prednisone, and antimalarial agents). An additional independent predictor of prednisone exposure was black race/ethnicity (adjusted RR 1.46, 95% CI 1.18, 1.81). For immunosuppressive exposure, an additional independent predictor was race/ethnicity, with greater exposure among Asians (RR 1.39, 95% CI 1.02, 1.89) and persons identifying themselves as First Nations/Inuit (2.09, 95% CI 1.43, 3.04) than among whites. All of these findings were reproduced when adjustment for disease activity was limited to renal involvement.

Ours is the first portrayal of determinants of clinical practice patterns in SLE, and offers interesting real-world insights. Further work, including efforts to determine how differing clinical approaches may influence outcome, is in progress.