Adherence to antimalarial therapy can provide a protective effect against the development of type 2 diabetes in patients with systemic lupus erythematosus (SLE), according to study results published in Arthritis Care & Research.

Researchers conducted a retrospective longitudinal cohort study of adults with incident SLE who used antimalarial medication between 1996 and 2012 to evaluate the association between antimalarial therapy and type 2 diabetes risk in this patient population. Data were collected from Population Data British Columbia, a Canadian administrative health resource.

The total study cohort included 1498 patients with SLE (90.8% women; mean age, 44.4±14.8 years). Over the follow-up period, the mean number of antimalarial prescriptions was 23.2±37.7, with a mean of 2.1±1.8 courses of therapy. Mean course duration for these treatments was 553.9±820.8 days. The investigators noted 140 incident cases of type 2 diabetes over a median of 4.6 years of follow-up.

After adjusting for age, sex, comorbidities, and concomitant medication use, the hazard ratio for developing type 2 diabetes among adherent patients was 0.61 (95% CI, 0.40-0.93) compared with patients who discontinued medication use. The adjusted hazard ratio for nonadherent patients was 0.78 (95% CI, 0.50-1.22) compared with patients who discontinued use.

Further sensitivity analyses focusing on permutations of permissible gaps and cutoffs for proportion of days covered by medication did not change the results.

Study limitations included vulnerabilities associated with the use of administrative data, including diagnostic uncertainty or misclassification.

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“Adherent patients were 39% less likely to develop [type 2 diabetes] compared to those who discontinued their therapy,” the researchers wrote. “Our findings also suggest that when taking less than 90% of the prescribed doses of antimalarials, the protective effect against [type 2 diabetes] is lost.”

“Our findings should be used to emphasize the importance of medication adherence in not only treating SLE, but also preventing its complications,” they concluded.

Reference

Salmasi S, Sayre EC, Avina-Zubieta JA, Esdaile JM, De Vera MA. Adherence to antimalarial therapy and risk of type 2 diabetes mellitus among patients with systemic lupus erythematosus: a population-based study [published online January 21, 2020]. Arthritis Care Res. doi:10.1002/acr.24147