Factors associated with timing of lepra reactions in a cohort from 2008 to 2016 in Rondônia, Amazon Region, Brazil

The clinical management of leprosy patients poses a specific challenge, namely lepra reactions. This non-concurrent cohort study aimed to analyze the timing of the first lepra reaction during and after polychemotherapy (PCT) and associated factors. A total of 1,621 patients were assessed (PB = 8.9% and MB = 91.1%) from 2008 to 2016, reported to the System of Reaction States in Leprosy (SisReação/RO) database. Reactions occurred predominantly during PCT (997; 61.5%) and less frequently only after PCT (624; 38.5%). Earliness of the reaction after diagnosis was analyzed with Kaplan-Meier survival curves, with comparison between the PB and MB groups using the Mantel-Cox log-rank test. Univariate and multivariate Cox regression models were constructed to identify factors associated with occurrence of lepra reactions (hazard ratio) and the corresponding 95%CI. The multivariate model included variables with p-values < 0.20 in the univariate analysis. PB patients developed reactions earlier than MB patients. Other characteristics were associated with earlier reactions: female gender and negative smear microscopy. In the aggregate period (during and after PCT), PB presented 24% higher risk of lepra reaction than MB patients, and negative smear microscopy increased this risk by 40% compared to positive smear microscopy. During and after PCT, PB presented 1.3 and 1.6 times the risk, respectively, of reactions when compared to MB patients. We thus recommend prioritizing surveillance of lepra reactions during and after PCT as measures to prevent physical disabilities and to improve quality of life for persons with leprosy.

Keywords:
Leprosy; Epidemiologic Surveillance; Survival Analysis