P084 Risk factors for chronic and recurrent erythema nodosum leprosum: a retrospective cohort study

Abstract

Erythema nodosum leprosum (ENL) increases leprosy morbidity. About 39–77% of patients with ENL experience multiple episodes; however, risk factors for chronic and/or recurrent ENL have not been well studied. Our aim was to identify risk factors for chronic or recurrent ENL in patients with borderline lepromatous (BL) and lepromatous (LL) leprosy. This was a retrospective cohort study including patients with BL or LL leprosy attending our leprosy clinic over a 5-year period. Patients were classified as having steroid-dependent ENL if they were treated with oral prednisolone for > 12 weeks or required addition of a steroid-sparing immunomodulator. Steroid-dependent ENL could be either chronic (single episode > 24 weeks) or recurrent (> 4 episodes in a year). The following variables were selected a priori as risk factors: age at leprosy diagnosis, sex, leprosy duration, leprosy spectrum, baseline bacteriological index (BI), treatment status and number of enlarged nerves. The outcomes analysed were developing ENL (vs. not developing it) and developing steroid-dependent recurrent or chronic ENL (vs. acute ENL). Of the 1029 files of patients with leprosy available for review, 535 (52.0%) were in the BL/LL leprosy spectrum. Overall, 160 (30.0%) of these patients had ENL (57, 35.6% with acute ENL and 103, 64.4% with chronic or recurrent ENL). Younger age at leprosy diagnosis (33.8 vs. 38.8 years, P < 0.001), BI > 2 [odds ratio (OR) 2.6, 95% confidence interval (CI) 1.5–4.4, P < 0.001) and LL leprosy (OR 3.5, 95% CI 2.2–5.7, P < 0.001) were independently associated with developing ENL, while patients who had completed the multidrug therapy course (OR 6.3, 95% CI 1.4–29.5, P = 0.02) were more likely to have chronic or recurrent ENL. There were no statistically significant differences for other variables between the groups with and without ENL, and with acute vs. chronic or recurrent ENL. About two-thirds of our patients with ENL had recurrent or chronic episodes. Treating patients with ENL with longer multidrug therapy courses may reduce the risk of chronic or recurrent ENL.