Abstract: 【Abstract】 Objective To investigate the epidemiological characteristics of newly diagnosed leprosy patients in Chongqing, and to evaluate the efficacy of different multidrug therapy （MDT） regimens and factors associated with treatment outcomes. Methods A retrospective cohort study was conducted. Based on the National Leprosy Control Management Information System, 216 newly diagnosed leprosy patients were included from three regional designated hospitals （Hospitals of Dermatology Prevention and Treatment in Banan District, Wanzhou District, and Nanchuan District） in Chongqing between 2007 and 2020. Baseline information, treatment regimens, and follow-up data during and after treatment were collected. All patients received MDT （rifampicin, dapsone, and clofazimine）, and were divided into a 1-year MDT group and a 2-year MDT group based on the treatment duration. Descriptive statistics were used to analyze epidemiological characteristics; the Wilcoxon rank-sum test, Pearson's chi-square test, or Fisher's exact test was used to compare treatment outcomes between groups. The treatment outcome was categorized into two grades, i.e., favorable and moderate, and a logistic regression model was employed to analyze factors influencing efficacy. Results A total of 216 patients were included, comprising 156 males （72.2%） and 60 females （27.8%）, aged 13 to 100 years; these patients were from 35 districts and counties in Chongqing, and predominantly located in the urban clusters in the Three Gorges Reservoir Area in northeast Chongqing （88 cases, 40.7%）; most patients were farmers （187 cases, 86.6%）, and had education levels of junior high school or below （196 cases, 90.7%）. From 2007 to 2020, the number of reported cases （27 cases, 12.5%） in 2008 was the largest; the median diagnostic delay for leprosy was 781 days. Among the 216 patients, 119 （55.1%） underwent 1-year MDT, while 97 （44.9%） received 2-year MDT. The incidence of leprosy reactions during treatment was higher in the 1-year MDT group than in the 2-year MDT group （27.7% ［33/119］ vs. 15.5% ［15/97］, χ2 = 4.65, P = 0.031）, while the incidence of disability aggravation at the end of treatment was lower in the 1-year MDT group than in the 2-year MDT group （4.2% ［5/119］ vs. 13.4% ［13/97］, χ2 = 5.92, P = 0.015）. There was no significant difference in the proportion of patients achieving favorable or moderate outcomes between the two groups （χ2 = 0.55, P = 0.458）. Multivariate logistic regression analysis revealed that patients without leprosy reactions before treatment were 3.95 times more likely to achieve a favorable outcome than those with leprosy reactions before treatment （OR = 3.95, 95% CI: 1.97 - 8.22, P < 0.001）. Conclusions Leprosy patients in Chongqing were predominantly middle-aged and elderly farmers in remote areas. The therapeutic efficacy of 1-year MDT appeared comparable to that of 2-year MDT. Absence of leprosy reactions prior to treatment was associated with a higher likelihood of achieving favorable treatment outcomes.

Key words: Leprosy, MDT, Effectiveness evaluation, Leprosy reaction, Chongqing, Treatment course