Epidemiologic Correlates of Mortality among Symptomatic Visceral Leishmaniasis Cases: Findings from Situation Assessment in High Endemic Foci in India

BackgroundVisceral leishmaniasis (VL) is highly prevalent in the Indian state of Bihar and, without proper diagnosis and treatment, is associated with high fatality. However, lack of efficient reporting mechanism had been an impediment in estimating the burden of mortality and its antecedents among symptomatic VL cases. The objectives of the current study were to generate a reliable estimate of symptomatic VL caseload and mortality in Bihar, as well as to identify the epidemiologic and health infrastructure-related predictors of VL mortality.Methodology and Principal FindingsUsing an elaborate index case tracing method, we attempted to locate all symptomatic VL patients in eight districts of Bihar. Interviews and medical-record-reviews were conducted with cases (or next-of-kin for the dead) meeting the eligibility criteria. The information collected during the interviews included socio-demographic characteristics, onset of disease symptoms, place of diagnosis, pre- and post-diagnosis treatment history, type and duration of drugs received. In total, we analyzed data on 4925 VL patients—59% were male and 68% were less than 30 years old. There were 158 (3.2%) deaths and the incidence rate of mortality was 3.2/100 person-years. In the adjusted Cox-proportional-hazards analysis, treatment at public facility [Adjusted Hazard Ratio (AHR) = 0.61; 95% CI = 0.43–0.86], shorter (≤30 days) diagnostic delay [AHR = 0.62, 95% CI = 0.43–0.92], and treatment completion [AHR = 0.03, 95% CI = 0.02–0.05] emerged as significant negative predictors of mortality.ConclusionMortality reduction efforts in Bihar should focus on improving access to early diagnosis, quality treatment and treatment-adherence measures, with special emphasis on marginalized communities.

背景 内脏利什曼病（Visceral leishmaniasis, VL）在印度比哈尔邦（Bihar）流行率极高，若未得到规范诊断与治疗，致死率居高不下。然而此前缺乏高效的报告机制，阻碍了对有症状内脏利什曼病患者的死亡负担及其前驱因素的估算。本研究旨在精准估算比哈尔邦有症状内脏利什曼病的病例规模与死亡率，并明确与该病死亡相关的流行病学及卫生基础设施层面的预测因素。

研究方法与主要结果 本研究采用精细的指示病例追踪法，尝试定位比哈尔邦8个县区内所有有症状的内脏利什曼病患者。对符合纳入标准的患者（或逝者的近亲属）开展访谈与病历回顾，收集的信息涵盖社会人口学特征、症状发作时间、诊断地点、诊断前后的治疗史以及所使用药物的种类与疗程。本研究最终纳入4925例内脏利什曼病患者的数据分析：其中59%为男性，68%的患者年龄不足30岁；共出现158例死亡（占比3.2%），死亡率为3.2/100人年。经校正的Cox比例风险回归分析显示，在公立医疗机构接受治疗[校正后风险比（Adjusted Hazard Ratio, AHR）=0.61；95%置信区间（95% CI）=0.43~0.86]、诊断延迟时间较短（≤30天，AHR=0.62，95% CI=0.43~0.92）以及完成全程治疗（AHR=0.03，95% CI=0.02~0.05）均为死亡率的显著负向预测因素。

结论 比哈尔邦的内脏利什曼病死亡率防控工作应聚焦于提升早期诊断可及性、优化治疗质量以及强化治疗依从性，并重点关注边缘化群体。