Measuring endemicity and burden of leprosy across countries and regions: A systematic review and Delphi survey

Abstract

Background Leprosy is a chronic infectious disease caused by Mycobacterium leprae, the annual new case detection in 2019 was 202,189 globally. Measuring endemicity levels and burden in leprosy lacks a uniform approach. As a result, the assessment of leprosy endemicity or burden are not comparable over time and across countries and regions. This can make program planning and evaluation difficult. This study aims to identify relevant metrics and methods for measuring and classifying leprosy endemicity and burden at (sub)national level. Methods We used a mixed-method approach combining findings from a systematic literature review and a Delphi survey. The literature search was conducted in seven databases, searching for endemicity, burden and leprosy. We reviewed the available evidence on the usage of indicators, classification levels, and scoring methods to measure and classify endemicity and burden. A two round Delphi survey was conducted to ask experts to rank and weigh indicators, classification levels, and scoring methods. Results The literature review showed variation of indicators, levels, and cut-off values to measure leprosy endemicity and/or burden. The most used indicators for endemicity include new case detection rate (NCDR), new cases among children and new cases with grade 2 disability. For burden these include NCDR, MB cases, and prevalence. The classification levels ‘high’ and ‘low’ were most important. It was considered most relevant to use separate scoring methods for endemicity and burden. The scores would be derived by use of multiple indicators. Conclusion There is great variation in the existing method for measuring endemicity and burden across countries and regions. Our findings contribute to establishing a standardized uniform approach to measure and classify leprosy endemicity and burden at (sub)national level, which would allow effective communication and planning of intervention strategies.

Experiences of living with leprosy: A systematic review and qualitative evidence synthesis

“…[ 7 ] There is significant variation in the distribution of leprosy globally, and within some countries with low prevalence, there are local pockets of high endemicity. [ 8 ] The global prevalence of leprosy at the end of 2020 was 129,192, with a corresponding prevalence rate of 16.6 per million population. [ 9 ] There were 127,396 new cases detected worldwide, with a new case detection rate of 16.4 per million population, and these figures were much lower than in previous years, probably due to reduced leprosy prevention activities caused by the COVID-19 pandemic resulting in less detection and reporting of cases.…”

Epidemiological characteristics of leprosy during the period 2005–2020: A retrospective study based on the Chinese surveillance system

“…NCDR, delayed diagnosis, adolescent cases, and G2D rate are the most critical indicators to evaluate the effectiveness of leprosy prevention and control ( 48 ). These indicators provide information about other factors that indirectly influence case detection, such as medical personnel's ability to recognize early symptoms.…”

The leprosy case detection delay (CDD) questionnaire: Indonesian translation, cross-cultural adaptation, and evaluation

“…14 These numbers indicate that leprosy and G2D due to leprosy still constitute a substantial public health burden in Indonesia. 15,16 A quantitative study on case detection delay in Indonesia, implemented the Rapid Village Survey (RVS). 17 This active case-finding method found 10% G2D in new leprosy cases.…”