Pakistan on the Road to Zero Leprosy, an analysis of routine data for the period 1980-2022: a retrospective cohort...

Leprosy prevalence in Pakistan has declined since multidrug therapy was introduced in the 1980s. In 1996, prevalence dropped below one per 10 000, the target set for elimination of leprosy as a public health problem. We explored trends in incidence, prevalence, and patient characteristics at national and subnational levels using routine data.

In this retrospective cohort study, we compiled leprosy incidence and prevalence rates from the database collected by the Pakistani National Leprosy Control Programme between Jan 1, 1980, and Dec 31, 2022 at the national level, with subnational-level analyses from Jan 1, 2001, to Dec 31, 2022. At the provincial level we explored trends in age distribution and disability grading of incident cases. At the subdistrict level we compiled the new WHO Leprosy Elimination Monitoring Tool (LEMT) over four periods and we conducted a spatial scan statistic (SaTScan) analysis to identify current high-incidence clusters.

We found 40 859 episodes of leprosy, with 30 522 from the 1980-2000 period and 10 337 from the 2001-22 period. Incidence and prevalence of leprosy have decreased significantly, with incidence decreasing from 23·5 per 1 million in 1980 to 1·1 per 1 million in 2022 and prevalence from 167·4 to 0·9 per 1 million. Trends are driven by the two largest provinces, Sindh and Punjab. Since 2001, the decline in incidence has been mainly driven by Sindh, whereas incidence in Punjab has remained stagnant. Nationally, the proportion of children among new cases has not significantly decreased (odds ratio per year 0·996 [95% CI 0·985-1·008]), suggesting ongoing transmission. The mean annual proportion of new patients with grade 2 disabilities also remains high (20·7%, SD 3·1). The LEMT and SaTScan analyses identified largely overlapping areas of ongoing transmission.

Although leprosy incidence has decreased, some high-incidence areas persist, requiring intensified interventions. Stable proportions of child cases also indicate ongoing transmission. In addition to LEMT, new tools such as geospatial mapping and phylogenetic analysis might help to better target elimination efforts.

Marie Adelaide Leprosy Center.