Leprosy relapse after multidrug therapy: Systematic review and meta-analysis

Objective: To synthesize the scientific evidence regarding the prevalence of leprosy relapse following multidrug therapy. Method: A systematic review was conducted following the JBI methodology for prevalence studies and reported according to the guidelines, with the registration number CRD42020177141. The inclusion criteria were based on the mnemonics (Population, Condition, Context). Population: Individuals of any age or sex diagnosed with leprosy relapse and previously treated with paucibacillary or multibacillary multidrug therapy. Conditions: Leprosy relapse after multidrug therapy, measured as the proportion of cases. Context: Studies conducted within the healthcare service settings. The databases searched included Medline, Latin American and Caribbean Health Sciences Literature (LILACS), Embase, Cumulative Index to Nursing and Allied Health Literature (CINAHL), Scopus, WoS, and Caribbean Public Health Agency (CARPHA). The references were managed using Mendeley. A random-effects meta-analysis model was employed, and heterogeneity was assessed using Higgins’ I² statistics. Results: Of 26 studies (a combined sample of 71,385 participants), 19 were included in the meta-analysis. A higher prevalence of relapse was observed in working-age males, multibacillary cases with a high bacillary load, and those with established physical disabilities. The estimated prevalence of relapse across studies ranged from 0% to 10%, with a pooled estimate of 4% in India (95% CI: 0.03–0.05). The overall point estimate for relapse using regular multidrug therapy was 0.04 (95% CI: 0.02–0.05). Conclusion: The prevalence of relapse varied according to the geographic location and type of multidrug therapy, with substantial heterogeneity across studies. These findings suggest that factors such as individual patient characteristics, treatment adherence, and capacity for healthcare services may have influenced the outcomes observed in this review. Author summary: Leprosy is considered a millennial and neglected disease. Despite the treatment with multidrug therapy (MDT) adopted by the World Health Organization (WHO) having reduced the number of new cases of the disease, it remains a public health problem. The physical disabilities associated with late diagnosis, stigma, discrimination, social restrictions, and consequently the loss of quality of life can increase the disease’s prevalence. Another important issue that negatively impacts disease control is the occurrence of relapse after MDT, which can compromise therapeutic efficacy. The causes of relapse are commonly associated with therapeutic failure due to incomplete treatment, errors in operational classification, and the existence of resistant bacteria. This study aims to synthesize the evidence on the prevalence of relapse after the adoption of MDT, which could contributed to the implementation of more assertive strategies to prevent the disease.