Leprosy relapse after polychemotherapy: a systematic review and meta-analysis

Objective : To synthesize the best scientific evidence related to estimating the prevalence of leprosy relapse cases after polychemotherapy treatment. Method: A systematic review was conducted following the JBI methodology for systematic reviews of prevalence studies, and the reporting stage adhered to PRISMA-P, with registration No.: CRD42020177141. The inclusion criteria were adopted following the PopCoCo mnemonic (Population, Condition, Context). Population: people of both genders and any age, diagnosed with leprosy relapse, and treated with paucibacillary or multibacillary therapeutic regimes. Condition: leprosy relapse after Polychemotherapy (PCT) estimated as a proportion of cases. Context : studies conducted within the scope of health services. Databases used: Medline, LILACS, Embase, CINAHL, Scopus, WoS, CARPHA; Mendeley reference manager. A random-effects meta-analysis model was applied, and heterogeneity was assessed using the Higgins test. Results : Out of 41 studies included in the review, involving a total of 93,461 patients with leprosy, 4.09% (n=3,830) were eligible for relapse after polychemotherapy. Of them, 69.71% (n=2,670) were treated both with multibacillary and with paucibacillary regimes (72.36%, n=1,932; and 27.64%, n=738, respectively), and with a bacilloscopy index ≥4. Relapse prevalence was observed in males and in people aged over 30 years old. The meta-analysis estimated the global prevalence of leprosy relapse at 11% (95%CI: 0.09-0.12), with higher prevalence rates in Brazil (31%) and India (13%). Conclusion : There is evidence of high global prevalence of leprosy relapse after PCT, with higher estimates in India and Brazil, countries burdened with higher prevalence of the disease. SYNTHESIS Although leprosy us an ancient disease with a scientifically proven effective treatment, it remains a Public Health problem. This is not only due to the disease high prevalence but also to its potential to cause physical disabilities, leading to emotional and social impacts and, consequently, compromising quality of life. In addition to the new cases of the disease, another concern commonly reported in the literature is leprosy relapse after polychemotherapy, as it has repercussions on therapeutic effectiveness. The relapse causes are usually associated with therapeutic failure due to incomplete treatment, misclassification in the initial treatment, and multidrug resistance. This study provides insights to verify the disease current prevalence based on scientific evidence, which can contribute to expanding the prevention strategies. ### Competing Interest Statement The authors have declared no competing interest. ### Funding Statement Yes ### Author Declarations I confirm all relevant ethical guidelines have been followed, and any necessary IRB and/or ethics committee approvals have been obtained. Yes The details of the IRB/oversight body that provided approval or exemption for the research described are given below: N/A I confirm that all necessary patient/participant consent has been obtained and the appropriate institutional forms have been archived, and that any patient/participant/sample identifiers included were not known to anyone (e.g., hospital staff, patients or participants themselves) outside the research group so cannot be used to identify individuals. Yes I understand that all clinical trials and any other prospective interventional studies must be registered with an ICMJE-approved registry, such as ClinicalTrials.gov. I confirm that any such study reported in the manuscript has been registered and the trial registration ID is provided (note: if posting a prospective study registered retrospectively, please provide a statement in the trial ID field explaining why the study was not registered in advance). Yes I have followed all appropriate research reporting guidelines, such as any relevant EQUATOR Network research reporting checklist(s) and other pertinent material, if applicable. Yes All relevant data are in the manuscript and its supporting information files.