Prevalence and associated risk factors for noma in Nigerian children: a systematic review and meta-analysis

Objectives To determine the prevalence, case-fatality rate, and associated risk-factors of Noma in children in Nigeria. Methods Search was conducted in PubMed, Google Scholar, and Cochrane Library databases. Data were extraction using a double-blind approach. Discrepancies were resolved by a third reviewer. Heterogeneity was evaluated using I2 statistics. Random-effects model was used for the meta-analysis and subgroup analysis was conducted. The study quality was evaluated using standard Critical-Appraisal-Checklist. Results Of the 1652 articles identified, 12 studies that met the inclusion criteria included 871 cases of Noma. Two studies had high-risk of bias and were excluded in the meta-analysis. Pooled prevalence of Noma was 2.95% (95%CI:2.19-3.71; Z = 7.60; p < 0.00001, I2:100.0). Case fatality was reported in one study. Sex-distribution had a male-to-female ratio of 1.1:1. Malnutrition (88.42%, 95%CI:52.84-124.00; I2:100.0), measles (40.60%; 95% CI:31.56-49.65; I2:100.0) and malaria (30.75%; 95% CI:30.06-31.45; I2:100.0) were the most notable associated risk-factors. Prevalence of Noma was non-significantly lower in southern (1.96%,95%CI:1.49-2.44;6 studies) than in northern (4.43%; 95%CI:-0.98-9.83; 4 studies) Nigeria. One study reported the prevalence of Noma in children younger than 5 years. Conclusions About every 3 in 100 children in Nigeria had Noma and the prevalence was non-significantly higher in northern than southern Nigeria. Malnutrition, measles, and malaria were major associated risk-factors. Case-fatality rate and prevalence based on different age-groups were inconclusive.