O tratamento para a esquistossomose e seu efeito nas morbidades: revisão sistemática e metanálise

Abstract

Schistosomiasis is an important public health problem in tropical and subtropical regions. In endemic areas, the chronic state of the infection generates an impact on the health of the individuals due to the disease. Since the 1980s, WHO has chosen chemotherapy as the most appropriate method to control the morbidities associated with infection with Schistosoma species. Thus, extensive use of the drug requires a comprehensive understanding of its impact on the control of related morbidities. The objective of this study was to evaluate the impact of drug treatment on the morbidities and symptoms associated with Schistosoma species infection through a systematic review and meta-analysis. The review project was registered on the PROSPERO (CRD42015026080). Studies were identified through a systematic search using PubMed and BVS/BIREME. Studies that evaluated Schistosoma infection before and after specific chemotherapy for schistosomiasis were included in this review. election was performed by two independent researchers and included the following criteria: prospective longitudinal studies, without date restriction, published in English, Portuguese, Spanish or French, which were not performed in hospitals and did not perform concomitant treatment of the subjects. From each study data were extracted on the characteristics of the study, the participants, the intervention performed, the outcomes evaluated and the follow-up time. The data were analyzed in Comprehensive Meta-Analysis® software. The random effect model was used to derive the meta-analytic estimates. For the morbidities referred dichotomous outcomes, the pooled odds ratio was calculated and for the continuous data, the effect measure was calculated by the standardized mean difference, all with a 95% confidence interval. In addition, meta-regression was performed to correlate the reduction in egg count and post-treatment odds ratios or standardized mean differences of each outcome. The heterogeneity was evaluated by the chi-square test and the I2 statistic. To explore the heterogeneity and potential factors that could modify the measure of effect, subgroup analyzes were performed. We selected 71 studies in 64 publications. The studies involved a total of 24.214 individuals. Most of them have been performed with school-age children (45%), with S. haematobium (52%), treatment with praziquantel (81.7%) and conducted in Africa (83%). Most of the evaluated morbidities presented a reduction compared to pre-treatment levels: left hepatic lobe enlarged reduced by 54% (OR 0.46, CI95% 0.32-0.67); right hepatic lobe enlarged by 47% (OR 0.53, CI95% 0.32-0.84); splenomegaly in 37% (OR 0.63, CI95% 0.47-0.84); periportal fibrosis in 52% (OR 0.48, IC95% 0.34-0.68); diarrhea in 53% (OR 0.47, CI95% 0.29-0.78); blood in the stool by 75% (OR 0.25, CI95% 0.15- 0.42); hematuria in 92% (OR 0.08, CI95% 0.05-0.11); proteinuria by 90% (OR 0.10, CI95% 0.05-0.19); abnormalities in the urinary bladder in 86% (OR 0.14, CI95% 0.09-0.20); lesions in the upper urinary tract in 72% (OR 0.28, CI95% 0.16-0.51). Significant reduction was not found for dilated portal vein (OR 0.57, CI95% 0.23-1.42) and hemoglobin levels (0.60 g / dL; CI95% -0,2/1,42). In the subgroup analysis, the results were influenced by the age of the subjects, Schistosoma species, study site, time of follow-up, and prevalence of infection. In addition, it was observed that higher rate of egg reduction correlated with greater reduction in the probabilities of most morbidities. Although there are challenges to implementing therapy for schistosomiasis, reductions in egg production are significantly correlated with decreased morbidity and can be used to project the reduction of disease burden in more aggressive strategies to minimize the intensity of infection.