Flow chart of the selection process of the studies reviewed.

<p>Flow chart of the selection process of the studies reviewed.</p

Factors Associated with Visceral Leishmaniasis in the Americas: A Systematic Review and Meta-Analysis

<div><p>Background</p><p>Still today, more than 30 years after the beginning of the process of visceral leishmaniasis' urbanization, there is little knowledge about the risk factors for its occurrence, despite their relevance to the control and understanding of disease dynamics. The present study is the first systematic review with meta-analysis about factors associated with <i>Leishmania infantum</i> infection in humans in the Americas.</p><p>Methods and Findings</p><p>After searching different databases, consultations to the reference lists of articles and to experts in the field, 51 studies were reviewed. Theoretical discussions or meta-analysis of p-values or of effect sizes were used to pool information about each variable. The Q test and the I² statistic were used to assess heterogeneities among the studies. Male sex was associated with visceral leishmaniasis in studies which used the leishmanin skin test for diagnosis and in those where the outcome was the clinical disease; the opposite occurred when serological diagnosis was applied. Younger individuals were less frequently infected than adults, but were more prone to illness. Although with different levels of evidence and of heterogeneity, the presence of dogs at home, higher dog seropositivity in nearby areas, lower socioeconomic status and highly vegetated areas were associated with <i>L. infantum</i> infection. This was not noticed for the presence of chickens in the house and with nutritional status. Susceptibilities to bias and limitations in the analysis and in the description of results were often identified in the studies analyzed.</p><p>Conclusions</p><p>Results showed the existence of consistent patterns for some of the factors analyzed and should be taken into account in developing more effective and well-targeted control measures. Studies must be conducted in new areas of the continent, with improved methodological quality and prioritizing the investigation of the patterns identified and their causes, as well as variables for which knowledge is poor.</p></div

Flowchart showing the selection of studies analyzed in this review.

<p>Flowchart showing the selection of studies analyzed in this review.</p

Forest plot for the variable age: studies divided into subgroups according to the method for measuring the outcome.

<p>CS-Cross-sectional; *Serological result from study with two tests; #Result in adults; LST- Leishmania skin test; Squares represent the weight of each study; Lozenges represent the summary measure of each subgroup; Reference: Being Over 10 y.o.a., OR = 1.</p

Forest plot: malnutrition.

<p>CS-Cross-sectional; *Serological result from study with two tests; (2) According to a study from the same publication; LST-Leishmania skin test; Squares represent the weight of each study; Lozenges represent the summary measure. Reference: Lack of Malnutrition, OR = 1.</p

Forest plot for the variable gender: studies divided into subgroups according method for measuring the outcome.

<p>CS-Cross-sectional; *Serological result from study with two tests; #Result in adults; (2) Second study from the same publication; LST- Leishmania skin test; Squares represent the weight of each study; Lozenges represent the summary measure of each subgroup; Reference: Females, OR = 1.</p

Risk Factors for Adverse Prognosis and Death in American Visceral Leishmaniasis: A Meta-analysis

<div><p>Background</p><p>In the current context of high fatality rates associated with American visceral leishmaniasis (VL), the appropriate use of prognostic factors to identify patients at higher risk of unfavorable outcomes represents a potential tool for clinical practice. This systematic review brings together information reported in studies conducted in Latin America, on the potential predictors of adverse prognosis (continued evolution of the initial clinical conditions of the patient despite the implementation of treatment, independent of the occurrence of death) and death from VL. The limitations of the existing knowledge, the advances achieved and the approaches to be used in future research are presented.</p><p>Methods/Principal Findings</p><p>The full texts of 14 studies conforming to the inclusion criteria were analyzed and their methodological quality examined by means of a tool developed in the light of current research tools. Information regarding prognostic variables was synthesized using meta-analysis. Variables were grouped according to the strength of evidence considering summary measures, patterns and heterogeneity of effect-sizes, and the results of multivariate analyses. The strongest predictors identified in this review were jaundice, thrombocytopenia, hemorrhage, HIV coinfection, diarrhea, age <5 and age >40–50 years, severe neutropenia, dyspnoea and bacterial infections. Edema and low hemoglobin concentration were also associated with unfavorable outcomes. The main limitation identified was the absence of validation procedures for the few prognostic models developed so far.</p><p>Conclusions/Significance</p><p>Integration of the results from different investigations conducted over the last 10 years enabled the identification of consistent prognostic variables that could be useful in recognizing and handling VL patients at higher risk of unfavorable outcomes. The development of externally validated prognostic models must be prioritized in future investigations.</p></div

Forest plot for the presence of chickens, birds or chicken coops in the household.

<p>CS-Cross-sectional; *Serological result from study with two tests; (2) According to a study from the same publication; LST-Leishmania skin test; Squares represent the weight of each study; Lozenges represent the summary measure; Reference: Not Owning Birds, OR = 1.</p

Index terms used in the search of published data.

<p>CAPES databank is a collection of theses and dissertations published by Brazilian academic institutions and assembled by Coordenação de Aperfeiçoamento de Pessoal de Nível Superior.</p

Funnel plot for the variables employed in the detection of publications bias in the review.

<p>a-gender; b-age; c-presence of dogs in the household; d-presence of chickens or birds in the household; Dots refer to studies imputed by the Trim and Fill method. Open diamonds represent the original estimate of the Odds ratios while solid diamonds represent Odds rations recomputed by the statistic of Durval and Tweedie's Trim and Fill.</p