Avaliação do desempenho de métodos diagnósticos de anemia e deficiência de vitamina A em crianças menores de cinco anos

• Autor(a) principal: Pereira, Alessandra da Silva
• Data de Publicação: 2018
• Tipo de documento: Tese
• Idioma: por
• Título da fonte: Biblioteca Digital de Teses e Dissertações da UERJ
• Texto Completo: http://www.bdtd.uerj.br/handle/1/7193
• topic: Anemia; VAD; Portable hemoglobinometer; Dry drop blood; Reproducibility; DVA; Gota seca; Reprodutibilidade; Validade; Nutrição; Anemia; Hemoglobinômetro portátil; CNPQ::CIENCIAS DA SAUDE::NUTRICAO::ANALISE NUTRICIONAL DE POPULACAO

Introduction: Anemia and vitamin A deficiency (DVA) are diseases that have a high global prevalence. Methods frequently used in epidemiological studies on these diseases were not sufficiently evaluated. Objective: Evaluate the performance of two diagnostic methods of anemia (portable hemoglobinometer and dry blood spots) and a diagnostic method of DVA (dry blood spots) in children under five years old. Methods: Venous and capillary blood samples were collected from children of SUS in Rio de Janeiro. The hemoglobin reference method was the venous blood automated system analysis and two methods were tested - portable hemoglobinometer and dry blood spots, both with capillary blood samples. For retinol, the reference method was serum retinol analysis by High Performance Liquid Chromatography (HPLC) with venous blood and the test was a dry blood spots of capillary blood also analyzed by HPLC. The reliability study was performed by analyzing the reproducibility of the hemoglobin and retinol concentration of the test methods. Concordance analyzes of continuous variables were performed using the intraclass correlation coefficient (ICC) and categorical variables (presence or absence of the disease), using the Kappa and Kappa indices adjusted for the interviewer's prevalence and bias (PABAK). Validity analysis consisted of the determination of sensitivity, specificity, accuracy, positive and negative predictive value of the test methods compared to reference methods in the diagnosis of VAD and anemia. Results: 351 children participated in the analysis of the performance of the portable hemoglobinometer. In the analysis of dry drop blood spots, 235 children were studied for retinol and 182 for hemoglobin. Statistically significant differences were observed only between the hemoglobin averages obtained by the portable hemoglobinometer (12,04±1,11 g / dl) and the automated system (11.86 ± 0.97 g / dl, p <0.005). The hemoglobinometer showed good reproducibility of the device (ICC = 0.79) and method reproducibility (puncture, collection and reading) (ICC = 0.71), reasonable (kappa) and good agreement (PABAK) among the diagnoses obtained by the method test. The prevalence of anemia, 19.1% obtained by the reference method (19.1%) and the test method (19.7%) did not present statistically significant differences. The test method presented greater specificity (87.7%) and NPV (88.3%) than sensitivity (50.7%) and PPV (49.3%), and intermediate accuracy index (57.8%). The dry blood spots presented very good reliability for retinol (ICC = 0.94, kappa = 0.83, PABAK = 0.76) and reasonable for hemoglobin (ICC = 0.86, kappa = 0.69, PABAK = 0.69). The prevalence obtained by reference and test methods were 11.5% and 11.9%, respectively, for VAD and 19.2% and 46.2%, respectively, for anemia, presenting statistically significant differences, in second case (p <0.005). The test method presented low sensitivity (33%) and PPV (32%) and high specificity (91%) and NPV (92%) for DVA. Reasonable sensitivity (71%), low PPV (30%), reasonable specificity (60%) and high NPV (90%) were observed for hemoglobin. The accuracy rates were 83% for VAD and 62% for anemia. Conclusion: In the epidemiological context studied, the portable hemoglobinometer was more adequate to estimate the prevalence of anemia in children than for the individual diagnosis. The dry blood spots presented good reliability for both retinol and hemoglobin, however, a reasonable validity for the diagnosis of VAD and low for anemia