Intracluster correlation coefficients for the Brazilian Multicenter Study on Preterm Birth (EMIP): methodological and practical implications

Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq)Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)Background: Cluster-based studies in health research are increasing. An important characteristic of such studies is the presence of intracluster correlation, typically quantified by the intracluster correlation coefficient (ICC), that indicate the proportion of data variability that is explained by the way of clustering. The purpose of this manuscript was to evaluate ICC of variables studied in the Brazilian Multicenter Study on Preterm Birth. Methods: This was a multicenter cross-sectional study on preterm births involving 20 referral hospitals in different regions of Brazil plus a nested case-control study to assess associated factors with spontaneous preterm births. Estimated prevalence rates or means, ICC with 95% confidence intervals, design effects and mean cluster sizes were presented for more than 250 maternal and newborn variables. Results: Overall, 5296 cases were included in the study (4,150 preterm births and 1,146 term births). ICC ranged from 0.3 was found in some clinical management aspects well defined in literature such as use of corticosteroids, indicating there was homogeneity in clusters for these variables. Conclusions: Clusters selected for Brazilian Multicenter Study on Preterm Birth had mainly heterogeneous findings and these results can help researchers estimate the required sample size for future studies on maternal and perinatal health.14Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq)Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq)Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)FAPESP [2009/53245-5, 2014/08183-0

Intracluster correlation coefficients for the Brazilian Multicenter Study on Preterm Birth (EMIP): methodological and practical implications

Cluster-based studies in health research are increasing. An important characteristic of such studies is the presence of intracluster correlation, typically quantified by the intracluster correlation coefficient (ICC), that indicate the proportion of data variability that is explained by the way of clustering. The purpose of this manuscript was to evaluate ICC of variables studied in the Brazilian Multicenter Study on Preterm Birth. This was a multicenter cross-sectional study on preterm births involving 20 referral hospitals in different regions of Brazil plus a nested case-control study to assess associated factors with spontaneous preterm births. Estimated prevalence rates or means, ICC with 95% confidence intervals, design effects and mean cluster sizes were presented for more than 250 maternal and newborn variables. Overall, 5296 cases were included in the study (4,150 preterm births and 1,146 term births). ICC ranged from 0.3 was found in some clinical management aspects well defined in literature such as use of corticosteroids, indicating there was homogeneity in clusters for these variables. Clusters selected for Brazilian Multicenter Study on Preterm Birth had mainly heterogeneous findings and these results can help researchers estimate the required sample size for future studies on maternal and perinatal health14CONSELHO NACIONAL DE DESENVOLVIMENTO CIENTÍFICO E TECNOLÓGICO - CNPQFUNDAÇÃO DE AMPARO À PESQUISA DO ESTADO DE SÃO PAULO - FAPESPsem informação2009/53245-5; 2014/08183-

Mortality of diabetic on chronic dialysis in Tunisia

Survival rates of diabetic patients on maintenance hemodialysis (HD) are reported to be poorer in Tunisia than in developed countries. This study aims to specify the epidemio-logical, clinical, and biological characteristics of diabetic disease, chronic kidney disease (CKD), and comorbidities at the initiation of HD and investigate factors associated with mortality during the dialysis period. We retrospectively analyzed the outcome of diabetic patients who were initiated on HD from 2007 to 2012 at the Rabta Hospital of Tunis. During the follow-up period, all morbid events and deaths were recorded. Univariate analysis and multivariate analysis were performed to identify risk factors associated with mortality in our population. The study population included 142 patients. The mean age was 58.7 ± 11.9 years. The sex ratio male/female was 1.4. One hundred and twenty-seven patients were type 2 diabetics (89.4%). Diabetic nephropathy was the main initial nephropathy (87.3%). CKD was diagnosed at Stages 4 or 5 in 95.1% of cases. HD was started in emergency conditions in 68.6% of cases. The one-year and the five-year survival rates were 42% and 17%, respectively. At initiation of HD, low socioeconomic status (P = 0.001), advanced age (P = 0.008), low body mass index (P = 0.04), history of stroke (P = 0.04), peripheral neuropathy (P = 0.02), initial vascular access (P = 0.03), secondary hyperpara-thyroidism (P = 0.03), nephrotic-range proteinuria (P = 0.01), and glycated hemoglobin ≤7% (P = 0.03) were associated with higher mortality rate. During dialysis period, cardiovascular events (P = 0.02), infectious complications (P = 0.04), and secondary hyperparathyroidism (P = 0.04) were significantly more noticeable among deceased patients. Due to poor survival rates of diabetic patients on HD, prevention, early detection, and management of diabetic CKD patients should be the way to go forward