ABC | Volume 113, Nº6, December 2019

Original Article Leite et al. Risk of sleep apnea and echocardiographic parameters Arq Bras Cardiol. 2019; 113(6):1084-1089 Methods A cross-sectional study that integrates the DIGITALIS STUDY and included 633 individuals (51% females) between 45 to 99 years of age enrolled in the PMF, Niterói, RJ. The data were obtained from July 2011 to December 2012. The methodology applied was previously described. 8 All individuals selected for the study were evaluated on a single day. The evaluation included the following procedures: filling out the questionnaire, consultation and clinical examination, laboratory tests and transthoracic Doppler echocardiography (TDE). Of the 633 participants examined by the DIGITALIS STUDY, 64 were excluded for having been diagnosed with HF or for not having answered the BQ completely, and 214 for having hypertension or being obese and not having been classified as having risk of OSA by other criteria. For the present analysis, 354 individuals were included (figure 1). The TDE scans were performed by two echocardiographers who had no previous knowledge of the results of the other tests, using two pieces of equipment (Cypress 20 Acuson/ Siemens EUA/AU-3 Partner, Esaote — Italy). The tests were performed according to the recommendations for quantification of chambers of the American Society of Echocardiography (ASE) and the European Association of Echocardiography (EAE). Systolic function was evaluated by measuring the left ventricular ejection fraction (LVEF) by the Simpson’s method. 9 The participants were categorized into positive or negative for the risk of OSA based on their answers to the individual items of the QB and their total score in the categories of symptoms. 5 Statistical analysis This was performed with the SPSS v 21.0 (Chicago, Illinois, USA). Continuous data are presented as medians and interquartile ranges and categorical variables as relative and absolute frequencies. The differences between groups with and without risk of OSA were tested by the non-parametric Mann-Whitney test and the categorical variables by the qui-square test with correction of continuity and Fisher’s exact test, when necessary. The variables that presented an association with the risk of OSA at a 0.05 level integrated the gamma regression models with a log link function. As echocardiographic parameters are very correlated among each other, it was chosen to adjust a model for each parameter (outcome) associated with the presence or absence of risk of OSA in the preliminary analysis at a level of 0.05. Exposed and non-exposed coefficient exponentials are interpreted as the result of the arithmetic means of the outcome. A value of p < 0.05 was considered an indicator of statistical significance. Ethical considerations This study was conducted according to the principles established in the Declaration of Helsinki, revised in 2000 (Scotland, 2000). The protocol for the study was approved by the Institution’s Research Ethics Committee under code number CAAE :0077.0.258.000-10 . Results Of the 354 individuals analyzed, 63% were classified as having a risk of OSA. Table 1 presents the clinical characteristics according to the presence of the risk of OSA. Individuals with risk were mostly women, older, with higher BMI, glucose, uric acid and triglyceride levels, urine albumin-to-creatinine ratio and blood pressure. The patients with risk of OSA, compared to the ones with no risk, presented greater abnormalities of the diastolic function parameters: LAV-i (+), DT (+), E(-), E’/A’ (+), E/E’ (-), A(+), E/A (+), PPEI (+) and VIS (+), which may indicate a less effective diastolic function. Such differences were statistically significant (Table 2). Figure 1 – Flowchart of sample selection. BQ: Berlin Questionnaire; HF: heart failure; HBP: high blood pressure or arterial hypertension; OSA. 633 Patients that completed the cardiac investigation of the study Digitalis Phase 1 64 Excluded for HF 1 Failed to fill out BQ 354 Individuals included in the study 214 Excluded for presenting SAH and/or obesity as the only criterion for OSA 1085