Influência do grau de obesidade ou da atividade física na variabilidade da frequência cardíaca ambulatorial e risco cardiovascular em pacientes obesos candidatos a cirurgia bariátrica

Abstract

This study evaluated whether the degree of obesity or physical activity influences blood pressure (BP) and ambulatory cardiac autonomic modulation in participants with obesity who intended to undergo bariatric surgery. It is a retrospective study of patients referred for preoperative cardiology evaluation for bariatric surgery, carried out at Clínica Cardios Exame Gráficos LTDA, from January 2010 to December 2018. Methods: Individuals with obesity (n = 1055) were divided into grade II obesity (n = 524) and grade III obesity (n = 531) groups (37.90 vs 42.3 kg/m2 ), and further divided into insufficiently active (n = 825) and physically active (n = 230) groups. Inclusion criteria were: age between 18 and 64 years; both sexes and BMI ≥ 35 kg/m2 . The following data were obtained from medical records: biographical (age, sex), anthropometric (body mass, height), personal history of cardiovascular risk factors (hypertension, diabetes mellitus, dyslipidemia, and smoking), use of medications, information regarding physical activity, vital signs at rest (heart rate - HR, blood pressure), and 24-hour cardiac autonomic modulation (Holter24-hour). Heart rate variability indices were analyzed in the time domain (SDNN, SDANN, rMSSD and pNN50) and in the frequency domain (LF, HF and LF/HF). The unpaired T-test for parametric data and the Mann-Whitney U test for nonparametric data were used to compare variables between 1) grade III vs. grade II obese group; 2) active vs. insufficiently active group; 3) low vs. high SDNN group. Categorical variables (gender, presence of grade III obesity, hypertension, diabetes mellitus, dyslipidemia, use of medications, and smoking) were compared using the Chi-square test. In addition, the odds ratio of the grade III obese group, the group with low SDNN, or the physically active group with a diagnosis of grade III obesity, arterial hypertension, diabetes mellitus, and dyslipidemia was calculated. Results: higher BP (128 vs 126 and 85 vs 84 mmHg, p < 0.01), odds of diagnosis of hypertension (OR 2.05 (1.60-2.63; p < 0.01) and use of hypertension medications (OR 2.00 (1.54-2.60; p < 0.01) and lower heart rate variability (HRV) indices (p < 0.01) were observed in the grade III obesity group compared to grade II. Obese individuals with low SDNN have higher indicators of obesity (41.30 vs 38.90 kg/m2; p < 0.01), BP (128 vs 126 and 85 vs 84 mmHg; p <0.05) and lower HRV indices (p < 0.01) compared to obese individuals with high SDNN, are also 74% more likely to be diagnosed with hypertension (OR 1.74 (1.36-2.22 p < 0.01), 88% more chance (OR 1.88 (1.45-2.44 p < 0.01) to take medication for hypertension, 11% more chance (OR 1.11-2.22 p < 0.01) to be diagnosed with DM, and grade III obesity individuals are 3.96 times more chance (OR 3.96 (3.07-5.11; p < 0.01) of presenting low SDNN. On the other hand, lower obesity indicators (39.80 vs 40.00 kg/m2; p < 0.01), systolic BP (125 vs 128 mmHg; p < 0.01), diagnosis of hypertension (OR 0.64 (0.47-0.87; p < 0.01) and use of hypertension medications (OR 0.70 (0.50-0.96; p = 0.02) and higher outpatient HRV indices were observed in the physically active group (p < 0.01) compared to the insufficiently active group. Conclusion: In summary, although grade III obesity showed a negative influence on outpatient BP and HRV, physical activity improved cardiac autonomic modulation and decreased the chance of hypertension and the use of medications.