The presence of obesity paradox in Greek patients with chronic heart failure.

Abstract

Purpose: To investigate the effect of body mass index (BMI) values on 1- and 2-year mortality rates in patients with chronic heart failure (HF).

Patients and methods: We conducted a retrospective cohort study of 112 patients with confirmed HF who visited the HF outpatient unit of a tertiary hospital of Athens, Greece, during a 5-month period (December 2012 - April 2013). These patients were assigned to four groups based on their BMI category. Data collection was carried out through a review of the medical patient records and the filling in of a structured questionnaire, including information on the demographic and clinical patient variables. Additionally, 1- and 2-year patient mortality was recorded. The statistical significance was two-tailed, and p-values of less than 0.05 were considered significant. The statistical analysis was performed with Mann-Whitney U test, χ² test, and Student's t-test using the SPSS software (IBM SPSS 21.0 for Windows).

Results: Obese patients had significantly lower 1-year (13% vs 34.6%, p=0.039) and 2-year (4% vs 21.4%, p=0.022) mortality rates compared with those with normal BMI values. Additionally, we found clinically and not statistically significant lower mortality in overweight and obese patients, when compared with normal BMI and overweight patients, respectively.

Conclusion: Obesity paradox seems to be present in our study, translating to significantly lower long-term mortality rates of obese patients compared to those with normal BMI. The significantly higher left ventricular ejection fraction and hematocrit levels among obese HF patients could justify our study findings. Further research is needed due to the inherent weaknesses of BMI and the other study limitations.