Impact of Obesity in Hospitalized Patients with Heart Failure: A Nationwide Cohort Study

Abstract

Objectives: Obesity and cardiovascular disease remain significant burdens on the overall provision of health care in the United States. Obesity has been shown to be a direct risk factor for heart failure (HF). We conducted a nationwide cohort study to assess the short-term impact of obesity in hospitalized patients with HF.

Methods: We identified 1,520,871 encounters with a primary diagnosis of HF in the 2013-2014 Nationwide Readmission Database. We excluded patients younger than 18 years (n = 2755), hospitalized patients discharged in December (n = 126,137), patients with missing mortality information (n = 477), missing length of stay (LOS; n = 91), patients who were transferred to another hospital (n = 38,489), and patients with conflicting body weight information (n = 7757). Multivariable logistic regression was used to evaluate the association between baseline characteristics (including the presence of obesity) and in-hospital mortality, as well as 30-day readmission rates.

Results: The overall in-patient mortality rate was 2.8% (n = 37,927). Obese patients had numerically a lower mortality (1.8%) compared with the nonobese patients (3.1%); however, the difference in risk was not significant on multivariable analysis (hazard ratio 0.97, 95% confidence interval 0.94-1.01). In the overall cohort, 20.6% (n = 269,988) were readmitted within 30 days. The risk of 30-day readmission was significantly lower in obese patients (19.4%) compared with nonobese patients (20.9%) (odds ratio 0.85, 95% confidence interval 0.84-0.86). Obese patients had longer LOSs (median of 5 days [3-7] vs 4 days [2-6], P < 0.001) and higher costs of index admission (median of $27,206 [$16,027-$48,316] vs $23,339 [$13,698-$41,982], P < 0.001) compared with nonobese patients.

Conclusions: In this cross-sectional study of patients hospitalized for HF in the United States, obesity was not associated with a higher risk of inpatient mortality, but it was associated with a lower 30-day readmission rate. Obese patients with HF, however, had longer LOSs and higher costs of index admission. Our findings support the obesity paradox seen in patients with HF.