Cox ZL, et al. – The proposition under exploration here was that increasing obesity would increase the rate of 30–day all cause hospital readmissions, after an index heart failure (HF) hospitalization compared to a normal body–mass index (BMI). The data disclosed that elevated BMI increased the rate of hospitalization after a HF admission compared to a normal BMI, with the exception of morbidly obese individuals. This finding appeared to be in contrast to the paradoxical effects on mortality.

Methods

• The enrollment included patients (n = 1,454) aged ≥ 65 years with Centers of Medicare Services (CMS) benefits and a primary discharge diagnosis of HF from an academic medical center.
• The candidates were included in the CMS Hospital Readmission Reduction Program report from 2009 - 2014.
• Obesity was classified by BMI based on the World Health Organization: Underweight (BMI <18.5 kg/m²), Normal (18.5-24.9 kg/m²), Overweight (25.0-29.9 kg/m²), Class I Obesity (30.0-34.9 kg/m²), Class II Obesity (35.0-39.9 kg/m²), and Morbid Obesity (≥40.0 kg/m² ).
• The primary outcome was 30-day all-cause readmission to any hospital after a HF admission.
• The CMS Inpatient Quality Report on HF 30-day mortality examined the mortality incidence.
• Classification was performed of the readmission reasons by primary discharge diagnosis using Clinical Classification Software from the AHRQ.

Results

• The cohort BMI distribution included 2.9% Underweight, 29.1% Normal, 30.3% Overweight, 19.7% Class I Obesity, 9.5% Class II Obesity, and 8.5% Morbid Obesity.
• Compared to Normal BMIs, those in elevated BMI groups were younger (P < .001) and reported a higher prevalence of diabetes (P < .0001) and obstructive sleep apnea (P < .0001).
• The 30-day all cause readmission rate appeared to be 21.3 % (n = 309) and 30-day mortality rate was 7.1% (n = 103).
• The readmissions were found to be more frequent among the Overweight (22.4%; P = .04), Class I Obesity (26.8%, P = .001), Class II Obesity (24.6%, P = .04), but not Morbid Obesity (18.7%, P = .6), than the the 30-day all cause readmission rate in the Normal BMI group (16.8%).
• Lower mortality rates were found among the Overweight (6.1%; P = .04), Class I Obesity (5.2%, P = .02), Class II Obesity (3.6%, P = .02), but not Morbid Obesity (6.5%, P = .2) compared to the Normal BMI group (9.9%).
• Among the 309 readmissions, the most frequent reasons were HF (n = 107; 35%), infection (n = 32; 10%), and AKI (n = 25; 9%).
• Similar percentage of readmissions from non-HF diagnoses were reported across BMI groups: Normal (66%), Overweight (63%), Class I Obesity (62%), Class II Obesity (68%), except Morbid Obesity (83%).