Body Mass Index Affects Hospital-Associated Disability and Economic Burden in Elective Cardiovascular Surgery　― JROAD/JROAD-DPC Database ―

Abstract

Background: Both underweight and overweight are recognized as important factors influencing outcomes in patients undergoing cardiovascular surgery. This study investigated the effects of body mass index (BMI) on hospital-associated disability (HAD) and hospitalization costs in patients undergoing elective cardiovascular surgery (coronary artery bypass grafting, valve surgery, aortic surgery) by analyzing data from the Japanese Registry of All Cardiac and Vascular Diseases – Diagnosis Procedure Combination (JROAD-DPC) database.

Methods and Results: All patients in the JROAD-DPC database were categorized into 5 groups according to the World Health Organization BMI criteria for Asians. HAD was defined as a decrease of ≥5 points in the Barthel Index from admission to discharge. The primary outcome was the prevalence of HAD, and the secondary outcome was hospitalization costs. Among the 228,891 patients included in the study, the median BMI was 23.2 kg/m². The prevalence of HAD was 8.7%, with a U-shaped relationship between BMI and HAD, indicating that both extremely low and high BMIs were associated with a higher incidence of HAD. Hospitalization costs also showed a U-shape relationship with BMI, with higher costs for patients with HAD.

Conclusions: Low BMI in any age group was associated with HAD, and older people with a BMI considered too high also had HAD. BMI could be an important risk stratification tool for functional outcomes and economic burden in patients undergoing elective cardiovascular surgery.