Impact of Obesity and Underweight Status by Body Mass Index on Mortality Among Hospitalized Patients With Hypertrophic Cardiomyopathy

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Introduction: Even though obesity is associated with increased phenotypic expression in patients with hypertrophic cardiomyopathy (HCM), the effect of body mass index (BMI) on in-hospital mortality among hospitalized patients with HCM has not been established.

Hypothesis: We hypothesized that among hospitalized patients with HCM, obesity and underweight status are associated with increased mortality

Methods: We evaluated the National Inpatient Sample database to identify all adults (age ≥18 years) with HCM hospitalized for any cardiac illness between 2008 and 2017. Using ICD codes for BMI, the study cohort was stratified into underweight (BMI ≤19.9 kg/m2), non-obese (BMI 20.0-29.9 kg/m2), class I obesity (BMI 30.0-34.9 kg/m2), class II obesity (BMI 35.0-39.9 kg/m2) and class III (BMI ≥40.0 kg/m2). Multiple logistic regression analysis was used to analyze the independent association of various BMI categories and in-hospital mortality adjusted for age, sex and medical comorbidities.

Results: The survey-weighted sample included a total of 2,392,325 hospitalizations with a mean age of 66.1±12.2 years and 42.0% were females. The patients with class III obesity [adjusted mortality rate (AMR) 3.3%, adjusted odds ratio (AOR) 1.53, 95% confidence interval (CI)-1.29-1.82,p

Conclusions: Among patients with HCM, BMI has a non-linear U-shaped relationship with in-hospital mortality. The patients who were underweight and morbidly obese had significantly higher mortality, whereas those patients with class I and class II obesity had lower mortality compared to non-obese patients.