Obesity versus underweight: the prognostic impact of body mass phenotypes in hospitalized older patients

Abstract

Objective: To compare the frequency of underweight and obesity among previously hospitalized older adults and analyze their association with malnutrition, sarcopenia, frailty, inflammatory markers, and adverse outcomes both during hospitalization and after discharge. Methods: This secondary analysis of a prospective study, conducted at Hospital das Clínicas da Universidade Federal de Pernambuco, Brazil, included hospitalized older patients (age ≥ 60 y). Nutritional status, body composition, sarcopenia, frailty, and outcomes were assessed. Cox regression was performed to evaluate the impact of the body mass phenotypes on clinical outcomes. Results: This secondary analysis included one hundred patients. The prevalence of obesity was 22.10%, while that of underweight was 34.60%. Individuals with underweight had a higher frequency of weaker immune response, worse inflammatory profile, higher nutritional risk, higher frequency of sarcopenia and malnutrition, longer hospital stay, and a higher incidence of mortality when compared to those with obesity. Being underweight was independently associated with higher mortality rates, even after adjustment for age, sex, muscle mass, malnutrition, and diagnosis of malignancy [adjusted HR = 2.82 (95% confidence interval 1.03 – 7.72), p = 0.044]. Conclusion: The underweight phenotype represented a worst-case scenario in hospitalized older patients.