Protein-energy undernutrition and the risk of mortality within six years of hospital discharge

Abstract

Objective: The primary objective was to determine whether protein-energy undernutrition among elderly patients discharged from the hospital remains a significant risk factor for mortality beyond 1 year.

Design: Prospective Survey (cohort study).

Setting: Outpatient follow-up of patients discharged from a Geriatric Rehabilitation Unit (GRU) of a Veterans Administration hospital.

Participants: Of 350 randomly selected admissions to the GRU, 322 were discharged alive from the hospital. These 322 patients represented the study population of whom 99% were male, and 75% were white. The average age of the study patients was 76 (range 58 to 102) years.

Measurements: At admission and again at discharge, each patient completed a comprehensive medical, functional, neuro-psychological, socioeconomic, and nutritional assessment. Subsequent to discharge, each subject was tracked for an average of 6 years. In addition to including serum albumin and other putative nutrition indicators in the data set, a "nutrition-risk" indicator variable was created. Subjects were stratified into the nutrition "high-risk" group if their albumin was less than 30 g/L or BMI was less than 19; and, "low-risk" group if albumin was equal to or greater than 35 g/L and BMI equal to or greater than 22. All others represented the "moderate-risk" group.

Results: Within the 6-year post-hospital-discharge follow-up period, 237 study subjects (74%) died. Based on the Cox proportional hazards survival model, the variable most strongly associated with mortality was discharge "nutrition-risk" followed by the Katz Index of ADL Score, diagnosis of congestive heart failure, discharge location (home vs. institution), age, and marital status. Within the first 4.5 years of follow-up, the relationship between "nutrition-risk" and mortality remained constant. After 4.5 years, the strength of the correlation began to diminish.

Conclusions: Among the elderly, protein-energy undernutrition present at hospital discharge appears to be a strong independent risk factor for mortality during the subsequent 4.5 years or longer.