54

Abstract

Introduction: Hospital readmission within 30 days of discharge occurs in 18% of Medicare beneficiaries and results in an annual cost of $15 billion. Little is known regarding risk factors associated with hospital readmission in critical illness survivors. Whether malnutrition at critical care initiation has prognostic implications for ICU survivors has not been studied. Methods: We performed a single center observational study of patients treated in medical and surgical intensive care units in Boston, Massachusetts. We studied 3,166 patients, age 18 years or higher, who received critical care, survived hospitalization and received a formal standardized evaluation by a Registered Dietitian from the Department of Nutrition at the Brigham and Women’s Hospital between 2004 and 2011. The exposure of interest, malnutrition was considered to be present if the patient was formally diagnosed by a Registered Dietitian with any of the following: nonspecific protein-calorie malnutrition, protein-calorie malnutrition (mild protein-calorie malnutrition, moderate protein-calorie malnutrition, severe protein-calorie malnutrition, or marasmus). Patients were not considered to have to have malnutrition if diagnosed as “not at risk” or “at risk” for developing malnutrition. We included formal Registered Dietitian evaluations from 10 days prior to critical care initiation or up to 2 days after critical care initiation. The primary outcome was unplanned hospital readmission to the Brigham and Women’s or Massachusetts General Hospitals in the 30 days following hospital discharge. The first hospitalization associated with critical care is identified as the index critical care exposure, and a 30-day unplanned readmission was defined as a subsequent unplanned admission to the hospitals under study within 30 days of discharge following the hospitalization associated with the index critical care exposure. Readmissions with DRG codes commonly associated with planned readmissions were excluded. Adjusted odds ratios were estimated by multivariable logistic regression models with inclusion of covariate terms thought to plausibly interact with both nutrition status and mortality post hospital discharge. Adjustments included age, race, gender, Deyo-Charlson Index, patient type (medical versus surgical), sepsis and number of organs with acute failure. Results: Nonspecific malnutrition was recorded in 49.4%, specific malnutrition in 11.5%, and malnutrition was absent in 39.1%. The 30-day post discharge hospital readmission rate was 19.1%. In patients who received critical care and survived hospitalization, specific protein-calorie malnutrition was a robust predictor of 30-day post discharge hospital readmission and remained so following multivariable adjustment. The odds of 30-day post discharge hospital readmission in patients with nonspecific or specific protein-calorie malnutrition were 1.15 (95%CI, 0.94,1.39) and 1.82 (95%CI, 1.38,2.40) compared to that of patients without malnutrition. Specific protein-calorie malnutrition remained a significant predictor of the odds of 30-day post discharge hospital readmission after adjustment for age, sex, race, Deyo-Charlson Index, sepsis and medical/surgical patient type. The adjusted odds of 30-day post discharge hospital readmission in patients with nonspecific or specific protein-calorie malnutrition were 1.13 (95%CI, 0.93,1.38) and 1.73 (95%CI, 1.31,2.28) respectively compared to that of patients without malnutrition. Conclusions: In a large population of adult critical illness survivors, malnutrition near ICU admission is a robust predictor of all cause mortality following hospital discharge. With heightening societal and political interest in cost-effective healthcare delivery, malnutrition may be a prognostic and potentially modifiable marker for patients who are at high risk for unplanned hospital readmission.