Adequacy of prescribed caloric and protein intake and reduction of mortality in critically ill patients with body mass indices <30 kg/m2.

OBJECTIVE:Although the provision of nutrition helps minimize adverse outcomes in most patients in intensive care units (ICUs), little is known about the relative effect of energy and protein delivered on mortality in ICU patients with different ranges of body mass index (BMI). The aim of this study was to examine the relationships between adequacy of dietary energy and protein intakes separately and simultaneously, and short-term mortality in medical ICU patients across four BMI categories. METHODS:We enrolled 1693 patients admitted to a medical center ICU in Taiwan during the period of 2005 to 2011, subcategorizing them by BMI levels: <18.5(n = 418), 18.5-24.9 (n = 889), 25-29.9 (n = 289), and ≥30 kg/m2 (n = 97). Dietary energy and protein intake (DEI and DPI) were defined by the percent of prescribed dosages that each patient actually received: highly adequate (>80%), moderately adequate (60-80%), and inadequate (<60%), during the first 10 d in the ICU. RESULTS:Mean DEI was 1237 kcal/d and DPI 47 g protein/d. Analyzed separately in our multiple regression models, moderately and highly adequate DEI (Ptrends = 0.003-0.026) and DPI (Ptrends = 0.001-0.004) were both significantly correlated with reduced mortality in patients with BMI <18.5, 18.5-24.9, and 25-29.9 kg/m2 but not in those with BMI levels ≥30 kg/m2. With DEI and DPI analyzed simultaneously, only APACHE II scores and DPI levels remained significantly related to reduced mortality in patients with BMI <30 kg/m2. CONCLUSION:Although the adequacy of delivery of prescribed DEI or DPI dosages appeared to be important for reduced risks for mortality in ICU patients with BMI <30 kg/m2 when analyzed separately, DPI had a stronger effect on decreases in ICU mortality when the two were analyzed simultaneously. Further investigation may be needed to study the role of increased protein in improving clinical outcomes.