Serum Albumin as a Marker of Metabolic Response to Injury and its Role with Calorie Intake Regarding Length of Stay, Readmission Rates and Hospital Survival

Abstract

Background: Studies have shown a relationship between albumin level & hospital mortality, but none have looked at low serum albumin, calorie intake and survival. Aim: To evaluate the relationship between serum albumin level, calorie intake, length of hospital stay (LOS), readmission rates and hospital mortality in a large population of disadvantaged and underinsured patients at a County of Los Angeles Medical Center. Design: Prospective observational study using data collected over a 6-year period of hospital survival, LOS and readmission rate in 11,441 patients. Calorie intake in those 400 patients with serum albumin <1.5 g/dL was collected. Our hypothesis was to test if the relationship of admission serum albumin to mortality was linear or exponential. In addition, in those with a serum albumin <1.5 g/dL, we evaluated calorie intake and hospital survival. Methods: A total of 11,441 patients were included in the dataset. ANOVA and regression analysis were performed. Calorie intake was extracted from dietary and intravenous intake data of each of the 400 patients with an albumin <1.5 g/dL. Results: Serum albumin was obtained within the first 7 days of admission in all patients. Mortality increased in patients with admission serum albumin <3.5 g/dL (8.8% vs 2.3%, p<0.05). Serum albumin was exponentially related to mortality (mortality = 32 / albumin2; p <0.01). The group of patients with albumin <1.5 g/dL had the greatest mortality rate (18%), approximately seven times that of patients with normal serum albumin levels. These patients also had an average LOS of 14.7 days (p<0.05), twice that of patients with normal albumin values. 30-day admission rates for this group were three times greater (6.3% vs. 1.9%, p<0.05). Calorie intake was associated with a dose response curve with regards to hospital mortality. Conclusion: A single measurement of serum albumin identifies patients who are at high risk for prolonged hospital stay, readmission and mortality. Calorie intake may modify mortality risk, but prospective studies are needed.