Prevalence of malnutrition in 1760 patients at hospital admission: a controlled population study of body composition.

OBJECTIVE Malnutrition, defined as low or excessive body weight, is associated with increased hospital length of stay and cost of care. The purpose of this study was to determine if fat-free mass (FFM) and body fat (BF) differed between patients at hospital admission in Geneva and Berlin and healthy volunteers, and if there is a difference in the prevalence of low FFM (percentile P<10) and high BF (percentile P>90) between patients and volunteers. METHODS In total, 1760 patients (Geneva: 525 men, 470 women; Berlin: 397 men, 368 women) were evaluated for malnutrition by BMI, serum albumin, and FFM and BF, determined by bioelectrical impedance analysis (BIA), and compared to 1760 healthy volunteers matched for age and height, and further compared to FFM and BF percentiles, previously determined in 5225 healthy adults. RESULTS The prevalence of FFM P<10 was greater in patients than controls. The prevalence of albumin<35 g/l (14.9% and 11.2% in Geneva and Berlin patients, respectively) and BMI<20.0 kg/m(2) was lower than the prevalence of low FFM (31.3% and 17.3%, respectively). The prevalence of high BF in Berlin patients was three-fold the prevalence of volunteers. Twelve and twenty percent of Geneva and Berlin patients, respectively, with normal BMI had high BF, compared to 4% of volunteers. CONCLUSIONS Geneva and Berlin patients had lower FFM and higher BF than age-and height-matched volunteers and a higher prevalence of low FFM and high BF. Serum albumin and BMI underestimated the prevalence of malnutrition in patients at hospital admission. Body composition measurements identified patients with low FFM and low or high BF reserves.