Are elderly hospitalized patients getting enough protein?

Objectives: To determine the protein requirements of elderly hospitalized patients.

Design: Cross-sectional evaluation of nitrogen balance.

Setting: Short-stay geriatric ward or rehabilitation care unit.

Participants: Thirty-six elderly hospitalized patients (aged 65-99) admitted to short-stay and rehabilitation care units.

Measurements: Resting energy expenditure and nitrogen balance were determined under usual and spontaneous energy and protein intake after subjects were clinically stable (3-5 days after admission). All items consumed over a 3-day period were weighed to determine energy and protein intake.

Results: Energy (23.5+/-6.3 kcal/kg per day) and protein (0.99+/-0.24 g/kg per day) intake were similar in men and women, and nitrogen balance was neutral (0.37+/-2.6 g/day; P=.41 vs a neutral nitrogen balance, i.e., 0 g/d). Half of the patients had a positive nitrogen balance. Plasma C-reactive protein, renal function, nutritional status, and initial diagnosis had no influence on nitrogen balance. In contrast, energy and protein intakes correlated positively with nitrogen balance. Linear regression analysis suggested that an elderly hospitalized patient with an energy intake of 1.31 times resting energy expenditure or greater appears to require a minimum protein intake of 1.06+/-0.28 g/kg per day.

Conclusion: Mean protein intake to reach a neutral nitrogen balance in elderly hospitalized patients is 1.06+/-0.28 g/kg per day, which is higher than current recommendations for healthy elderly people. Safe protein intake (that would be adequate to ensure that 95% of patients remain in positive nitrogen balance) is difficult to establish.