Hypocaloric, high-protein nutrition therapy in older vs younger critically ill patients with obesity

Older patients require more protein than younger patients to achieve anabolism, but age-associated renal dysfunction may limit the amount of protein that can be safely provided. This study examined whether older, critically ill trauma patients with obesity can safely achieve nitrogen equilibrium and have positive clinical outcomes similar to younger obese patients during hypocaloric, high-protein nutrition therapy.

Adult patients with traumatic injury and obesity (body mass index [BMI] >30 kg/m(2)), admitted to the Presley Trauma Center from January 2009 to April 2011, were evaluated. Patients were targeted to receive hypocaloric, high-protein nutrition therapy (<25 kcal/kg ideal body weight [IBW]/d and >2 g/kg IBW/d of protein) for >10 days. Patients were stratified as older (≥60 years) or younger (18-59 years).

Seventy-four patients (33 older, 41 younger) were studied. Older and younger patients were similar in BMI and injury severity. When given isonitrogenous regimens (2.3 ± 0.2 g/kg IBW/d), nitrogen balance was similar between older and younger patients (-3.2 ± 5.7 g/d vs -4.9 ± 9.0 g/d; P = .363). Older patients experienced a greater mean serum urea nitrogen concentration than younger patients (30 ± 14 mg/dL vs 20 ± 9 mg/dL; P = .001) during nutrition therapy. Clinical outcomes were not different between groups.

Older critically ill trauma patients exhibited an equivalent net protein response as younger patients during hypocaloric, high-protein nutrition therapy. Older patients are at greater risk for developing azotemia. Close monitoring is warranted.