[Nutritional risk in surgery evaluated by body mass index adjusted or not to elderly patients]

Standard body mass index cut-off points for malnutrition are routinely used for adults independently of their age. The hypothesis of this study was that a cut-off point higher than the usual for the diagnosis of malnutrition might be more precise to access the nutritional risk of aged surgical patients.

To evaluate the morbimortality in aged surgical patients and its association with nutritional status assessed by body mass index using either the standard and a higher cut-off point for malnutrition.

All patients admitted for operative procedures (n = 1,912) were allocated to either two groups: <65 years (n = 1,627) or >65 years old (n = 285). The body mass index was used to access the nutritional status. Two different cut-off points for malnutrition (18.5 or 24 kg/m(2)) were used in the group of older patients. Endpoints of the study were length of stay, morbidity and mortality.

Length of stay was higher in patients over 65 years (6 [1-75] days vs. 4 [1-137] days). Both postoperative complications (37/285; 13.0% vs. 109/1627; 6.7%; OR 2.1; IC95% 1.40-3.09) and deaths (15/285; 5.3% vs. 34/1627; 2.1%; OR 2.6; IC95% 1.40-4.84) were most common in the older group. Using a higher cut-off (24 kg/m(2)), the length of stay (8 [1-75] days vs. 4 [1-43] days), postoperative complications (28/152; 18.4% versus 9/133; 6.8%; OR 3,1; IC95% 1.41-6.86) and re-operations (16/152; 10.5% versus 3/133; 2.2%; OR 5.1; IC95% 1.45-17.91) were greater in malnourished patients. However these correlations were not statistically significant with the cut-off point for malnutrition in 18.5 kg/m(2).

Morbimortality is higher in surgical patients over 65 years old. In these, the cut-off point set in 24 kg/m(2) was most associated with the occurrence of postoperative complications, re-operations and length of stay.