Estimation of calorie and protein intake in aged patients: validation of a method based on meal portions consumed

Malnutrition is highly prevalent in hospital, mainly in geriatric, wards. Weight loss results from a negative energy balance, a situation where energy intake does not match energy requirements. Estimates of patient calorie consumption are not performed routinely because of technical difficulties. We performed three studies to investigate the meal-portion (MP) method as a tool for estimating calorie and protein intakes in clinical situations.

The MP method was designed to estimate calorie and protein consumption from the portion of the food items actually eaten by the patient, which is evaluated at the time plates and dishes are cleared away. Study 1 tested accuracy of the MP method in 50 meals by comparison to food weighing. Study 2 evaluated the validity of estimates obtained by a physician, a member of nursing staff, and a dietician in 30 elderly patients. Study 3 evaluated the robustness and feasibility of the method by comparing estimates obtained by nursing staff (after 1 year of practice with no additional training) and that of a dietician.

Comparison of estimates and true values (obtained by weighing) showed a mean difference of -2 kcal/-0.8 g of protein from evaluations of one-half portions of food (50 meals) and -7 kcal/-1.0 g of protein from one-quarter portions of food; the difference was only significant for protein and one-quarter portions (p =.03). When evaluations were performed by observers of different professional categories (nursing staff, physicians, and dieticians) on actual meals consumed by 30 elderly people afflicted with disease, no statistical differences were shown. This interobserver agreement remained, regardless of the cognitive or physical status of the patient. A third study, performed after 1 year of no additional training, showed that the MP method is robust, but prone to clerical errors.

Valid estimates of calorie and protein consumption can be obtained with the MP method, quoting in one-half portions. Quality controls are required both at the food production site (to avoid propagation of errors arising from food composition) and in data collection (to eliminate clerical mistakes). These results suggest that the MP method could be a tool for estimating calorie and protein intakes in many clinical situations.