Protein-energy malnutrition: an integral approach and a simple new classification

A new approach to the classification of protein-energy malnutrition (PEM) in adults is proposed. Three widely accepted measurements, triceps skinfold (TSF), mid-arm muscle circumference (MAMC) and serum albumin (SA) were evaluated simultaneously as representative of the three main body nutritional compartments, that is, fat, muscle protein and visceral protein, respectively. These measurements were carried out in a group of 1709 healthy controls (1038 men and 671 women) living a normal life in the geographical area served by our hospital, in order to define the standard values (50th percentile) of the chosen variables for different age and sex groups. The lower limits of normal values were obtained by calculating the 5th percentile for each age and sex group and were expressed as the percentage of the 50th percentile. Once the standards and lower limits of normality were established, the chosen variables were incorporated into a tridimensional Cartesian system, the origin of the three axes (point 0) being the lower limits of normality (5th percentile). Each axis was then divided into positive (optimal) and negative (suboptimal) zones. This provided eight theoretical possibilities of protein-energy nutritional status. In order to define completely the nutritional status in a particular individual, the degree of severity for each variable should be added (mild, moderate and severe). This quantification can be represented with a point in the corresponding nutritional space. This classification was used to assess the nutritional status in 135 consecutive GI hospital in-patients (82 men and 53 women, mean age 48.23 years) at the time of admission, and in a group of 50 consecutive GI out-patients (28 men and 22 women, mean age 47.98 years) when seen for the first time at a NHS Gastroenterology Clinic. Only 32 per cent of the GI in-patients fulfilled the criteria of being well-nourished. The prevalence of PEM in this group was 68 per cent, the predominant types being mixed and kwashiokor-like (35 and 24 per cent, respectively). The prevalence of PEM in the GI out-patient group was 18 per cent, with a total absence of mixed types. Statistical analysis was performed between nutritional measurements among the three groups studied, as well as for the prevalence of PEM in different diseases among in-patients. This series was compared with other reported series, using the same nutritional variables but a different approach.(ABSTRACT TRUNCATED AT 400 WORDS)