[Nutritional status evaluation in maintenance hemodialysis patients]

Abstract

Protein-calorie malnutrition is a common complication and an important predictive factor for mortality in patients with end-stage renal disease on maintenance dialysis. Therefore, nutritional status needs to be regularly assessed in these patients by using several methods. If malnutrition is diagnosed, its causes should be thoroughly searched for and properly treated.

Material and method: This cross-section study aimed at evaluating the nutritional status and the possible risk factors for malnutrition in 149 (82 men) hemodialysis patients by anthropometry, biochemical tests and bioelectrical impedance analysis (BIA). The patients' height (H), post-dialysis body weight (BW), mid-arm circumference (MAC), tricipital skin-fold thickness (TST) were measured and a 3-category subjective global assessment (SGA) was performed. Body mass index (BMI), mid-arm muscle circumference (MAMC), corrected mid-arm muscle area (cMAMA) and anthropometry-estimated percent body muscle mass (% AMM) were calculated from the above measurements by using specific equations. Biochemical tests included protein equivalent of nitrogen appearance (nPNA), and predialysis serum albumin, creatinine, total cholesterol, bicarbonate, and hemoglobin (Hb) levels. We used BIA to estimate body composition - i.e. percent body fat (% BBF), fat-free mass (% FFM), body cell mass (% BCM), extracellular mass (% ECM), muscle mass (% BMM)--and the phase angle (PhA). T-test was used to make comparisons and Pearson coefficient to analyze the correlations. P < 0.05 was considered statistically significant.

Results: The male patients had a higher mean muscle mass--as estimated by serum creatinine (9.8 s 8.3 mg/dl; P < 0.0001) and by % BMM (41.7% vs 34.7%)--and a lower fat mass--as estimated by TST (0.95 cm vs 1.2 cm; P = 0.016) and by % FAT (16.7% vs 31.3%; P < 0.0001) than the female patients. Age was found to be positively correlated with BMI (P = 0.001), but inversely correlated with % BCM (P = 0.013) and with % AMM (P = 0.003). Patients with diabetes had lower % BCM than those without diabetes (32.9 vs 35.9%; P = 0.041). The presence of heart failure was associated with significantly reduced MAMC (22.0 vs 23.6 cm2; P = 0.045), % AMM (28.5 vs 32.1; P = 0.021), % BCM (33.0 vs 36.1% ; P = 0.034), BMM/H2 (8.6 vs 9.4 kg/m2; P = 0.013), nPNA (1.17 vs 1.34 g/kg-d ; P = 0.047), serum albumin (39.7 vs 42.4 g/l; P = 0.010), serum creatinine (8.1 vs 9.4 mg/dl; P = 0.008) and Hb (10.5 vs 11.2 g/dl; P = 0.017). The serum Hb level was positively correlated with BMI (P = 0.005), BMM/H2 (P = 0.009), serum albumin (P = 0.002) and serum creatinine (P = 0.011). Also, patients with category B-SGA were older (63.7 vs 50.1 y.o.; P < 0.0001) and had more heart failure (42% vs 13%; P = 0.013) than those with category A-SGA. In hemodialysis patients, advancing age, diabetes, heart failure and decreasing Hb levels are associated with worse nutritional status, as estimated by anthropometry, biochemical markers and BIA. Whether treatment of comorbidities such as heart disease and anemia may improve nutritional status in these patients is an important issue that deserves further research.