Protein-Energy Wasting: Correlation between Geriatric Nutritional Risk Index and Malnutrition-Inflammation Index

Background: Protein-energy wasting (PEW) in patients with chronic kidney disease (CKD) is common and can be detected using the Malnutrition-Inflammation Score (MIS) and the Geriatric Nutritional Risk Index (GNRI). The latter is easy to estimate; however, its performance in patients with stage 3-4 CKD has not been evaluated. Our aim was to determine the correlation between the GNRI and MIS scales in patients with CKD 3-4. Methods: Cross-sectional study evaluated 44 patients with CKD stages 3-4. The GNRI and MIS scales were applied to classify nutritional risk (MIS: Normal 0-2 points, Mild Malnutrition 3-5, Moderate Malnutrition 6-8, Severe Malnutrition ≥9); GNRI: absent, mild, moderate, severe. Averages ±SD were estimated, and absolute and relative frequencies. The correlation between GNRI and MIS scores was estimated, and the nutritional status was compared using both instruments. A 95% CI was used, with a value of p <0.05. Results: 44 patients were evaluated, with 27% in KDIGO 3a, 27% in KDIGO 3b, and 46% in KDIGO 4. 59% women. The mean BMI was 27.06±5.57. Through electrical bioimpedance, the phase angle was of 5.76±1.42. According to the GNRI scale, 23% of the patients had PEW vs 52% with MIS. The latter classified the patients as: 47% normal, 34% mild PEW, 7% moderate PEW, and 21% severe PEW vs 77% patients as normal, 14% with mild wasting, 7% moderate, and one with severe malnutrition according to GNRI. 57% of the patients had a BMI >25, of which 40% had PEW by MIS vs 20% by GNRI. The correlation between the MIS and GNRI scales was r2= 0.643 (p <0.001), and between BMI <25 and MIS-GNRI was 0.91 (p<0.001). Conclusion: The correlation between MIS and GNRI in this population was moderate due to the high prevalence of obesity; GNRI, by using albumin and weight as main variables, has limited applicability and proper interpretation in obese patients. The correlation between MIS and GNRI increases when these tools are used in patients with a BMI <25.Fig. 1 Correlation between MIS and GNRI