Is CONUT score a prognostic index in multiple myeloma?

Objective: In this study, we aimed to investigate the prognostic effect of the recently popular nutritional indicator, the Controlling Nutritional Status (CONUT) score, in patients diagnosed with Multiple Myeloma. Materials and Methods: Our study included 213 patients who admitted the Hematology department of Pamukkale University Faculty of Medicine Hospital and diagnosed with MM between 2008 and 2023. The demographic data and laboratory data (cbc, serum albumin, total cholesterol, sedimentation, renal dysfunction presence, AST, ALT, total bilirubin, indirect bilirubin, uric acid, LDH, Beta-2 microglobulin, IgG, IgA, IgM, kappa and lambda light chain levels) of individuals meeting the inclusion criteria were reviewed through our hospital's registration system and electronic health records. Immunoglobulin subtypes, R-ISS stages, CONUT scores, overall survival (OS) times and progression-free survival (PFS) times at diagnosis were analyzed. The CONUT score, which is a nutritional indicator, was calculated based on serum albumin level, total cholesterol level, and lymphocyte count. According to the serum albumin level, scores were assigned as follows: ≥3.5 g/dL (0 points), 3-3.49 g/dL (2 points), 2.5-2.99 g/dL (4 points), <2.5 g/dL (6 points); according to lymphocyte count: ≥1600/mm3 (0 points), 1200-1599/mm3 (1 point), 800-1199/mm3 (2 points), <800/mm3 (3 points); according to total cholesterol levels: ≥180 mg/dL (0 points), 140-179 mg/dL (1 point), 100-139 mg/dL (2 points), <100 mg/dL (3 points). By summing the values, the CONUT score was obtained and the degree of malnutrition was evaluated as follows: total score 0-1: Normal, 2-4: Low, 5-8: Moderate, 9-12: High. Results: We categorized the patients with MM diagnosed based on the CONUT scores into four groups: normal (0-1), low (2-4), moderate (5-8), and high (9-12). We determined in survival analyses, the median OS for patients with a normal CONUT score was 66.00 months, for those with a low CONUT score it was 54.00 months, for those with a moderate CONUT score it was 27.00 months, and for those with a high CONUT score it was 12.00 months. The findings were statistically significant (p<0.001). When the data were evaluated for mortality risk by multivariate analysis, we specified that having a moderate CONUT score increased the mortality risk by 2.21 times (p=0.005), and having a high CONUT score increased the risk by 2.38 times (p=0.033). Similarly, when the CONUT score was compared for PFS, the median PFS for patients with a normal CONUT score was 26.00 months, for those with a low CONUT score it was 28.00 months, for those with a moderate CONUT score it was 13.00 months, and for those with a high CONUT score it was 1.00 month. The findings were statistically significant (p=0.001). When the CONUT score was evaluated for progression by multivariate analysis, it was found that having a moderate CONUT score increased the progression risk by 1.85 times (p=0.007) and having a high CONUT score increased the progression risk by 2.01 times (p=0.043). Conclusion: Our study demonstrates that the CONUT score is an independent, useful, and strong prognostic index in patients with MM. However, larger prospective studies with larger sample sizes are needed for long-term reliability and acceptability. Keywords: Multiple Myeloma, CONUT, prognosis, overall survival, progression-free survival