Predictive Value of Glycated Hemoglobin and Body Mass Index for Pretreatment Neuropathy in Patients With Multiple Myeloma

BackgroundPeripheral neuropathy (PN) is detected in up to 62% patients with multiple myeloma (MM) at diagnosis. No specific risk factor for pretreatment neuropathy has been identified.Patients and MethodsWe evaluated 29 sequential patients with MM attending our tertiary care center for peripheral neuropathy at diagnosis using symptoms, clinical examination, and nerve conduction studies (NCSs). Total Neuropathy Score, reduced (TNSr) and Total Neuropathy Score, clinical (TNSc) were calculated, and a score of ≥ 2 in each scale was considered diagnostic of PN. The study was approved by our institutional review board.ResultsWe found that 51.7% (n = 15) and 17.2% (n = 5) of patients had pretreatment neuropathy by TNSr and TNSc scales, respectively. Higher glycated hemoglobin (HbA1C) (P = .022), higher body mass index (BMI) (P = .008), higher serum creatinine levels (P = .023), and higher blood urea levels (P = .006) were associated with neuropathy by TNSr in univariate analysis. Higher blood urea levels (P = .023), higher serum creatinine levels (P = .003), and higher serum β2-microglobulin levels (P = .013) were associated with neuropathy by TNSc in univariate analysis. Higher HbA1c levels (P = .036; odds ratio [OR], 9.46) and BMI (P = .028; OR, 1.78) were associated with neuropathy by TNSr on binomial logistic regression analysis. Cutoffs of 5.6% (sensitivity, 60%; specificity, 71.4%) and 23.7 kg/m2 (sensitivity, 80%; specificity, 71.4%) were obtained for HbA1c (area under the curve [AUC], 0.75) and BMI (AUC, 0.79), respectively, on receiver operating characteristic (ROC) curve analysis to predict neuropathy. The combination of HbA1c ≥ 5.6% and BMI ≥ 23.7 kg/m2 had higher odds of neuropathy by TNSr (OR, 27.0; 95% confidence interval [CI], 2.0-368.4) when compared with either factor alone.ConclusionUse of TNSr, which incorporates electrophysiological abnormalities in addition to clinical manifestations, improves the detection rate of neuropathy. We found that high HbA1c and high BMI together are risk factors for neuropathy at diagnosis in patients with MM.