Cystatin C and eGFRCKD-EPI-CysC: novel biomarkers for renal impairment diagnosis and two-year progression-free survival in multiple myeloma.

To evaluate cystatin C (CysC) and estimation of glomerular filtration rate (GFR) calculated using the formula, CKD-EPI-CysC (eGFR_CKD-EPI-CysC) for renal impairment diagnosis and predicting the prognosis of patients with multiple myeloma (MM). One hundred-fourteen patients with MM and 38 healthy individuals were recruited for the study. Data on clinical characteristics and renal function-related biochemical indicators were collected and analyzed. Patients with MM had increased levels of CysC (1.25 (0.97–2.31) vs. 0.84 (0.80–0.92), respectively, p < 0.001) and decreased levels of eGFR_CKD-EPI-CysC (53.0 (24.4–81.1) vs. 97.2 (87.0–104.5), respectively, p < 0.001), compared with healthy individuals. There were significantly more patients with elevated CysC levels than with elevated sCr levels (64.9% vs. 41.2%, respectively, p < 0.001). The CKD-EPI-CysC formula detected more patients with eGFR < 60 ml/(min × 1.73 m²) than the CKD-EPI-sCr formula (52.63% vs. 37.72%, respectively, p < 0.001). Correlation analysis found that only CysC, eGFR_CKD-EPI-CysC, and eGFR_{CKD-EPI-sCr-CysC} strongly correlated with β₂-microglobulin in group ISS-I. Logistic regression analysis was used to screen CysC (OR = 1.495, 95% CI = 1.097–2.038, p = 0.011) and eGFR_CKD-EPI-CysC (OR = 0.980, 95% CI = 0.967–0.993, p = 0.003) as independent prognostic indicators for 2-year-progression-free survival (PFS) of patients with MM. Receiver operating characteristic curve analysis found that CysC values >1.70 mg/L had 67.6% sensitivity and 65.2% specificity and eGFR_CKD-EPI-CysC values <38.62 ml/(min × 1.73 m²) had 65.2% sensitivity and 67.6% specificity for 2-year PFS of patients with MM. In summary, CysC and eGFR_CKD-EPI-CysC were more sensitive than sCr and eGFR_CKD-EPI-sCr for predicting renal impairment in patients newly diagnosed with MM. Increased CysC and decreased eGFR_CKD-EPI-CysC levels were effective predictors of 2-year PFS of patients with MM. [ABSTRACT FROM AUTHOR]