Significance of Common Blood Test Indexes in the Diagnosis and Prognosis of Multiple Myeloma.

Background: The goal of this study is to explore the clinical value of routine tests in multiple myeloma (MM).

Methods: A total of 179 MM patients, newly diagnosed in our hospital from January 2010 to December 2018 (case group), as well as 352 cases of healthy individuals (control group) were evaluated. Albumin (Alb), globulin (Glb), albumin/globulin (A/G), creatinine (Cr), calcium (Ca), hemoglobin (Hb), lactate dehydrogenase (LDH), platelet count (Plt), and platelet distribution width (PDW) were compared between the analyzed groups. Respective tests were screened by forward selection. Thereafter, screened out indicators were identified through logistic regression analysis. Risk prediction nomogram, area under curve (AUC), calibration, decision curve analysis (DCA), and clinical impact curve (CIC) were further performed. At the same time, routine test indicators of MM patients for stage and subtype diagnosis, were compared. A correlation analysis between these test indicators and respective disease stages was performed. High stage group and low stage groups were subsequently compared to define the predictive value of single and combined indicators of disease severity.

Results: Except for Ca, the difference between the case and control groups for all other blood indicators was statistically significant (p < 0.05). Moreover, the difference in positive rate(s) was statistically significant (p < 0.05). The receiver operating characteristic (ROC) curve of Alb, Hb, and PDW harbored robust discrimination (AUC = 0.960) and appropriate calibration. The DCA and CIC showed that the resulting nomogram had a superior net benefit in predicting MM. Among all indicators, only LDH was statistically reduced in MM patients at ISS stages I, II, and III (p < 0.05). Interestingly, the ISS stage of respective MM patients was positively correlated with Cr (τ = 0.392), while it was negatively correlated with Hb (τ = -0.364). Alb, Glo, A/G, and Hb were significantly distinct between heavy chain (IgG, IgA) and LC, while few significant differences were found between the ISS stages. Lastly, the AUC (0.828) for Cr was greater than that for all other single and combined indicators.

Conclusions: The effective application of major indicators measured in routine blood tests can provide important clues for the diagnosis and prognosis of MM.