Association of product of platelet and neutrophil count with monoclonal gammopathy of undetermined significance: a cross-sectional analysis of the NHANES.

Background: Inflammation indices are emerging predictors of diseases. Monoclonal gammopathy of undetermined significance (MGUS) is a precancerous state and chronic inflammation may drive MGUS progression. This study aimed to evaluate the association between inflammatory markers and MGUS.

Methods: Data from the National Health and Nutrition Examination Survey (NHANES) III and 1999-2004 were collected from 6,383 participants. MGUS subtypes were identified using immunofixation electrophoresis. Seven inflammatory indices [lymphocyte count (LC), neutrophil count (NC), platelet-neutrophil product (PPN), systemic immune inflammation index (SII), platelet-lymphocyte ratio (PLR), and C-reactive protein (CRP)] were calculated. Weighted multivariate regression and subgroup analyses assessed the relationships, reported as odds ratios (ORs) and 95% confidence intervals (CIs).

Results: Of the 6383 patients included in the study, 157 (2.45%) underwent MGUS. There was a significant correlation trend between ln PPN level and the development of MGUS, especially at low levels (OR: 2.62, 95% CI: 1.54-4.75, p-trend = 0.001), while the correlation between PLR level and MGUS was not obvious. In the subgroup analysis, a significant association between PPN level and MGUS was mainly found in the overall population, female sex, non-Hispanic black, non-hypercholesterolemia, non-type 2 diabetes (T2D), high school education or above, and divorced or widowed; however, there was no significant interaction between PPN level and MGUS in each subgroup.

Conclusion: PPN levels were significantly associated with MGUS development. Our study identified PPN as a novel and convenient inflammatory marker with potential clinical relevance. Although preliminary, the observed associations highlight the need for validation through longitudinal studies before considering their clinical applications.