# Platelet and Lymphocyte-Related Parameters as Potential Markers of Osteoarthritis Severity: A Cross-Sectional Study

## TL;DR

This study explores how blood parameters like platelet and lymphocyte levels relate to the severity of osteoarthritis, suggesting they could help detect the condition early.

## Contribution

The study identifies platelet-to-lymphocyte ratio as a novel potential biomarker for osteoarthritis severity.

## Key findings

- Higher platelet-to-lymphocyte ratio (PLR) is associated with increased odds of moderate/severe osteoarthritis.
- The model achieved 73.1% accuracy in predicting OA severity using PLR and age.
- A 25-unit increase in PLR elevates the odds of higher OA levels by 1.30 times.

## Abstract

Background: Platelets and lymphocytes levels are important in assessing systemic disorders, reflecting inflammatory and immune responses. This study investigated the relationship between blood parameters (platelet count (PLT), mean platelet volume (MPV), lymphocyte count (LINF), and platelet-to-lymphocyte ratio (PLR)) and osteoarthritis (OA) severity, considering age, sex, and body mass index (BMI). Methods: Patients aged ≥40 years were included in this cross-sectional study and divided into groups based on knee OA severity using the Kellgren–Lawrence (KL) grading system. A logistic regression model, adjusted for confounders, evaluated the ability of PLT, MPV, LINF, and PLR to categorize OA severity. Model performance in terms of accuracy, sensitivity, and specificity was assessed using ROC curves. Results: The study involved 245 OA patients (51.4% female, 48.6% male) aged 40–90 years, 35.9% with early OA (KL < 3) and 64.1% moderate/severe OA (KL ≥ 3). Most patients (60.8%) were aged ≥60 years, and BMI was <25 kg/m2 in 33.9%. The model showed that a 25-unit increase in PLR elevates the odds of higher OA levels by 1.30 times (1-unit OR = 1.011, 95% CI [1.004, 1.017], p < 0.005), while being ≥40 years old elevates the odds by 4.42 times (OR 4.42, 95% CI [2.46, 7.95], p < 0.0005). The model’s accuracy was 73.1%, with 84% sensitivity, 52% specificity, and an AUC of 0.74 (95% CI [0.675, 0.805]). Conclusions: Higher PLR increases the likelihood of moderate/severe OA, suggesting that monitoring these biomarkers could aid in early detection and management of OA severity. Further research is warranted to cross-validate these results in larger populations.