A recent study published in Medicina (Kaunas) has highlighted the potential of the platelet-to-lymphocyte ratio (PLR) as a valuable marker for assessing disease activity in patients with ankylosing spondylitis (AS). The study found that PLR, when incorporated into a multivariable model alongside traditional inflammatory markers, independently predicted active disease and improved the ability to discriminate between active and inactive states.
The platelet-to-lymphocyte ratio reflects changes in platelet and lymphocyte counts associated with acute inflammatory and prothrombotic conditions. While widely studied in cancer and other immune-mediated disorders, its role in rheumatic diseases has been increasingly recognized. Large observational studies have suggested that alterations in PLR can provide insight into the severity of systemic inflammation and help predict complications such as infections and related comorbidities.
In this retrospective observational study, researchers analyzed data from 196 patients with AS. Active disease was defined as a Bath Ankylosing Spondylitis Disease Activity Index (BASDAI) score of 4 or higher. The study evaluated demographic variables, laboratory parameters, hematological indices, and extra-articular manifestations. Using LASSO regression with ten-fold cross-validation, key predictors were identified and entered into a multivariable logistic regression model, with performance evaluated using receiver operating characteristic (ROC) curve analysis.
Among the participants, 97 patients (49%) met criteria for active disease. LASSO regression highlighted erythrocyte sedimentation rate (ESR), white blood cell count, red cell distribution width (RDW), PLR, and selected extra-articular manifestations as relevant predictors. In multivariable analysis, ESR, white blood cell count, and PLR were independently associated with active disease, while RDW showed a borderline association. The final model demonstrated good discriminative ability, achieving an area under the curve (AUC) of 0.77.
Researchers emphasized that PLR, an easily obtainable and inexpensive index derived from routine blood counts, contributed meaningfully to the model and enhanced discrimination between active and inactive disease beyond conventional inflammatory markers alone. This finding supports a complementary role for PLR in routine clinical assessment of AS, particularly given the limitations of acute-phase reactants in consistently reflecting clinical activity in this condition.
The authors noted that while the results are promising, further prospective studies with external validation are needed to confirm the generalizability of these findings. Additionally, formal decision-analytic evaluation would be required before PLR could be fully integrated into clinical decision-making frameworks.
Overall, this study suggests that PLR could serve as a practical and cost-effective tool for improving disease activity assessment in ankylosing spondylitis, potentially helping clinicians better tailor treatment strategies and monitor patient outcomes.
References
- Kaymaz-Tahra S, Taşkın C, Tanoglu A. Hematological Indices as Potential Biomarkers of Disease Activity in Ankylosing Spondylitis: LASSO-Based Multivariable Modelling. Medicina (Kaunas). 2026 Mar 6;62(3):497.
- Gasparyan AY, Ayvazyan L, Mukanova U, Yessirkepov M, Kitas GD. The Platelet-to-Lymphocyte Ratio as an Inflammatory Marker in Rheumatic Diseases. Ann Lab Med. 2019 Jul;39(4):345-357.