Serum DKK-1 Correlates with Pain Intensity, Flare-Ups, and Bone Mineral Density in Non-Obese Patients with Knee Osteoarthritis: A Single-Center, Cross-Sectional Study

Background: Osteoarthritis, the most common musculoskeletal disorder primarily af-fects people in their mid-40s and older. As the disease progresses, degenerative chang-es occur in the synovial membrane, subchondral bone, and cartilage. Ultimately, the entire joint and its surrounding tissues become structurally and functionally impaired. Several sets of biochemical markers have been proposed to establish a timely diagnosis and anticipate progression. However, only a few of these are routinely used for disease monitoring. Methods: We conducted a prospective, single-center cohort study of 72 patients with knee osteoarthritis. Diagnosis was established on clinical data and radiological find-ings. We examined four cartilage metabolic regulatory factors: the Wnt/β-catenin sig-naling inhibitors serum DKK-1 and sclerostin, RANKL, and OPG, correlating these with disease activity and pain scores (WOMAC, VAS, and KOFUS), radiographic stage, inflammatory molecules and indices, and bone mineral density. Results: DKK-1 levels were higher in the intensive pain group (VAS >5) and were posi-tively correlated with the KOFUS flare-up score throughout the study. This correlation was stronger in individuals with a BMI < 30. Serum DKK-1 levels were higher in pa-tients with lower bone mineral density. No significant modifications in SOST, RANKL, or OPG levels were found. Conclusion: DKK-1 is an indicator of pain and low-grade flare-ups in patients with knee osteoarthritis (OA), being elevated in the early stages of the disease, associated with increasing pain intensity and impaired bone turnover. Early warnings of aug-mentation would be useful for more efficiently exploiting potential disease-modifying treatments.