Association between Low Serum Creatinine Levels and Knee Osteoarthritis in Koreans without Renal Insufficiency

Purpose: This study aimed to investigate the correlation between serum creatinine levels and the presence and severity of radiographic knee osteoarthritis (OA) in individuals aged ≥50 years while adjusting for potential confounders.

Materials and methods: Cross-sectional data from the 2009-2011 Korea National Health and Nutrition Examination Survey comprising 3428 individuals aged ≥50 years were utilized. The Kellgren-Lawrence (K-L) grading scale was used to assess the radiographic presence and severity of knee OA. Logistic regression and receiver operating characteristic analyses were used to investigate the association between serum creatinine levels and the presence of knee OA, whereas ordinal regression was used to assess the impact of creatinine levels on knee OA severity.

Results: The presence of radiographic knee OA conferred by low serum creatinine levels was found to be significant in both sexes [odds ratio (OR), 0.118; 95% confidence interval (CI), 0.045-0.314, p<0.001 for men; OR, 0.148; 95% CI, 0.040-0.549, p=0.004 for women]. Low serum creatinine was significantly associated with knee OA-graded K-L severity in each sex-based group [β, -1.923; standard error, 0.478; p<0.001 for men and β, -1.532; SE, 0.575; p=0.008 for women].

Conclusion: Low serum creatinine level was associated with a higher presence of knee OA in both men and women, and was also linked to the severity of the disease. These findings suggest that the serum creatinine level may be a potential biomarker for assessing the presence and severity of knee OA.