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 radio-graphic 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 com-prising 3428 individuals aged >= 50 years were utilized. The Kellgren-Lawrence (K-L) grading scale was used to assess the radio-graphic presence and severity of knee OA. Logistic regression and receiver operating characteristic analyses were used to investi-gate 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 [beta, -1.923; standard error, 0.478; p<0.001 for men and beta, -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.