Association between the severity of symptomatic knee osteoarthritis and cumulative metabolic factors

Background The association between cumulative metabolic syndrome (MS) factors and knee osteoarthritis (KOA) has been highlighted over the past two decades. Aims To clarify the relationship between cumulative MS factors and symptomatic KOA. Methods A cross-sectional survey involving 119 women aged 45–88 years who were scheduled to undergo knee surgery was conducted. They were stratified into tertiles of symptoms as assessed by the Japanese Orthopedic Association score for KOA. Multinomial logistic regressions were performed using the severity of symptomatic KOA as the dependent variable and each MS factor or the cumulative MS factors as the independent variables. Results Logistic regression analyses were performed with the upper tertile of stratified symptoms of subjects used as the reference group. After adjustment for confounders, KOA patients who had two ( p = 0.004) or three or more ( p < 0.0001) MS factors were significantly more likely to have severe symptoms compared to those who had no MS factors. MS factors excluding obesity were similarly analyzed. Even after additional adjustment for body mass index (BMI), KOA patients who had two or more ( p = 0.005) MS factors were significantly more likely to have severe symptoms. Conclusion Among KOA female patients diagnosed using radiographic definition, the severity of symptomatic KOA was significantly associated with hypertension, dyslipidemia, and the number of MS factors after adjustment for age, BMI, strength of the knee extensor, and Kellgren–Lawrence grade. The severity of radiographic KOA was not associated with any MS factor or cumulative MS factors.