Dyslipidemia and risk of osteonecrosis of the femoral head: A large-scale propensity score-matched cohort study.

Background

ONFH is associated with corticosteroid use and alcohol, both disrupting lipid metabolism. Whether dyslipidemia is associated with ONFH risk remains unclear.

Methods

We conducted a retrospective cohort study using a nationwide electronic health record database comprising 47 academic healthcare organizations. Patients aged 18-75 diagnosed with dyslipidemia from 2016 to 2019 formed the Dyslipidemia cohort (n = 1,571,192); those without formed the No Dyslipidemia cohort (n = 17,870,238). Patients with prior ONFH, corticosteroids, alcohol-related disorders, lupus erythematosus, hematologic malignancies, and other established ONFH etiologies were excluded. After 1:1 propensity score matching for age, sex, obesity, diabetes, and hypertensive diseases, each cohort comprised 1,519,388 patients. The primary outcome was incident ONFH (ICD-10-CM M87.05) at 1, 3, and 5 years.

Results

ONFH risk was consistently higher in the Dyslipidemia cohort: RR 1.95 (95% CI 1.137-3.343; p = 0.013) at 1 year, 1.79 (1.464-2.189; p < 0.001) at 3 years, and 1.62 (1.440-1.815; p < 0.001) at 5 years. At 5 years, ONFH occurred in 0.049% versus 0.031% of matched controls. The E78.1 hypertriglyceridemia subgroup carried the highest risk (RR 2.33; p = 0.002), followed by hypercholesterolemia (RR 1.56) and mixed hyperlipidemia (RR 1.53). Sensitivity analysis in statin-naive cohorts yielded stronger estimates, supporting robustness.

Conclusion

Dyslipidemia remained associated with increased ONFH risk after excluding established competing etiologies. Hypertriglyceridemia showed the highest point estimate, requiring confirmation given limited events. Clinicians should maintain awareness of ONFH in symptomatic dyslipidemia patients; the low absolute risk does not support routine screening.