Predictive value of uric acid to high-density lipoprotein cholesterol ratio for cardiometabolic multimorbidity in middle-aged and older adults: a nationwide prospective cohort study

Background Cardiometabolic multimorbidity (CMM) is an escalating public health challenge. The uric acid-to-high-density lipoprotein cholesterol ratio (UHR) is a composite biomarker reflecting metabolic disturbance, but prospective evidence regarding the association between UHR and CMM remains limited. Methods This prospective cohort study included 7,435 adults aged ≥ 45 years from CHARLS followed from 2011 to 2018. Cox proportional hazards models and restricted cubic spline analyses were used to examine the associations of UHR and cumulative UHR (CumUHR) with cardiometabolic multimorbidity (CMM). Receiver operating characteristic (ROC) curves compared the predictive performance of UHR and CumUHR with that of uric acid (UA) and high-density lipoprotein cholesterol (HDL-C) alone. Subgroup and sensitivity analyses were conducted to test the robustness of the findings. Result Among the 7,435 participants, 1,748 developed CMM. Kaplan–Meier analysis showed that the cumulative event rate of CMM increased progressively across UHR quartiles (log-rank P  < 0.001). In the fully adjusted model, the highest UHR quartile (Q4) was associated with a significantly increased risk of CMM compared with the lowest quartile (Q1) (HR = 1.48, 95% CI 1.27–1.77). When cumulative exposure was considered, elevated CumUHR remained an independent predictor of CMM (HR = 1.26, 95% CI 1.15–1.39). Restricted cubic spline analyses further demonstrated significant nonlinear associations of both UHR and CumUHR with CMM risk, with inflection points observed around 8.5 for UHR and 35.7 for CumUHR. Furthermore, ROC analysis showed that the composite indicators UHR (AUC = 0.747) and CumUHR (AUC = 0.749) had better predictive performance for CMM than their individual components, UA (AUC = 0.745) and HDL-C (AUC = 0.744) alone. Conclusion Higher UHR and CumUHR levels were independently associated with an increased risk of CMM in middle-aged and older adults. As simple composite indicators integrating UA and HDL-C, UHR and CumUHR may provide additional value for identifying individuals at elevated cardiometabolic risk and improving early risk stratification for CMM.