0173: Association Between the Ratio of Non-high-density Lipoprotein Cholesterol to High-density Lipoprotein Cholesterol and All-cause Mortality Risk in Patients with Rheumatoid Arthritis: A Survival Analysis Based on NHANES Data

Background/Purpose: The Non-High-Density Lipoprotein Cholesterol to High-Density Lipoprotein Cholesterol Ratio (NHHR) has emerged as a promising marker for atherosclerosis, yet its relationship with all-cause mortality in individuals with rheumatoid arthritis (RA) remains poorly understood. This study aims to explore the association between NHHR and mortality in adults with RA.

Methods: Data from the National Health and Nutrition Examination Survey (NHANES) spanning 2007 to 2016 were analyzed, with participants stratified into quartiles based on their NHHR levels. Key covariates included age, gender, body mass index (BMI), C-reactive protein (CRP), and the presence of comorbidities. Subgroup analyses were conducted to assess how the association between NHHR and mortality risk varied across different age groups, sexes, and comorbidity profiles, with interaction effects tested using likelihood ratio tests. Multivariable Cox proportional hazards models were applied to estimate the relationship between NHHR and all-cause mortality risk. Kaplan-Meier survival curves were generated to visualize survival differences among NHHR quartiles, and restricted cubic spline models were employed to explore potential non-linear associations. Sensitivity analyses were also performed to evaluate the robustness of the findings by excluding extreme NHHR values.

Results: Significant variations in baseline characteristics were observed across NHHR quartiles, including differences in age, BMI, cholesterol levels, and comorbidities. Higher NHHR values were associated with increased BMI, total cholesterol, and CRP levels, while individuals in the lowest NHHR quartile showed a higher prevalence of hypertension, diabetes, and coronary heart disease (CHD). NHHR was inversely associated with CHD and showed a positive association with diabetes, though the latter lost significance after adjusting for covariates. A U-shaped relationship was identified between NHHR and all-cause mortality in RA patients, with a risk threshold around 0.575. Kaplan-Meier analysis indicated improved survival with increasing NHHR levels (Log-rank P=0.00013), particularly among older adults (HR = 0.18) and cancer survivors (HR = 0.18). The initial associations were attenuated after covariate adjustment, and sensitivity analyses confirmed the robustness of the findings (bias = −0.024).

Conclusion: NHHR has emerged as a valuable prognostic marker in RA, demonstrating a U-shaped relationship with all-cause mortality, with a critical threshold of 0.575. Its predictive capacity supports the early identification of high-risk individuals, enabling personalized interventions to enhance patient survival and optimize RA management strategies.