Association of non-high-density lipoprotein cholesterol to high-density lipoprotein cholesterol ratio (NHHR) with cardiovascular mortality in peritoneal dialysis patients: a prospective cohort study

Background: The association between non-high-density lipoprotein cholesterol to high-density lipoprotein cholesterol ratio (NHHR) and prognosis in patients with end-stage renal disease (ESRD) remains controversial. The aim of this study is to explore the association of NHHR with cardiovascular disease (CVD) mortality as well as all-cause mortality in peritoneal dialysis (PD) patients. Methods: In this single-center prospective observational cohort study, 1,616 individuals undergoing PD were recruited with a median follow-up duration of 47.6 months. The association of NHHR with overall CVD mortality, as well as atherosclerotic and non-atherosclerotic subtypes, was assessed using competing risk regression models. Additionally, multivariable Cox proportional hazards regression was employed to evaluate the relationship between NHHR and all-cause mortality. Critical baseline covariates were adjusted in these multivariable models. Results: In the end, 552 patients (34.2%) died, of whom 264 (47.8%) died from CVD mortality, corresponding to incidence rates of 71.18 and 34.04 per 1,000 person-years, respectively. In multivariable analyses, competing risk regression model showed no significant association between NHHR and overall CVD mortality. However, each 1- standard deviation (SD) increase in NHHR level was associated with a 35% higher risk of atherosclerotic CVD mortality (sub-distribution hazard ratio [SHR] 1.35, 95% Confidence interval [CI] 1.17-1.56), and a 27% lower risk of non-atherosclerotic CVD mortality (SHR 0.73, 95% CI 0.58-0.93), respectively. Cox regression model indicated that each 1-SD increase in NHHR level was independently associated with a 16% increase in all-cause mortality (HR 1.16, 95% CI 1.06-1.26). Quartile-based analysis reinforced these findings. Conclusion: An elevated NHHR level conferred an increased risk of atherosclerotic CVD and all-cause mortality, yet showed a paradoxical association with reduced non-atherosclerotic CVD mortality in PD patients.