The U-Shaped Association of Non-High-Density Lipoprotein Cholesterol Levels With All-Cause and Cardiovascular Mortality Among Patients With Hypertension

Background: Non-high-density lipoprotein cholesterol (non-HDL-C) is a valuable indicator in routine blood lipid tests, but the associations of non-HDL-C with mortality in hypertensive population still remain uncertain. Methods: In the National Health and Nutrition Examination Surveys from 1999 to 2014, participants having hypertension were included and grouped by non-HDL-C levels (< 130, 130-159, 160-189, 190-219, and >= 220 mg/dl). Multivariate Cox regression was conducted for calculation of hazard ratios (HR) and 95% confidence interval (CI). To reveal the relationship between non-HDL-C and mortality, Kaplan-Meier survival curves, restricted cubic spline, linear regression, and subgroup analysis were also applied. Results: A total of 12,169 participants (47.52% males, mean age 57.27 +/- 15.79 years) were included. During average follow-up of 92.5 months, 1,946 (15.99%) all-cause deaths and 422 (3.47%) cardiovascular deaths occurred. After adjusting for confounders, the association of non-HDL-C with mortality was detected as U-shaped. Threshold values were observed at 158 mg/dl for all-cause mortality and 190 mg/dl as to cardiovascular mortality. Below the threshold, every 10 mg/dl increment in non-HDL-C attributed to relatively low all-cause mortality significantly (HR = 0.94, 95% CI: 0.92-0.96). Above the threshold, non-HDL-C has significant positive associations with both all-cause (HR = 1.03, 95% CI: 1.01-1.05) and cardiovascular mortality (HR = 1.09, 95% CI: 1.05-1.14). For subgroups analysis, similar results were found among participants age < 65 years old, non-white population, those were not taking lipid-lowering drugs, and subjects with body mass index (BMI) >= 25 kg/m(2). Conclusion: The U-shaped association was detected between non-HDL-C and mortality among hypertensive population.