Association between non-high-density lipoprotein cholesterol to high-density lipoprotein cholesterol ratio and mortality in cancer patients: a cohort study

With the improvement in long-term survival of cancer patients, cancer is increasingly being regarded as a chronic disease, whose long-term prognosis is influenced not only by the tumor itself but also significantly constrained by non-cancer factors. Dyslipidemia, especially the imbalance between non-high-density lipoprotein cholesterol (non-HDL-C) and high-density lipoprotein cholesterol (HDL-C), has been suggested to be associated with cancer prognosis. However, the specific association between the non-HDL-C to HDL-C ratio (NHHR) and mortality risk in cancer patients remains unclear. This study aims to investigate the relationship between NHHR and all-cause, cardiovascular, and cancer-specific mortality in cancer patients, providing a scientific basis for clinical risk assessment and management. This cohort study included 3524 cancer patients from the National Health and Nutrition Examination Survey 1999–2018. Weighted multivariable Cox models were used to evaluate the associations between NHHR and mortality. Dose–response relationships were examined using restricted cubic splines and piecewise Cox models. Sensitivity and subgroup analyses were further conducted to assess the robustness of the findings. Restricted cubic splines revealed a U-shaped association between NHHR and both all-cause and cardiovascular mortality, with the lowest risk observed at NHHR values of 3.33 and 3.02, respectively. Threshold effect analysis showed that when baseline NHHR was below the inflection points, NHHR was negatively associated with all-cause mortality (HR: 0.79, 95% CI: 0.71–0.88) and cardiovascular mortality (HR: 0.74, 95% CI: 0.58–0.94). Conversely, when baseline NHHR exceeded the inflection points, NHHR was positively associated with all-cause mortality (HR: 1.44, 95% CI: 1.20–1.73) and cardiovascular mortality (HR: 1.72, 95% CI: 1.20–2.45). No significant associations were observed between NHHR and cancer-related mortality. Subgroup and sensitivity analyses showed consistent results, with no significant interactions. In cancer patients, NHHR exhibited a U-shaped association with all-cause and cardiovascular mortality, with the respective inflection points at 3.33 and 3.02. No significant association was detected between NHHR and cancer-related mortality.