Data Sheet 2_HbA1c-to-HDL-C ratio and risk of incident cardiovascular disease among older adults: evidence from a 7-year prospective cohort study in southwestern China.pdf

Multivariable Cox proportional hazards models, restricted cubic spline (RCS), time-dependent area under the receiver operating characteristic curve (AUC), C-statistic and decision curve analysis (DCA) were fitted to estimate the association between HbA1c/HDL-C and CVD risk. Subgroup, sensitivity analyses were performed to verify robustness.</p>Results<p>During a median follow-up of 5.08 years, 207 participants developed incident CVD, with a cumulative incidence of 11.04%.

After fully adjusting for confounding factors, participants in the highest quartile (Q4) of the HbA1c/HDL-C ratio exhibited a significantly elevated risk of incident CVD compared with the lowest quartile (Q1) (HR = 2.111, 95%CI: 1.276–3.170, P = 0.003), whereas the linear trend across quartiles did not reach statistical significance (P_{for trend} = 0.068). RCS analysis revealed a nonlinear dose-response relationship (P_{for overall} < 0.001, P_{for nonlinear} = 0.017), with a data-driven inflection point at an HbA1c/HDL-C ratio of 4.83 (95%CI: 3.55–6.06).

Below this threshold, each unit increment was associated with a 44.10% increase in CVD risk (HR = 1.441, 95%CI: 1.138–1.825, P = 0.002). Incorporation of the HbA1c/HDL-C ratio into a conventional risk factor model enhanced the time-dependent AUC (test-set C-statistic: 0.795 vs. 0.777). DCA demonstrated enhanced net benefit, particularly during mid-to-long-term follow-up.

Subgroup and sensitivity analyses verified the robustness.</p>Conclusions<p>After multivariable Cox regression adjustment, participants in the highest quartile (Q4) of the HbA1c/HDL-C ratio showed a significant association with incident CVD, while the linear trend across Q1 to Q4 was borderline significant. RCS analysis further identified a nonlinear dose–response relationship between HbA1c/HDL-C ratio and incident CVD.

Given its accessibility, low cost, and ease of calculation, the HbA1c/HDL-C ratio may serve as a complementary indicator for community-based CVD risk stratification, particularly in resource-constrained primary care settings. The apparently stronger association observed should be considered exploratory and requires confirmation in larger prospective cohort studies.</p>