Association between atherogenic index of plasma and microvascular complications in patients with type 2 diabetes achieving low-density lipoprotein cholesterol targets: a real-world cohort study

Abstract

Background Despite achieving low-density lipoprotein cholesterol (LDL-C) targets, patients with type 2 diabetes mellitus (T2DM) remain at significant risk for microvascular complications. We aimed to investigate whether the atherogenic index of plasma (AIP), a marker of atherogenic dyslipidaemia, is associated with these complications in a real-world cohort of patients with controlled LDL-C. Methods We conducted a retrospective cohort study using electronic health records from community health centres in Shenzhen, China (2018–2024). We included 16,469 participants with T2DM and LDL-C<2.6 mmol/L at baseline, categorising them into tertiles (T1–3) based on baseline AIP. The primary outcome was a composite of incident diabetic retinopathy, diabetic nephropathy, and diabetic peripheral neuropathy, identified via ICD-10 codes. We used multivariable Cox proportional hazards models to assess associations. Results During a median follow-up of 4.6 years, 1,056 participants developed microvascular complications. We observed a graded association between AIP tertiles and the risk of microvascular complications. Participants in T3 had a significantly higher risk of total microvascular complications than those in T1 (hazard ratio (HR) = 1.34; 95% confidence interval (CI) = 1.15–1.56), while T2 showed no statistically significant increase in risk (HR = 1.10; 95% CI = 0.94–1.28). Specifically, compared to T1, T3 participants had significantly higher risks of diabetic nephropathy (HR = 1.62; 95% CI = 1.30–2.01) and diabetic peripheral neuropathy (HR = 1.39; 95% CI = 1.13–1.70), while no statistically significant association was found for diabetic retinopathy risk (HR = 1.23; 95% CI = 0.93–1.63). In contrast, compared with T1 participants, those in T2 had higher risks of nephropathy (HR = 1.28; 95% CI = 1.02–1.59), but no statistically significant associations were found for diabetic peripheral neuropathy or diabetic retinopathy. Conclusions We found that AIP is independently associated with increased risk of microvascular complications, particularly diabetic nephropathy and diabetic peripheral neuropathy, even in T2DM patients achieving LDL-C targets. These results suggest that AIP may serve as a simple, lipid-based marker to help identify patients with residual microvascular risk beyond conventional LDL-C control.