Five-Year Risk Prediction Models for Peripheral Artery Disease in Patients With Chronic Kidney Disease

Patients with chronic kidney disease (CKD) have an increased risk of peripheral artery disease (PAD), yet no PAD risk-prediction models currently exist for this population. We developed and internally validated 5-year PAD risk-prediction models for individuals with CKD.

Prospective cohort study.

3,076 patients with CKD without PAD from the Chronic Renal Insufficiency Cohort (CRIC) study.

Clinically available variables, ankle-brachial index (ABI), and non-routinely measured cardiovascular disease biomarkers assessed at baseline.

New-onset adjudicated clinical PAD event or an ABI ≤0.9 at an annual follow-up visit.

Cox proportional hazards models were applied to estimate 5-year risk of incident PAD from baseline. Model performance was assessed by discrimination, calibration, and net reclassification improvement. All models were internally validated using Monte Carlo cross-validation.

Participants had a mean age of 57 years; 55% were male and 40% were Black. Over 5 years, 512 developed PAD. Compared with an ABI-only model that included ABI, age, and sex (area under the receiver operating characteristic curve [AUC], 0.697; 95% CI, 0.688-0.713), a clinical model using routine variables showed similar discrimination (AUC, 0.682; 95% CI, 0.669-0.691; P = 0.09). Adding ABI to the clinical model improved discrimination (AUC, 0.721; 95% CI, 0.709-0.736; P <0.001). The biomarker-enhanced model achieved an AUC of 0.724 (95% CI, 0.711-0.745), which was not significantly different from the clinical model with ABI. Both the clinical model with ABI and the biomarker-enhanced model were well calibrated and improved reclassification of non-events compared with the ABI model (19.7%; 95% CI, 17.5-22.0% and 22.2%; 95% CI, 19.8-24.5%, respectively).

Lack of external validation.

A PAD risk prediction model that combines clinical variables with ABI improves the identification of patients with CKD at high risk for PAD better than ABI alone.