Introduction:
Chronic kidney disease (CKD) is common in patients with peripheral arterial disease (PAD), but patients with severe CKD have been excluded from many trials and no objective performance goals exist for patients with PAD and CKD. We sought to analyze the association between severity of CKD and cardiovascular and limb-related outcomes among patients with PAD.
Methods:
We reviewed records of all patients at our institution who underwent lower extremity angiography between 2006 and 2013. We analyzed outcomes including mortality, major adverse cardiovascular event (MACE) rate, and major adverse limb event (MALE) rate according to clinical stage of CKD, determined by calculating each patient’s glomerular filtration rate using the Cockcroft-Gault equation. We used Cox proportional hazard modeling to account for covariates, along with Bonferroni correction for multiple comparisons.
Results:
Of 773 patients, 45% had CKD stage 3-5. The patients had a median age of 67, were 58% male, 51% diabetic, and 57% presented with critical limb ischemia (CLI). During a median follow-up time of 3.2 years, patients with higher stages of CKD had an increased rate of death (Figure 1, p<0.001). CKD stages 4 and 5 were significant predictors of mortality in a multivariate model (HR 3.2 and 2.4 vs. CKD 1, P<0.001 and P<0.01, respectively). An analysis of MACE by CKD stage demonstrated similar results (CKD 4 HR 2.2, p<0.01; CKD 5 HR 2.0, p<0.01). CKD stage also predicted MALE in a univariate analysis (p<0.01), driven by increased limb events among patients with CKD stage 5 (p<0.01). However, CKD stage did not demonstrate a significantly increased hazard of MALE in a multivariate Cox model.
Conclusions:
Patients with PAD who also have CKD have increased rates of adverse outcomes. This relationship seems to be more robust for major cardiovascular events and overall mortality than for major limb events. Future studies should investigate how management of PAD should differ for patients with CKD.
Comparison between four equations for the estimation of glomerular filtration rate in predicting future cardiovascular events and the existing peripheral arterial disease