CKD and Acute and Long-Term Outcome of Patients with Peripheral Artery Disease and Critical Limb Ischemia

Background and objectives Despite the many studies showing an association between CKD and a high risk of ischemic events and mortality, the association of CKD with peripheral arterial disease (PAD) still has not been well described. Design, setting, participants, & measurements This large cohort study assessed the association of CKD, even in the earlier stages, with morbidity, short- and long-term outcome, and costs among patients with PAD. Results We identified 41,882 patients with PAD who had an index hospitalization between January 1, 2009, and December 31, 2011. Of these, 8470 (20.2%) also had CKD (CKD stage 2: n=2158 [26%]; stage 3: n=3941 [47%]; stage 4: n=935 [11%]; stage 5: n=1436 [17%]). The ratio of women to men was 1:1.2. Compared with patients without known CKD, those with CKD had higher frequencies of coronary artery disease (1.8-fold higher; P<0.001), chronic heart failure (3.3-fold higher; P<0.001), and Rutherford PAD categories 5 and 6 (1.8-fold higher; P<0.001); underwent significantly fewer revascularizations (0.9-fold fewer; P<0.001); had a nearly two-fold higher amputation rate (P<0.001); had higher frequencies of in-hospital infections (2.1-fold higher; P<0.001), acute renal failure (2.8-fold higher; P<0.001), and sepsis (1.9-fold higher; P<0.001); had a 2.5-fold higher frequency of myocardial infarction (P<0.001); and had a nearly three-fold higher in-hospital mortality rate (P<0.001). In an adjusted multivariable Cox regression model, CKD remained a significant predictor of long-term outcome of patients with PAD during follow-up for up to 4 years (until December 31, 2012; median, 775 days; 25th-75th percentiles, 469-1120 days); the hazard ratio was 2.59 (95% confidence interval, 2.21 to 2.78; P<0.001). The projected mortality rates after 4 years were 27% in patients without known CKD and 46%, 52%, 72%, and 78% in those with CKD stages 2, 3, 4, and 5, respectively. Lengths of hospital stay and reimbursement costs were on average nearly 1.4-fold higher (P<0.001) in patients who also had CKD. Conclusions This analysis illustrates the significant and important association of CKD with in-hospital and long-term mortality, morbidity, amputation rates, duration and costs of hospitalization, in-hospital treatment, and complications in patients with PAD.