White Blood Cell Count Predicts All-Cause Mortality in Patients with Suspected Peripheral Arterial Disease
Abstract
Objective
We investigated whether markers of inflammation—white blood cell (WBC) count, C-reactive protein (CRP), and lipoprotein-associated phospholipase A2—are associated with mortality in patients referred for noninvasive lower-extremity arterial evaluation.
Methods
Participants (n = 242, mean age 68 years, 54% men) were followed for a median of 71 months. Ankle-brachial index (ABI), WBC count, plasma CRP, and lipoprotein-associated phospholipase A2 were measured at the start of the study. Factors associated with all-cause mortality were identified using Cox proportional hazards.
Results
During the follow-up period, 56 patients (25%) died. Factors associated with higher mortality were greater age, history of coronary artery disease/cerebrovascular disease, lower ABI, higher serum creatinine, and higher WBC count/plasma CRP. In stepwise multivariable regression analysis, ABI, serum creatinine, WBC count, and CRP were associated significantly with mortality. Patients in the top tertile of WBC count and CRP level had a relative risk of mortality of 3.37 (confidence interval [CI], 1.56-7.27) and 2.12 (CI, 0.97-4.62), respectively. However, only the WBC count contributed incrementally to prediction of mortality. Inferences were similar when analyses were limited to patients with peripheral arterial disease (ABI<0.9, n = 114).
Conclusion
WBC count, but not plasma CRP level, provides incremental information about the risk of death in patients referred for lower-extremity arterial evaluation and in the subset of these patients with peripheral arterial disease.
aThe Gonda Vascular Center and Division of Cardiovascular Diseases, Mayo Clinic, Rochester, Minn
bDivision of Biomedical Statistics and Informatics, Mayo Clinic, Rochester, Minn
Requests for reprints should be addressed to Faisal A. Arain, MD, Vascular Medicine Fellow, Gonda Vascular Center and Division of Cardiovascular Diseases, Mayo Clinic, 200 First Street SW, Rochester, MN 55905
Funding: Supported by National Institutes of Health grants HL75794 and HL81331. Dr Arain is supported by the National Institutes of Health Vascular Medicine Training Program K12 grant (HL 083797).
Conflict of Interest: None.
Authorship: All authors had access to the data and played a role in writing this manuscript.
ABSTRACT
