title: Natural history of claudication: long-term serial follow-up study of 1244 claudicants.
abstract: OBJECTIVE
  The purpose of this study was to delineate the natural history of claudication and determine risk factors for ischemic rest pain (IRP) and ischemic ulceration (IU) among patients with claudication.
  
  
  METHODS
  We prospectively collected data on 1244 men with claudication during a 15-year period, including demographics, clinical risk factors, and ankle-brachial index (ABI). We followed these patients serially with ABIs, self-reported walking distance (WalkDist), and monitoring for IRP and IU. We used Kaplan-Meier and proportional hazards modeling to find independent predictors of IRP and IU.
  
  
  RESULTS
  Mean follow-up was 45 months; statistically valid follow-up could be carried out for as long as 12 years. ABI declined an average of 0.014 per year. WalkDist declined at an average rate of 9.2 yards per year. The cumulative 10-year risks of development of IU and IRP were 23% and 30%, respectively. In multivariate analysis using several clinical risk factors, we found that only DM (relative risk [RR], 1.8) and ABI (RR, 2.2 for 0.1 decrease in ABI) predicted the development of IRP. Similarly, only DM (RR, 3.0) and ABI (RR, 1.9 for 0.1 decrease in ABI) were significant predictors of IU.
  
  
  CONCLUSIONS
  This large serial study of claudication is, to our knowledge, the longest of its kind. We documented an average rate of ABI decline of 0.014 per year and a decline in WalkDist of 9.2 yards per year. Two clinical factors, ABI and DM, were found to be associated with the development of IRP and IU. Our findings may be useful in predicting the clinical course of claudication.
authors.affiliation: Division of Vascular Surgery, the University of Pittsburgh Medical Center and Veterans Administration Medical Center, PA 15213, USA.
authors.forename: R
authors.initials: R
authors.lastname: Aquino
authors.forename: C
authors.initials: C
authors.lastname: Johnnides
authors.forename: M
authors.initials: M
authors.lastname: Makaroun
authors.forename: J C
authors.initials: JC
authors.lastname: Whittle
authors.forename: V S
authors.initials: VS
authors.lastname: Muluk
authors.forename: M E
authors.initials: ME
authors.lastname: Kelley
authors.forename: S C
authors.initials: SC
authors.lastname: Muluk
mesh_terms: D048909:Diabetes Complications; D018450:Disease Progression; D005080:Exercise Test; D005500:Follow-Up Studies; D006801:Humans; D006973:Hypertension / Q000150:complications; D007383:Intermittent Claudication / Q000145:classification / Q000150:complications* / Q000175:diagnosis / Q000503:physiopathology*; D007871:Leg Ulcer / Q000209:etiology; D008297:Male; D008875:Middle Aged; D015999:Multivariate Analysis; D010146:Pain / Q000175:diagnosis / Q000209:etiology; D010147:Pain Measurement; D010414:Pennsylvania; D016016:Proportional Hazards Models; D012146:Rest; D012307:Risk Factors; D012720:Severity of Illness Index; D012907:Smoking / Q000009:adverse effects; D016019:Survival Analysis; D018608:Ultrasonography, Doppler; D014728:Veterans / Q000706:statistics & numerical data; D016138:Walking