Comparison of an anticoagulation clinic with usual medical care: anticoagulation control, patient outcomes, and health care costs

Arch Intern Med. 1998 Aug 10-24;158(15):1641-7. doi: 10.1001/archinte.158.15.1641.


Background: The outcomes of an inception cohort of patients seen at an anticoagulation clinic (AC) were published previously. The temporary closure of this clinic allowed the evaluation of 2 more inception cohorts: usual medical care and an AC.

Objective: To compare newly anticoagulated patients who were treated with usual medical care with those treated at an AC for patient characteristics, anticoagulation control, bleeding and thromboembolic events, and differences in costs for hospitalizations and emergency department visits.

Results: Rates are expressed as percentage per patient-year. Patients treated at an AC who received lower-range anticoagulation had fewer international normalized ratios greater than 5.0 (7.0% vs 14.7%), spent more time in range (40.0% vs 37.0%), and spent less time at an international normalized ratio greater than 5 (3.5% vs 9.8%). Patients treated at an AC who received higher-range anticoagulation had more international normalized ratios within range (50.4% vs 35.0%), had fewer international normalized ratios less than 2.0 (13.0% vs 23.8%), and spent more time within range (64.0% vs 51.0%). The AC group had lower rates (expressed as percentage per patient-year) of significant bleeding (8.1% vs 35.0%), major to fatal bleeding (1.6% vs 3.9%), and thromboembolic events (3.3% vs 11.8%); the AC group also demonstrated a trend toward a lower mortality rate (0% vs 2.9%; P= .09). Significantly lower annual rates of warfarin sodium-related hospitalizations (5% vs 19%) and emergency department visits (6% vs 22%) reduced annual health care costs by $132086 per 100 patients. Additionally, a lower rate of warfarin-unrelated emergency department visits (46.8% vs 168.0%) produced an additional annual savings in health care costs of $29 72 per 100 patients.

Conclusions: A clinical pharmacist-run AC improved anticoagulation control, reduced bleeding and thromboembolic event rates, and saved $162058 per 100 patients annually in reduced hospitalizations and emergency department visits.

Publication types

  • Comparative Study

MeSH terms

  • Aged
  • Anticoagulants / adverse effects
  • Anticoagulants / therapeutic use*
  • Emergency Service, Hospital / economics
  • Emergency Service, Hospital / statistics & numerical data
  • Female
  • Health Care Costs / statistics & numerical data*
  • Hemorrhage / epidemiology*
  • Hospitalization / economics
  • Hospitalization / statistics & numerical data
  • Humans
  • Male
  • Outcome Assessment, Health Care*
  • Outpatient Clinics, Hospital* / economics
  • Outpatient Clinics, Hospital* / statistics & numerical data
  • Thromboembolism / epidemiology*
  • Thromboembolism / prevention & control
  • Warfarin / adverse effects
  • Warfarin / therapeutic use*


  • Anticoagulants
  • Warfarin