Using cost-effectiveness analysis to sharpen formulary decision-making: the example of tiotropium at the Veterans Affairs health care system.
OBJECTIVE
To identify a cost-saving subset of criteria for the use of tiotropium at a Veterans Affairs Medical Center based on a cost-effectiveness analysis with ipratropium as the comparator.


METHODS
Retrospective analysis of electronic medical records for the calendar year 2004 was conducted. The sample was drawn from a population at the Baltimore Veterans Affairs Medical Center that had a confirmed diagnosis of chronic obstructive pulmonary disease (COPD) and had filled prescriptions for ipratropium. The tiotropium sample was based on a modeled cohort of COPD patients who had received tiotropium. The analysis was conducted from the perspective of the Veterans Affairs Health Care System. The outcome was the incremental cost-effectiveness of tiotropium versus ipratropium.


RESULTS
The incremental cost-effectiveness ratio (ICER) was $2360 per avoided exacerbation. Tiotropium cost-effectiveness increased with COPD severity and was cost-saving in patients with very severe disease (ICER = $-1818) and in patients with a previous COPD-related hospitalization (ICER = $-4472). The ICER was most sensitive to the relative effectiveness and price of tiotropium. Results identified the levels of treatment effectiveness and price beyond which tiotropium would become cost-saving relative to ipratropium.


CONCLUSIONS
The results support the existing Veterans Affairs practice of offering tiotropium to patients with COPD-related hospitalizations. Periodic review of the effectiveness data to determine whether tiotropium would be cost-saving in patients with very severe COPD is suggested. Cost-effectiveness analyses that identify practical criteria-for-use should become an integral part of the formulary process.
Onukwugha
Ebere
E
Department of Pharmaceutical Health Services Research, School of Pharmacy, University of Maryland, 220 Arch Street, 12th floor, Baltimore, MD 21201, USA. eonukwug@rx.umaryland.edu
Mullins
C Daniel
CD
DeLisle
Sylvain
S
D000368:Aged; D001993:Bronchodilator Agents / Q000191:economics* / Q000627:therapeutic use; D016001:Confidence Intervals; D003362:Cost-Benefit Analysis / Q000191:economics; D003657:Decision Making; D005260:Female; D005572:Formularies, Hospital as Topic; D006760:Hospitalization / Q000191:economics / Q000706:statistics & numerical data; D006787:Hospitals, Veterans / Q000191:economics*; D006801:Humans; D009241:Ipratropium / Q000191:economics / Q000627:therapeutic use; D008297:Male; D008396:Maryland; D016347:Medical Records Systems, Computerized; D018803:Models, Economic; D029424:Pulmonary Disease, Chronic Obstructive / Q000188:drug therapy* / Q000191:economics; D012129:Respiratory Function Tests / Q000191:economics; D012189:Retrospective Studies; D012602:Scopolamine Derivatives / Q000191:economics* / Q000627:therapeutic use; D012680:Sensitivity and Specificity; D000069447:Tiotropium Bromide; D014481:United States; D014493:United States Department of Veterans Affairs; D014728:Veterans
D001993:Bronchodilator Agents; D012602:Scopolamine Derivatives; D009241:Ipratropium; D000069447:Tiotropium Bromide