The quality of warfarin prescribing and monitoring in Veterans Affairs nursing homes.
OBJECTIVE
To describe the quality of warfarin prescribing and monitoring in Veterans Affairs (VA) nursing homes and to assess the factors associated with maintaining a therapeutic international normalized ratio (INR).


METHODS
Retrospective cohort.


METHODS
Five VA nursing homes.


METHODS
All veterans who received warfarin between January 1 and June 30, 2008, at the nursing homes.


METHODS
Using medical records, the percentage of person-time spent in the target INR range, the proportion of patients with INRs in the therapeutic range on 50% or more of their person-days, and the frequency of INR monitoring were estimated. Multivariable logistic regression was used to identify factors associated with maintaining a therapeutic INR 50% or more of the time.


RESULTS
Over 6 months, 160 patients received 10,380 person-days of warfarin. INRs were in the therapeutic range for 55% of the person-days, and 99% of the INR tests were repeated within 4 weeks of the previous result. On an individual level, 49% of patients had INRs in the target range for 50% or more of their person-days. Achieving this outcome was more likely in patients with prevalent warfarin use than with new use (adjusted odds ratio (AOR)=2.86, 95% confidence interval (CI)=1.06-7.72). Conversely, patients with a history of a stroke (AOR=0.38, 95% CI =0.18-0.80) were less likely to have therapeutic INRs for 50% or more of their days.


CONCLUSIONS
Warfarin appears to be prescribed and monitored effectively in VA nursing home patients. Future studies should focus on increasing time in therapeutic range in patients with poor INR control.
Aspinall
Sherrie L
SL
Veterans Affairs Center for Medication Safety, Hines, Illinois, USA. sherrie.aspinall@va.gov
Zhao
Xinhua
X
Handler
Steven M
SM
Stone
Roslyn A
RA
Kosmoski
Janine C
JC
Libby
Elizabeth A
EA
Francis
Susan Dove
SD
Goodman
David A
DA
Roman
Rebecca D
RD
Bieber
Heather L
HL
Voisine
Jennifer M
JM
Jeffery
Sean M
SM
Hepfinger
Charley A
CA
Hagen
Diane G
DG
Martin
Micki M
MM
Hanlon
Joseph T
JT
D000368:Aged; D000925:Anticoagulants / Q000008:administration & dosage*; D015331:Cohort Studies; D016903:Drug Monitoring; D005260:Female; D006470:Hemorrhage / Q000453:epidemiology; D006801:Humans; D019934:International Normalized Ratio; D008297:Male; D009735:Nursing Homes; D011785:Quality Assurance, Health Care; D012189:Retrospective Studies; D020521:Stroke / Q000097:blood; D014481:United States / Q000453:epidemiology; D014493:United States Department of Veterans Affairs; D014859:Warfarin / Q000008:administration & dosage*
D000925:Anticoagulants; D014859:Warfarin