Wide clinic-level variation in adherence to oral diabetes medications in the VA.
BACKGROUND
While there has been extensive research into patient-specific predictors of medication adherence and patient-specific interventions to improve adherence, there has been little examination of variation in clinic-level medication adherence.


OBJECTIVE
We examined the clinic-level variation of oral hypoglycemic agent (OHA) medication adherence among patients with diabetes treated in the Department of Veterans Affairs (VA) primary care clinics. We hypothesized that there would be systematic variation in clinic-level adherence measures, and that adherence within organizationally-affiliated clinics, such as those sharing local management and support, would be more highly correlated than adherence between unaffiliated clinics.


METHODS
Retrospective cohort study.


METHODS
VA hospital and VA community-based primary care clinics in the contiguous 48 states.


METHODS
444,418 patients with diabetes treated with OHAs and seen in 158 hospital-based clinics and 401 affiliated community primary care clinics during fiscal years 2006 and 2007.


METHODS
Refill-based medication adherence to OHA.


RESULTS
Adjusting for patient characteristics, the proportion of patients adherent to OHAs ranged from 57 % to 81 % across clinics. Adherence between organizationally affiliated clinics was high (Pearson Correlation = 0.82), and adherence between unaffiliated clinics was low (Pearson Correlation = 0.04).


CONCLUSIONS
The proportion of patients adherent to OHAs varied widely across VA primary care clinics. Clinic-level adherence was highly correlated to other clinics in the same organizational unit. Further research should identify which factors common to affiliated clinics influence medication adherence.
Northwest Center for Outcomes Research in Older Adults, VA Puget Sound Health Care System, Seattle, WA, USA. Christopher.Bryson@va.gov
Chris L
CL
Bryson
David H
DH
Au
Matthew L
ML
Maciejewski
John D
JD
Piette
Stephan D
SD
Fihn
George L
GL
Jackson
Mark
M
Perkins
Edwin S
ES
Wong
Elizabeth M
EM
Yano
Chuan-Fen
CF
Liu
D000284:Administration, Oral; D000368:Aged; D000369:Aged, 80 and over; D000554:Ambulatory Care Facilities / Q000706:statistics & numerical data*; D015897:Comorbidity; D003924:Diabetes Mellitus, Type 2 / Q000188:drug therapy* / Q000523:psychology; D005260:Female; D006302:Health Services Research / Q000379:methods; D006787:Hospitals, Veterans / Q000706:statistics & numerical data; D006801:Humans; D007004:Hypoglycemic Agents / Q000008:administration & dosage* / Q000627:therapeutic use; D008297:Male; D055118:Medication Adherence / Q000523:psychology; D008875:Middle Aged; D010044:Outpatient Clinics, Hospital / Q000706:statistics & numerical data; D011320:Primary Health Care / Q000706:statistics & numerical data; D012189:Retrospective Studies; D014481:United States; D014493:United States Department of Veterans Affairs; D014728:Veterans / Q000523:psychology*; D016903:Drug Monitoring
D007004:Hypoglycemic Agents