Medication compliance and disease exacerbation in patients with asthma: a retrospective study of managed care data.
BACKGROUND
Compliance with asthma medications probably results in improved outcomes, but few studies have examined this relationship.


OBJECTIVE
To examine the association between medication compliance and exacerbation in asthmatic patients.


METHODS
Retrospective analysis of a managed care database. The 97,743 participants (aged 6-99 years; mean age, 32.8 years) had asthma and prescriptions for controller medications. Compliance with the index medication (the first controller medication prescribed) was measured using 2 methods: medication possession ratio (MPR), calculated for 365 days after the index date, and number of prescriptions for each index medication. Exacerbation was defined as 1 or more emergency department visits or hospitalizations within 1 year of the index date. Multivariate models were used to determine the odds of exacerbation based on relative compliance for each definition of compliance.


RESULTS
Based on the median MPR, more-compliant patients were less likely to experience exacerbation than less-compliant patients (odds ratio, 0.94; 95% confidence interval, 0.91-0.97; P < .001). Using the 75th percentile MPR, risk of exacerbation was even smaller (odds ratio, 0.89; 95% confidence interval, 0.86-0.92; P < .001). All the cutoff points for compliance (> or = 2 through > or = 6 prescriptions) demonstrated significantly less exacerbations in more-compliant vs less-compliant patients after adjusting for covariates. As the criteria for compliance became more stringent, more-compliant patients became increasingly less likely to have an exacerbation vs less-compliant patients.


CONCLUSIONS
More-compliant asthmatic patients were significantly less likely to experience exacerbation than less-compliant asthmatic patients. These findings demonstrate the importance of improving medication compliance among asthmatic patients to impact outcomes.
Stern
Lee
L
Global Health Outcomes, Analytica International, New York, New York 10016, USA. lstern@AnalyticaIntl.com
Berman
Jeff
J
Lumry
William
W
Katz
Laura
L
Wang
Lujing
L
Rosenblatt
Lisa
L
Doyle
John J
JJ
D000293:Adolescent; D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D018927:Anti-Asthmatic Agents / Q000627:therapeutic use*; D001249:Asthma / Q000188:drug therapy* / Q000503:physiopathology*; D002648:Child; D005260:Female; D006801:Humans; D008297:Male; D008329:Managed Care Programs / Q000706:statistics & numerical data; D008875:Middle Aged; D010349:Patient Compliance; D012189:Retrospective Studies; D014481:United States
D018927:Anti-Asthmatic Agents