Determinants of selective cyclooxygenase-2 inhibitor prescribing: are patient or physician characteristics more important?
BACKGROUND
Little is known about which factors influence the widespread use of selective cyclooxygenase (COX)-2 inhibitors. We examined the relative effects of patient risk factors for gastrointestinal toxicity, other patient characteristics, and physician prescribing preferences on the decision to prescribe a selective COX-2 inhibitor.


METHODS
We retrospectively studied a cohort of 28,190 Medicare beneficiaries who were continuously enrolled in a large, state-run pharmacy benefits program that reimbursed for selective COX-2 inhibitors and nonselective nonsteroidal anti-inflammatory drugs (NSAIDs) without restrictions. Half of the study sample filled a prescription for a selective COX-2 inhibitor and the other half for a nonselective NSAID. Multivariable logistic regression models were developed to predict COX-2 inhibitor use.


RESULTS
Seventeen percent of patients using a COX-2 inhibitor had no identifiable risk factor for NSAID-associated gastrointestinal toxicity, compared with 23% of those using a nonselective NSAID. Established risk factors (age > or =75 years, history of gastrointestinal hemorrhage or peptic ulcer disease, or concomitant warfarin or oral glucocorticoid use) were all significant predictors of COX-2 inhibitor use, but a multivariable model including only these risk factors discriminated poorly between the two patient groups (C statistic = 0.55). Adding other patient clinical and demographic characteristics to the model somewhat improved this association (C statistic = 0.66); however, when physician prescribing preference was included, the model had excellent ability to discriminate between the two treatment groups (C statistic = 0.83).


CONCLUSIONS
Established risk factors for NSAID-associated gastrointestinal toxicity were poor predictors of who was prescribed a selective COX-2 inhibitor; in contrast, physician prescribing preference was an important determinant.
Solomon
Daniel H
DH
Division of Pharmacoepidemiology and Pharmacoeconomics, Brigham and Women's Hospital, Harvard Medical School, Boston, Massachusetts 02115, USA. dhsolomon@partners.org
Schneeweiss
Sebastian
S
Glynn
Robert J
RJ
Levin
Raisa
R
Avorn
Jerry
J
D000368:Aged; D000369:Aged, 80 and over; D000894:Anti-Inflammatory Agents, Non-Steroidal / Q000009:adverse effects / Q000627:therapeutic use; D001172:Arthritis, Rheumatoid / Q000139:chemically induced; D015331:Cohort Studies; D016861:Cyclooxygenase Inhibitors / Q000009:adverse effects / Q000627:therapeutic use*; D011307:Drug Prescriptions; D005260:Female; D005767:Gastrointestinal Diseases / Q000139:chemically induced; D006801:Humans; D016015:Logistic Models; D008297:Male; D010003:Osteoarthritis / Q000139:chemically induced; D010414:Pennsylvania / Q000453:epidemiology; D010817:Physician-Patient Relations; D011237:Predictive Value of Tests; D012189:Retrospective Studies; D012307:Risk Factors
D000894:Anti-Inflammatory Agents, Non-Steroidal; D016861:Cyclooxygenase Inhibitors