AIM: E-prescribing can help prevent off-label usage
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“Little is known about the factors that contribute to off-label prescribing that may determine systematic differences in treatment outcome,” wrote Tewodros Eguale, MD, MSc, departments of epidemiology, biostatistics and occupational health, and colleagues from McGill University in Montreal. “The indication for treatment needs to be inferred by reviewing either health problems documented in the patient's chart or diagnostic codes entered in physician surveys. For off-label use, the reason for treatment is, therefore, difficult to discern.”
The researchers used the Medical Office of the XXI Century EHR network in Quebec, Canada, where documentation of treatment indication is mandatory to conduct a systematic investigation of the risks and benefits of off-label use beyond single drugs.
Between January 2005 and December 2009, 113 primary care physicians wrote 253,347 electronic prescriptions for 50,823 patients. Each drug indication was classified as on-label or off-label according to the Health Canada drug database. They identified off-label uses lacking strong scientific evidence. Alternating logistic regression was used to estimate the association between off-label use and drug, patient, and physician characteristics.
The prevalence of off-label use was 11 percent; of the off-label prescriptions, 79 percent lacked strong scientific evidence, they found. Off-label use was highest for central nervous system drugs (26.3 percent), including anticonvulsants (66.6 percent), antipsychotics (43.8 percent) and antidepressants (33.4 percent).
“Drugs with three or four approved indications were associated with less off-label use compared with drugs with one or two approved indications (6.7 percent vs 15.7 percent),” Eguale and company wrote. “Drugs approved after 1995 were prescribed off-label less often than were drugs approved before 1981 (8 percent vs 17 percent). Physicians with evidence-based orientation were less likely to prescribe off-label, a 7 percent reduction per 5 points in the evidence section of the Evidence-Practicality-Conformity Scale.”
“Our findings indicate that off-label prescribing is common in primary care and varies by drug class, the number of approved indications for the drug, the age of the drug, patients' sex, and physicians' attitude toward evidence-based medicine,” the authors concluded. “EHRs can be used to document treatment indication at the time of prescribing and may pave the way for enhanced postmarketing evaluation of drugs if linked to treatment outcomes.”