title: Increased moxifloxacin utilization associated with an unrestricted addition to a drug reimbursement formulary: A population-based analysis.
abstract: OBJECTIVE
  To determine whether utilization of moxifloxacin, a broad-spectrum fluoroquinolone antibiotic, has changed since its addition to the British Columbia provincial formulary in 2009 and to determine whether utilization was guideline concordant.
  
  
  METHODS
  BC PharmaNet prescriptions for moxifloxacin from 2001 to 2010 were anonymously linked to associated Medical Services Plan fee-for-service practitioner claims for indication-specific analysis. Prescribing trends for adults ≥18 years of age were described using defined daily dose (DDD) per 1000 person-years. Monthly utilization rates were fit to a linear regression model that controlled for seasonal variation to examine the effect of the formulary addition.
  
  
  RESULTS
  Utilization rose more than sevenfold throughout the study period, from 21.3 DDD per 1000 person-years in 2001 to 163.3 DDD per 1000 person-years in 2010. Although the formulary addition was not associated with an immediate increase in utilization (7.5% [95% CI -4.4% to 20.9%]; P=0.226), it was associated with an overall increase in utilization of 2.1% (95% CI 1.3% to 3.0%; P<0.001) for every month after 2009. Overall, only 29% of moxifloxacin prescriptions could be linked to a diagnostic code that was considered to be guideline concordant. In more than one-half of moxifloxacin prescriptions, the patient had not used another antibiotic in the previous 90 days. Among moxifloxacin prescriptions in which another antibiotic had been used in the previous 90 days, 41.5% were prescriptions for an alternative fluoroquinolone.
  
  
  CONCLUSIONS
  The formulary addition was associated with a sustained increase in moxifloxacin utilization over time. Moxifloxacin is often prescribed to patients for indications that are not guideline concordant or to patients who have not previously received first-line antibiotics.
authors.affiliation: Department of Medicine, Division of Infectious Disease, University of British Columbia, Vancouver General Hospital;
authors.forename: Alissa Jade
authors.initials: AJ
authors.lastname: Wright
authors.affiliation: Department of Medicine, Division of Infectious Disease, University of British Columbia, Vancouver General Hospital; ; Faculty of Pharmaceutical Sciences, University of British Columbia;
authors.forename: Fawziah
authors.initials: F
authors.lastname: Marra
authors.affiliation: British Columbia Centre for Disease Control, University of British Columbia, Vancouver, British Columbia.
authors.forename: Mei
authors.initials: M
authors.lastname: Chong
authors.affiliation: British Columbia Centre for Disease Control, University of British Columbia, Vancouver, British Columbia.
authors.forename: Catharine
authors.initials: C
authors.lastname: Chambers
authors.affiliation: Department of Medicine, Division of Infectious Disease, University of British Columbia, Vancouver General Hospital;
authors.forename: William R
authors.initials: WR
authors.lastname: Bowie
authors.affiliation: British Columbia Centre for Disease Control, University of British Columbia, Vancouver, British Columbia ; School of Population and Public Health, University of British Columbia, Vancouver, British Columbia.
authors.forename: David M
authors.initials: DM
authors.lastname: Patrick
keywords: Antibiotic stewardship; Drug monitoring; Drug utilization; Population analysis