title: Impact of the introduction of generic latanoprost on glaucoma medication adherence.
abstract: OBJECTIVE
  To assess possible changes in medication adherence to prostaglandin analog (PGA) regimens among patients with open-angle glaucoma (OAG) after the initial introduction of generic PGAs.
  
  
  METHODS
  Longitudinal cohort analysis.
  
  
  METHODS
  Patients older than 40 years with OAG continuously enrolled in a nationwide managed-care network during 2009-2012 who used PGAs.
  
  
  METHODS
  Mean adherence rates were calculated for topical PGA use during the 18 months before the introduction of generic latanoprost (September 2009-February 2011) and the 18 months after generic latanoprost became available (July 2011-December 2012). The rates were compared between persons who continued to use brand-name PGAs once generic latanoprost became available and others who switched to generic latanoprost. Multivariable logistic regression identified variables associated with an improvement or worsening of adherence of ≥25%.
  
  
  METHODS
  Mean adherence rates and odds of 25% or more improved or worsened adherence (with 95% confidence intervals [CIs]).
  
  
  RESULTS
  A total of 8427 patients met the study eligibility criteria. Compared with persons switching to generic latanoprost, patients who continued taking brand name PGAs were 28% less likely to have improved adherence (odds ratio [OR], 0.72; 95% CI, 0.55-0.94) and 39% more likely to have reduced adherence (OR, 1.39; 1.04-1.86) of ≥25%. Improved adherence after the generic drug's introduction was also associated with higher monthly medication copay in the pregeneric period (P = 0.02), lower copay after introduction of the generic drug (P < 0.0001), and black race (OR, 1.25; 95% CI, 1.04-1.50). Six-hundred twelve patients (7.3%) discontinued all antiglaucoma interventions when generic latanoprost became available.
  
  
  CONCLUSIONS
  Given that cost can significantly deter adherence, switching patients to generic medications may help improve patients' drug-regimen adherence. A considerable number of patients discontinued glaucoma drug use altogether when generic latanoprost became available. Ophthalmologists should work with insurers and pharmacists to prevent such discontinuation of use as generic forms of other PGA agents become available.
authors: Department of Ophthalmology and Visual Sciences, University of Michigan Medical School, Ann Arbor, Michigan. Electronic address: jdstein@med.umich.edu.
authors: Joshua D
authors: JD
authors: Stein
authors: Department of Ophthalmology and Visual Sciences, University of Michigan Medical School, Ann Arbor, Michigan.
authors: Nakul
authors: N
authors: Shekhawat
authors: Department of Ophthalmology and Visual Sciences, University of Michigan Medical School, Ann Arbor, Michigan.
authors: Nidhi
authors: N
authors: Talwar
authors: Department of Clinical, Social, and Administrative Sciences, College of Pharmacy, University of Michigan, Ann Arbor, Michigan.
authors: Rajesh
authors: R
authors: Balkrishnan
mesh_terms: D000287:Administration, Topical; D000368:Aged; D000959:Antihypertensive Agents / Q000627:therapeutic use*; D015331:Cohort Studies; D016527:Drug Costs; D016568:Drugs, Generic / Q000191:economics / Q000627:therapeutic use*; D005260:Female; D005500:Follow-Up Studies; D005902:Glaucoma, Open-Angle / Q000188:drug therapy*; D006801:Humans; D007429:Intraocular Pressure / Q000187:drug effects*; D000077338:Latanoprost; D008297:Male; D008329:Managed Care Programs; D008875:Middle Aged; D016017:Odds Ratio; D009883:Ophthalmic Solutions; D011461:Prostaglandins F, Synthetic / Q000191:economics / Q000627:therapeutic use*; D016903:Drug Monitoring
chemical_list: D000959:Antihypertensive Agents; D016568:Drugs, Generic; D009883:Ophthalmic Solutions; D011461:Prostaglandins F, Synthetic; D000077338:Latanoprost