Persistence and Adherence With Topical Glaucoma Therapy BETH L. NORDSTROM, PHD, DAVID S. FRIEDMAN, MD, ESSY MOZAFFARI, PHARMD, HARRY A. QUIGLEY, MD, AND ALEXANDER M. WALKER, MD, DRPH ● PURPOSE: The present study describes the patterns and predictors of treatment persistence and adherence among patients who are diagnosed with glaucoma or as glaucoma suspects (based on claims codes). ● DESIGN: A retrospective cohort study using health insurance claims data. ● METHODS: Newly treated individuals with diagnosed glaucoma (n  3623) and suspect glaucoma (n  1677) were obtained from healthcare claims data in the Ingenix Research Database. For each of these two diagnostic groups, we calculated the duration of continuous treat- ment with the initially prescribed medication (persis- tence) and the prevalence of use of the initial medication at various time points (adherence). Four drug classes were included: -blockers, -agonists, carbonic anhy- drase inhibitors, and prostaglandin analogs. ● RESULTS: Nearly one half of the individuals who had filled a glaucoma prescription discontinued all topical ocular hypotensive therapy within six months, and just 37% of these individuals recently had refilled their initial medication at three years after the first dispensing. Prostaglandins were associated with better persistence than any other drug class, which was indicated by hazard ratios for discontinuation of prostaglandins compared with -blockers of 0.40 (95% confidence interval, 0.35– 0.44) for diagnosed patients and 0.44 (95% confidence interval, 0.37– 0.52) for patients with suspect glaucoma. Prostaglandins showed a similar advantage in adherence. Furthermore, patients with diagnosed glaucoma were more likely to adhere to therapy than patients with suspect glaucoma (relative risk  1.11; 95% confidence interval, 1.05–1.18). ● CONCLUSION: Persistence and adherence were sub- stantially better with prostaglandins than with other drug classes, and patients with diagnosed open-angle glaucoma were more likely to adhere to treatment than suspected glaucoma. (Am J Ophthalmol 2005;140: 598 – 606. © 2005 by Elsevier Inc. All rights reserved.) A LTHOUGH THE PREFERRED PRACTICE PATTERN OF the American Academy of Ophthalmology lists medical therapy, laser trabeculoplasty, and surgical treatment as reasonable options for the initial treatment of glaucoma, most patients initially receive topical ocular hypotensives. 1 If topical treatment lowers intraocular pres- sure (IOP) adequately, the patient is intended to remain on therapy indefinitely to improve outcome. 2 Although recent studies clearly have documented that the lowering of IOP decreases the risk of visual field loss 3,4 and slows progression from ocular hypertension to glaucoma, 5 many patients appear to discontinue their use of topical hypo- tensive agents. 6 –13 Most studies of persistence with topical glaucoma med- ications that have been conducted to date have not restricted the study population to patients who were diagnosed with glaucoma or suspect glaucoma. 6 –11 Of the two studies that have imposed diagnostic criteria, one study included only suspects, 12 and the other study was fairly small (260 patients in total) and used prescribing records without ascertaining whether the prescriptions were filled. 13 It is important to investigate persistence of treatment within groups of patients with similar diagnostic status; ocular hypotensives that are prescribed for the treatment of primary open angle glaucoma may be used differently from those given for ocular hypertension with- out optic nerve damage and certainly should be used differently for transient elevations in IOP. In addition, none of the studies that were found in the literature examined both the continuous use of glaucoma medica- tions (persistence) and ongoing use, which allowed for gaps in therapy (adherence). We undertook the present study to investigate the patterns and predictors of treat- Accepted for publication Apr 22, 2005. From Ingenix Epidemiology, Auburndale, Massachusetts (B.L.N.; A.M.W.); Wilmer Institute, Johns Hopkins University, Baltimore, Mary- land (D.S.F.; H.A.Q.); Pfizer, Inc, New York, NY (E.M.) Supported by Pfizer through a research contract with Ingenix (B.L.N.; A.M.W.) and through an unrestricted grant to Johns Hopkins University (D.S.F.;H.A.Q.). Pfizer provided support for this study through a research contract with Ingenix (B.N. and A.W.). Pfizer also provided an unre- stricted grant to Johns Hopkins University (D.F. and H.Q.). One of the authors (E.M.) is employed by Pfizer; he was involved in the study design, interpretation, and writing only as a member of a steering committee; all final decisions were made by the authors not employed by Pfizer. Inquiries to Beth L. Nordstrom, PHD, Ingenix Epidemiology, Riverside Center, Suite 3–120 275 Grove St, Auburndale, MA 02466; fax: 617–244 –9669; e-mail: bnordstrom@epidemiology.com © 2005 BY ELSEVIER INC.ALL RIGHTS RESERVED. 598.e1 0002-9394/05/$30.00 doi:10.1016/j.ajo.2005.04.051