A Gap Analysis Approach to Assess Patient Persistence with Glaucoma Medication

• Published in: American journal of ophthalmology 2007-10, Vol.144 (4), p.520-524
• Main Authors: Lee, Paul P, Walt, John G, Chiang, Tina H, Guckian, Angela, Keener, John
• Format: Article
• Language: English
• Subjects: Amides - administration & dosage; Antihypertensive Agents - administration & dosage; Bimatoprost; Biological and medical sciences; Cloprostenol - administration & dosage; Cloprostenol - analogs & derivatives; Compliance; Drug Prescriptions - statistics & numerical data; Drug stores; Drug Utilization - statistics & numerical data; Glaucoma; Glaucoma - drug therapy; Glaucoma and intraocular pressure; Health Insurance Portability & Accountability Act 1996-US; Humans; Hypertension; Intraocular Pressure - drug effects; Lipids - administration & dosage; Medical sciences; Miscellaneous; Ophthalmology; Patient Compliance - statistics & numerical data; Patients; Pharmacies - statistics & numerical data; Pharmacy; Preferred Provider Organizations - statistics & numerical data; Prostaglandins F, Synthetic - administration & dosage; Retrospective Studies; Studies; Travoprost
• ISSN: 0002-9394; 1879-1891
• DOI: 10.1016/j.ajo.2007.06.023

Purpose To develop an alternative method for analysis of patient persistence with prescribed medications using the prostaglandin class of intraocular pressure (IOP)-lowering drugs as a model. Design A retrospective study of prescription refill patterns. Methods Patients with a pharmacy claim for a 2.5 ml bottle of latanoprost, travoprost, or bimatoprost between September 1, 2002 and December 31, 2002 were identified from a retail pharmacy database and were followed up for 12 months. Three separate analyses defined gaps in therapy as spans in excess of 45, 60, or 120 days without a refill for the same medication. Patients were categorized by the number of gaps in therapy and the cumulative length of gaps. A Kaplan-Meier analysis was conducted using a 120-day allowable refill period. Results For refill periods of 45, 60, and 120 days, 10.6%, 28.6%, and 77.5% of patients, respectively, had no gaps in therapy, and 32.6%, 53.4%, and 86.5%, respectively, had 30 days or fewer off therapy annually. According to the 45-day threshold analysis, 50.7% of patients had three or more gaps vs 18.5% in the 60-day analysis and none in the 120-day analysis. The Kaplan-Meier curve shows 88.6% and 76.1% of patients were persistent for 120 days and one year, respectively. Conclusions Compared with Kaplan-Meier survival curves, the gap analysis approach may better parallel clinical experience with patient persistence, in which patients stop and restart medications for a variety of reasons over time. This method also may help to identify avenues for investigation of lack of persistency among many patients.