Oberved time between precription refill for newer ocular hypotenive agent: the effect of bottle ize

Purpoe To decribe precription refill pattern of ocular hypotenive therapie and to meaure difference among refill rate acro bottle ize. Deign Retropective, population-baed, cohort tudy. Method Thi tudy included patient dipened bimatoprot, brimonidine, dorzolamide/timolol, latanoprot, timolol gel (XE) 0.5%, or travoprot between January 1, 1996, and March 30, 2002. The initial fill date wa identified for the cohort-defining ocular hypotenive, and the number of day between each ubequent refill wa calculated. The analyi wa repeated in patient with at leat four refill to evaluate potential bia. Decriptive and urvival analye evaluated difference in refill rate acro bottle ize. Reult In the 27,387 patient contributing up to four evaluable refill equence, the amount of drug contained in bottle did not predict the number of day between fill. Patient dipened larger bottle typically refilled ooner than drop-count tudie would predict; reult for patient with at leat four refill (n = 12,976) confirmed thee finding. urvival analyi demontrated that the bottle ize trend held acro clae of therapy. Compared with 5.0-ml bottle, patient dipened 10.0-ml and 15.0-ml bottle returned for refill at approximately 1.5 time the expected rate. When average wholeale price were applied to refill interval for elected agent, a 45% exce cot per month wa found for the larger bottle ize (10.0 ml v 5.0 ml or 5.0 ml v 2.5 ml). Concluion Expected refill pattern predicted by bottle ize and mean number of drop do not reflect oberved refill pattern. Patient dipened larger bottle ize return for refill much ooner than expected, regardle of the cla of therapy.