Randomized, observer-blinded study comparing the effectiveness of latanoprost mon otherapy versus pilocarpine with timolol in open-angle glaucoma and ocular hypertension

Abstract

Objectives : To compare the effectiveness in intraocular pressure (IOP) reduction between latanoprost monotherapy versus pilocarpine with timolol in open-angle glaucoma and ocular hypertension whose IOP was not controlled on timolol alone. Design : Multi-site, randomized, observer-blinded, parallel-group, controlled trial. Setting : Bhumipol Adulyadej Hospital, Ramathibodi Hospital, Rajavithi Hospital, Somdej Pra Pinklao Hospital and Pramongkutklao Hospital Participants : Seventy one adult patients with open-angle glaucoma or ocular hypertension who were inadequately controlled with timolol enrolled in the study, while 68 patients completed the study. Intervention : After a 2-week run-in of timolol twice daily, eligible patients were allocated into 2 groups by stratified randomization. One group received latanoprost monotherapy while the other received combination therapy of pilocarpine and timolol. Examination was performed at baseline, 2-week, 6-week and 12-week follow up. Outcome measures : Main outcome was diurnal IOP reduction from baseline. Secondary outcomes were success rate of treatment (final IOP <15, <18 and <21 mmHg), response rate of treatment (IOP reduction from baseline >10%,>20%%,>30% and >40%) and cost-effectiveness analysis in both treatment groups. Results : The mean diurnal IOP reduction from baseline was greater in 36 patients in the latanoprost group than that in 35 patients in the pilocarpine plus timolol group (7.34+2.02(SD) VS 5.29+2.91 mmHg. The mean difference in diurnal IOP reduction between the two groups was 2.1 mmHg with 95% CI 0.632 to 3.553, p = 0.005). Ocular and systemic side effects in both groups were mild and comparable. For success rate of treatment, this study showed that more patients in the latanoprost group reached a target IOP <18 mmHg., and reached a reduction in diurnal IOP>30%, than in the control group. Conclusion : This study confirms that latanoprost monotherapy can lower IOP significantly more than the combination of pilocarpine and timolol, in patients with inadequately controlled IOP with timolol alone; and both regimens are generally well-tolerated. For economic consideration, this paper shows that when considered target IOP <15 mmHg., both groups have nearly equal cost-effectiveness. But when considered target IOP<18 and <21 mmHg., the combination of pilocarpine and timolol has more cost-effectiveness. For decision making what drug will be used in individual patient, clinician may assess not only cost-effectiveness but also quality of life and compliance of the patients.