Comparison of the Effects of Bimatoprost and a Fixed Combination of Latanoprost and Timolol on 24-Hour Blood Pressure and Ocular Perfusion Pressure

Purpose:To compare the effect of bimatoprost and the fixed combination of latanoprost and timolol (LTFC) on 24-hour systolic (SBP) and diastolic (DBP) holter blood pressure and on 24-hour ocular perfusion pressure (OPP) in glaucoma patients, in a randomized, double-masked, multicentre clinical trial. Methods:Included were patients who were controlled (IOP<21 mmHg) on the unfixed combination of latanoprost and timolol for at least 3 months prior to the baseline visit or patients on monotherapy either with latanoprost or timolol who were eligible for dual therapy not being fully controlled on monotherapy. Supine and sitting position IOPs were recorded at 8 p.m., midnight, 5 a.m., 8a.m., noon and 4 p.m. at baseline, week-6 and week-12 visits; a 24-hour blood pressure curve was obtained with holter (measurements every 15 minutes) at baseline and between week 6 and 12. Comparisons between treatments and within the 2 treatment groups with baseline were carried out with ANOVA. Rates of diastolic OPP <55, <45, <35 mmHg in the 2 groups were calculated and compared using Fisher’s test. Results:Mean baseline SBP and DBP were 136.5 ± 18.3 vs 134.2 ± 20.1 mmHg (p=0.1) and 79.1 ± 10.2 vs 78.2 ± 10.1 mmHg (p=0.4) in the bimatoprost (101 patients) and LTFC (99 patients) groups respectively. At week 12, mean SBP was significantly lower in the group treated with LTFC (p=0.03), while no significant difference in mean DBP was found between the 2 groups. Analysis of diastolic OPP found no significant difference between the 2 groups, and proportions of patients with at least one value of the 24-hour curve below 55, 45 and 35 mmHg were 75%, 46%, 26% and 76%, 47%, 28% in the bimatoprost and LTFC groups respectively (p=0.1). Conclusions:Similar mean DBPs and diastolic OPPs were found after both bimatoprost and the LTFC. In this study, the percentage of "dippers" was considerably higher than the one described in previous studies on the role of perfusion pressure in glaucoma.