Changes in Ocular Hypotensive Drug Usage for Glaucoma Treatment After Cataract Surgery: A Nationwide Population-based Study in Taiwan

Abstract

Purpose: 

The aims of this study were to observe the changes in the demand for prescriptions of ocular hypertensive drug (OHD) after cataract surgery, to investigate patterns of change in the required OHD amount in open-angle glaucoma (OAG) and angle-closure glaucoma (ACG) cases, and to determine the associated factors related to the change.

Materials and Methods: 

This population-based cohort study using the Taiwan National Health Insurance Research Database enrolled patients with glaucoma who underwent bilateral cataract surgeries within 2 years between 2001 and 2012. The major dependent variables were the total amounts of OHDs prescribed within 1 year before the first cataract surgery and 1 year after the second cataract surgery. We compared the overall change in the required OHD amount before and after cataract surgery and further explored potential factors affecting the change.

Results: 

Among the 440 patients, there were more cases of ACG than OAG (68.6% vs. 31.4%). The total OHD amount prescribed reduced significantly after cataract surgery in patients with OAG (median, from 12 to 6 bottles before and after the surgery, P<0.0001) and ACG (median, from 10 to 3 bottles, P<0.0001), and the reduction was sustained for 5 years. The reduction was significantly larger in patients with ACG and higher demand for OHD (P=0.0157). Among the OAG cases, the reduction was significantly larger in patients who were female individuals (P=0.0138), treated in clinics (P=0.0305), and exhibited high demand for OHD (P=0.0282).

Conclusions: 

The prescriptions of OHDs by glaucoma patients reduced considerably after cataract surgery. Although the reduction proportion of the demand for OHD after cataract surgery was significantly larger in patients with ACG than in those with OAG, the reduction was sustained for 5 years in both types of glaucoma.