To create and validate a statistical model predicting progression of primary open angle glaucoma (POAG) assessed by loss of visual field as measured in mean deviation (MD) using three landmark studies of glaucoma progression and treatment.
A Markov decision analytic model using patient level data described longitudinal MD changes over seven years.
Patient level data from the Collaborative Initial Glaucoma Treatment Study (CIGTS, n=607), the Ocular Hypertension Treatment Study (OHTS, n=148, only those who developed POAG in the first five years of OHTS) and Advanced Glaucoma Intervention Study (AGIS, n=591), the COA model.
We developed a Markov model with transition matrices stratified by current MD, age, race and intraocular pressure categories and used a microsimulation approach to estimate change in MD over seven years. Internal validation compared model prediction for seven years to actual MD for COA participants. External validation used a cohort of glaucoma patients drawn from university clinical practices.
Main Outcome Measures
Change in visual field as measured in MD in decibels (dB).
Regressing the actual MD against the predicted produced an R2 of 0.68 for the right eye and 0.63 for the left. The model predicted ending MD for right eyes of 65% of participants and for 63% of left eyes within 3 dB of actual results at seven years. In external validation the model had an R2 of 0.79 in the right eye and 0.77 in the left at five years.
The COA model is a validated tool for clinicians, patients and health policy makers seeking to understand longitudinal changes in mean deviation in people with glaucoma..