Loss to follow-up and increase in cup-to-disc ratio among glaucoma patients in the IRIS Registry

To assess the association between loss to follow-up (LTFU) and risk of increase in cup-to-disc ratio (CDR) among a national registry cohort of patients with primary open-angle glaucoma (POAG).

A retrospective longitudinal cohort study.

Patients who had a POAG diagnosis in 2014 and had CDR documented in the IRIS Registry (Intelligent Research in Sight) both in 2014 and 2019.

LTFU was defined as a calendar year or more without an encounter. Log-Poisson regression models were used to estimate the relative risk (RR) and 95% confidence intervals (CIs) for the increase in CDR. A sensitivity analysis was also conducted to address ceiling effects for patients with baseline CDR ≥0.8.

An increase by ≥0.2 in CDR from 2014 to 2019.

Among 208,517 patients, 6.9% had an increase by ≥0.2 in CDR from 2014 to 2019. While most patients (81.6%) maintained follow-up every year, 16.1% were LTFU for 1-2 years, and 2.3% were LTFU for 3-4 years. A lapse of 3-4 years was associated with a 15% higher risk of increase in CDR (adjusted RR [aRR] = 1.15, 95% CI: 1.00-1.32) compared to no lapse in care after accounting for age, sex, race, insurance, smoking status, glaucoma severity, baseline intraocular pressure (IOP), and baseline CDR. For patients with CDR ≥ 0.8 at baseline, risk of increase in CDR by ≥0.05 was also associated with LTFU (aRR = 1.34, 95% CI: 1.11-1.60; lapse of 3-4 years compared to no lapse).

LTFU is an independent risk factor for an increase in CDR among patients with POAG.