Design: In this cohort study, we used a controlled interrupted time series design in which the interruption was the declaration of the COVID-19 pandemic in the United States on March 13, 2020. The 300-day monitoring period, which evenly bracketed this declaration, started on October 16, 2019, and ended on August 10, 2020.
Participants: Patients with primary open-angle glaucoma enrolled in an ongoing longitudinal NIH-funded study initiated prior to the onset of the pandemic were selected if they were prescribed ocular hypotensive medication and had adherence data spanning the 300-day period.
Methods: We applied segmented regression analysis using a “slope change following a lag” impact model to obtain the adherence slopes in the periods preceding and following the segmentation. We compared the two slopes using the Davies test.
Main outcome and measure: The main outcome measure was daily adherence to ocular hypotensive medication—defined as the number of doses taken divided by the number of doses prescribed, expressed in percent. Adherence was measured objectively using Medication Event Monitoring System (MEMS) caps. We assessed the associations between change in adherence and demographic, clinical, and psychosocial factors.
Results: The sample included 79 patients (mean age, 71 years [SD, 8 years]). Segmented regression identified a breakpoint at day 28 following the declaration of the pandemic. The slope in the post-breakpoint period (-0.04%/day) was significantly different from zero (P < 0.001) and from the slope in the period preceding the breakpoint (0.006%/day) (P < 0.001). A significant positive association was observed between the Connor-Davidson Resilience score and the change in slope between the pre- and post-breakpoint periods (P = 0.002).
Conclusions and Relevance: Adherence to ocular hypotensive medication worsened during the COVID-19 pandemic and appears to be related to patient resilience. This collateral consequence of the pandemic may translate into vision loss that may manifest beyond its containment.