Long-Term Cannabis Use and Risk of Postoperative Proliferative Vitreoretinopathy.

IMPORTANCE

Proliferative vitreoretinopathy (PVR) is a major cause of retinal detachment (RD) repair failure, resulting in poor visual outcomes. Cannabis use continues to increase globally and may affect PVR development through its anti-inflammatory and neuroprotective properties, although this association remains unclear.

OBJECTIVE

To assess the risk of developing PVR among patients with concomitant cannabis use who underwent primary RD repair.

DESIGN, SETTING, AND PARTICIPANTS: This retrospective cohort study examined data from electronic health records for a multicenter research network extracted for the period February 1, 2005, to February 1, 2025. Participants were patients who underwent initial RD repair with pars plana vitrectomy (PPV) with or without scleral buckle (SB), primary SB, or pneumatic retinopexy. The records were used to identify patients diagnosed with concomitant cannabis-related disorder together with confirmatory testing of cannabis in urine or blood compared with a control group without documented use. Exclusion criteria were a history proliferative diabetic retinopathy or less than 6 months of follow-up.

EXPOSURES

Primary RD repair and cannabis-related disorder.

MAIN OUTCOME MEASURES

Relative risk (RR) of developing PVR and requiring a subsequent complex RD repair at 6 months and 1 year of follow-up.

RESULTS

After propensity score matching, each cohort had 1193 patients. The mean (SD) age was 53.2 (16.1) years; 1662 were male (69.7%), 641 were female (26.9%), and for 83 patients (3.5%), the sex was unknown. At 6 months, patients with concomitant cannabis use with RD repaired by any method had a reduced risk of developing subsequent PVR (25 events [2.10%] vs 52 events [4.36%]; RR, 0.48; 95% CI, 0.30-0.77; P = .002) and requiring complex RD repair (37 [3.10%] vs 60 [5.03%]; RR, 0.62; 95% CI, 0.41-0.92; P = .02) when compared with controls. Similar results were observed at 1 year for both outcomes.

CONCLUSIONS AND RELEVANCE

Patients who underwent initial repair for RD with concomitant cannabis use were less likely to develop PVR and require subsequent complex RD repair compared with matched patients without documented cannabis exposure; however, the absolute difference in rates was small. While this protective association noted with cannabis use could be due to the population using it rather than an effect of the cannabis itself, the findings suggest that cannabis use might have a role in reducing PVR development. Intervention trials would be needed to try to control for confounding factors.