A large-scale retrospective evaluation of patients with new-onset proliferative diabetic retinopathy (PDR) found greater risk of pars plana vitrectomy (PPV), vitreous hemorrhage (VH), and tractional retinal detachment (TRD) over 5 years of follow-up among those who underwent panretinal photocoagulation (PRP) monotherapy vs anti-VEGF monotherapy, though the incidences of each complication were relatively low overall.
Study Design
This retrospective cohort study used aggregated electronic health record (EHR) data of patients with new-onset PDR (January 2003–September 2023) to evaluate outcomes following treatment with either PRP monotherapy or anti-VEGF monotherapy. Patients were propensity-matched for age, gender, race, baseline hemoglobin A1c, body mass index, and use of systemic insulin or other injectable diabetic medications into 2 groups for comparison: a PRP monotherapy cohort and an anti-VEGF monotherapy cohort (N = 12,040). All patients had a minimum of 6 months of follow-up after treatment; patients treated with a combination of PRP and anti-VEGF injections were excluded. The main outcome measures were the incidences of VH, TRD, or PPV at 1, 3, and 5 years after initiating therapy.
Outcomes
At 5 years, PRP monotherapy was associated with higher rates of TRD (relative risk [RR] 2.76), VH (RR 1.72), and PPV (RR 1.18) than anti-VEGF monotherapy. Overall, the incidence of PPV was relatively low in both cohorts, with 548 patients (9%) requiring PPV in the PRP monotherapy cohort vs 465 patients (8%) in the anti-VEGF monotherapy cohort. The mean number of injections given among the anti-VEGF monotherapy cohort was 3.8 injections at 1 year and 6.7 injections at 5 years.
Limitations
The study is limited by the retrospective nature of the report and reliance on accurate coding data from an EHR database. The study excluded patients who were lost to follow-up after initial treatment, a factor that may influence outcomes as prior studies have confirmed the importance of treatment compliance in patients treated with anti-VEGF monotherapy. Moreover, the study excluded patients who received a combination of PRP and anti-VEGF injections and cannot control for biases that may have influenced a physician's decision to proceed with PRP vs anti-VEGF monotherapy at the outset of treatment.
Clinical Significance
The current study identified a higher relative risk of VH, TRD, and need for PPV in patients treated with PRP monotherapy, mirroring the findings of the Diabetic Retinopathy Clinical Research Network (DRCR.net) Protocol S study, a prospective, randomized trial that first noted that patients treated with PRP monotherapy may be more likely to require PPV surgery than patients receiving anti-VEGF therapy.1 Additional studies will be helpful in further refining the risk of vision-threatening complications of PDR after PRP and anti-VEGF therapy, helping clinicians counsel patients and weigh the relative risk and benefits of each treatment modality.
Financial Disclosures: Dr. M. Ali Khan discloses financial relationships with Allergan, Apellis Pharmaceuticals, Genentech (Consultant/Advisor); Regeneron Pharmaceuticals (Grant Support).
Reference
1 Writing Committee for the Diabetic Retinopathy Clinical Research Network. JAMA. 2015;314:2137–2146.