Intravitreal Injection Discontinuation Rates High, Loss to Follow-Up Low

Intravitreal injection discontinuation rates are high for patients undergoing the treatments for longer than 7 years, most frequently within the first year, according to a report published in The Canadian Journal of Ophthalmology. However, most of the reasons for discontinuation are attributable to disease or treatment factors and nonmodifiable patient factors, not loss to follow-up.

The researchers looked at the intravitreal injection discontinuation rates of 502 treatment-naive patients (619 eyes; mean age, 81.6±8.4 years; 64.0% women) with neovascular age-related macular degeneration (nAMD) who started treatments between January 2015 and June 2021. The participants underwent 9015 injections, with 23.3% receiving injections in both eyes at some point during the study period. Their mean baseline best-corrected visual acuities (BCVA) were 0.8±0.5 logMAR.

Patients were followed for at least a year. The study found 361 eyes (58.3%) discontinued treatment. Intravitreal injection discontinuation was due to:

• Lack of visual benefit (152) 
• Severe comorbidity or death (82)
• Transferred (33) 
• Stable off active treatment (19)
• Lack of visual benefit plus stable off treatment (14)
• Patient decision (6),
• Ocular comorbidity (4) 
• Lost to follow up (51)

Intravitreal injection discontinuation occurred within the first year in 49% of patients. Of the patients lost to follow-up, or those in the patient decision groups, discontinuation mostly occurred at a treatment interval of 45 weeks (n=17) or 12 weeks (n=17). Another 8 stopped at a 6- to 7-week treatment interval, 9 at an 8- to 9-week interval, and 6 at a 10- to 11-week interval, according to the researchers.

Overall, 59% of participants ceased treatment. Most did so at 7.5 months, a timeline which researchers say align with “a trial of therapy that was stopped due to no improvement in vision.” In fact, the most common reason given for intravitreal injection discontinuation was a lack of any visual benefits. The researchers report that this study shows a reduction in patients with nAMD undergoing anti-VEGF injections lost to follow-up. “Our lost to follow-up rate of 16.5% is lower than those in studies with similar definitions, with reported rates of 22% and 51% in 4-year studies and 57% in a 5-year study,” according to the researchers.

Those who received treatment for at least a year had better baseline and final visual acuities. “This may reflect a tendency toward a longer trial of therapy in patients with better baseline visual acuity to maintain this level of vision,” according to the researchers. “Although there was no improvement in visual acuity from baseline, [central subfield thickness] did show definite improvement with treatment, suggesting that the drugs were effective at obtaining control. These findings reflect the challenges of predicting which patients will have a visual benefit at baseline and highlight the critical need for predictive biomarkers to guide treatment.”

The study was limited by the small size of some intravitreal injection discontinuation subgroups, the multifactorial nature of treatment decisions, and the COVID-19 pandemic, which interrupted the typical practice schedule during the study’s final year.