Abstract
Purpose:
Cataract surgery is associated with increased inflammatory mediators, and other retinovascular changes that might increase risk of developing diabetic macular edema (DME) after cataract surgery. We wished to assess the rate of developing DME requiring treatment with intravitreal ranibizumab and the possible impact of cataract surgery in a large cohort for which there was a single electronic platform for capturing data consistently.
Methods:
Multicentre national DR database study with 3458 eyes receiving ranibizumab for DME. Data collected in the course of routine clinical care , anonymised data within an electronic medical record system were extracted remotely from 20 Centres. The minimum dataset included: age, visual acuity at baseline and at all subsequent visits, injection episodes, and timing of cataract surgery. Main Outcome Measures: Rate of developing 'injection-requiring DME' in relation to timing of cataract surgery in the same eye.
Results:
The follow-up period was median [IQR] 1 [0.2,2.3] years. During this period, 469 eyes underwent cataract surgery. The rate of developing 'injection-requiring DME' in this cohort decreased prior to surgery (3.5% for the period 12-9mths prior, 2.4% for 9-6mths prior, 2.3% for 6-3mths prior and 1.3% for 3-0mths prior), but increased sharply after surgery, peaking in the 3-6mths period (9.1% for the 0-3mths period post-op, 12.3% for 3-6mths post-op, 8.5% for 6-9 mths post-op and 5.7% for 9-12mths post-op).
Conclusions:
This real world dataset achieved at a large number of centres across the UK suggests that there may be an increased rate of developing DME requiring treatment with intravitreal ranibizumab. An alternative explanation is that this is purely an issue of visualization, however in the UK access to ranibizumab for DME is based on a minimum OCT-measured central macular thickness, increasing the likelihood that our findings represent a real effect of cataract surgery on DME, rather than being due to improved visualisation alone. It is also possible that this post-operative peak may be compounded by post-operative CME in this relatively high-risk group, and this is the subject of on-going investigation.