The UK Diabetic Retinopathy Electronic Medical Record (UK DR EMR) Users Group, Report 2: real-world data for the impact of cataract surgery on diabetic macular oedema.

AIM: To assess the rate of 'treatment-requiring diabetic macular oedema (DMO)' in eyes for the two  years before and after cataract surgery.

METHODS: Multicentre national diabetic retinopathy (DR) database study with anonymised data extraction across 19 centres from an electronic medical record system.

INCLUSION CRITERIA: eyes undergoing cataract surgery in patients with diabetes with no history of DMO prior to study start. The minimum dataset included: age, visual acuity (all time-points), injection episodes, timing of cataract surgery and ETDRS grading of retinopathy and maculopathy.

MAIN OUTCOME MEASURE: rate of developing first episode of treatment-requiring DMO in relation to timing of cataract surgery in the same eye.

RESULTS: 4850 eyes met the inclusion criteria. The rate of developing treatment-requiring DMO in this cohort was 2.9% in the year prior to surgery versus 5.3% in the year after surgery (p<0.01). The risk of 'treatment-requiring DMO' increased sharply after surgery, peaking in the 3-6 months' period (annualised rates of 5.2%, 6.8%, 5.6% and 4.0% for the 0-3, 3-6, 6-9 and 9-12 months' post-operative time periods respectively). Risk was associated with pre-operative grade of retinopathy: risk of DMO in the first year post-operatively being 1.0% (no DR pre-operatively), 5.4% (mild non-proliferative diabetic retinopathy; NPDR), 10.0% (moderate NPDR), 13.1% (severe NPDR) and 4.9% (PDR) (p<0.01).

CONCLUSIONS: This large real-world study demonstrates that the rate of developing treatment-requiring DMO increases sharply in the year after cataract surgery for all grades of retinopathy, peaking in the 3-6 months' postoperative period. Patients with moderate and severe NPDR are at particularly high risk.