Abstract
Purpose:
Clarification is needed for the effects of bariatric surgery and its changes to glycated haemoglobin (HbA1c) levels on the evolution of diabetic complications, as there are case reports of worsening diabetic retinopathy (DR) despite improved HbA1c levels. We conducted a retrospective, observational clinical study to evaluate the post-operative changes to DR in our patient cohort. More data on this subject will help to redefine future screening schedules for this group of patients.
Methods:
Data from a specialist unit in the UK was collected for 23 Caucasian adults (median age 50years) with type 2 diabetes mellitus that underwent bariatric surgical procedures. Pre-operative and post-operative visual acuity (VA), weight, HbA1c data (median 9 months post-operative) and annual Diabetic Retinal Screening Service (DRSS) fundus photographs (median 43months post-operatively) were analysed. Patients with no DRSS data due to failed attendance were not included.
Results:
No significant change in VA was found due to DR over the post-operative screening period. 18 patients had improved HbA1c levels post-operatively including 9 patients that achieved non-diabetic HbA1c levels of ≤41mmol/mol (≤5.9%). However 1 of those patients developed new background DR in one eye 7 months after achieving a non-diabetic HbA1c level. 10 patients demonstrated worse DR over the post-operative screening period including 1 patient who developed bilateral sight-threatening diabetic maculopathy by 44months post-operatively. 9 patients demonstrated improved DR over the post-operative screening period. 7 patients achieved a significant weight loss (≥25% of pre-operative weight) by median 10 months post-operatively. None of those patients developed worse DR compared to their pre-operative data and 1 patient demonstrated an improvement from proliferative DR pre-operatively to pre-proliferative DR by 36 months, sustained at 48 months post-operatively.
Conclusions:
Our data suggest bariatric surgery does not guarantee a long-term prevention or improvement to DR, despite improved or normalised HbA1c levels. However ≥25% post-operative weight loss was protective for our cohort. Asymptomatic DR changes occurred that were detected by screening alone. We therefore consider it is prudent for post-operative patients to remain under DR screening surveillance to detect sight-threatening disease before visual loss occurs.