People with type 2 diabetes mellitus (T2DM) often suffer ophthalmic complications including retinopathy, cataracts and glaucoma. This study aimed to determine longitudinal predictors of VA loss in a large community-based sample with T2DM.
The Fremantle Diabetes Study Phase II (FDS2) recruited 906 participants with T2DM who attended three biennial comprehensive clinical assessments between 2008 and 2015. Those with poor vision or blindness (VA >6/19 as per World Health Organisation guidelines) at baseline (n=10) and whose VA improved during follow-up (n=17) were excluded, leaving 874 participants. VA was tested using an ETDRS chart under standard conditions and the best-corrected eye was used to determine VA loss (a difference >10 letters) by Year 4 (3rd assessment). Forward conditional multiple logistic regression was performed to determine which baseline variables predicted VA loss.
The mean±SD age of participants was 65.0±10.5 years at entry, 54.2% were male, the median [inter-quartile range] diabetes duration was 7.0 [2.0-15.0] years and the time between assessments for those included was 4.1 [4.0-4.4] years. 27 participants (3.1%) had vision loss. Significant independent associates of VA loss were age, socio-economic indices, smoking status, blood glucose-lowering treatment, albuminuria and major depression. The major determinants of vision loss from baseline were not significantly associated with diabetic eye disorders. Older age, current smoking status and major depression had high odds of VA loss (Table).
Health professionals should be aware that smokers with T2DM are at higher risk of VA loss. As smoking is known to contribute to chronic complications of diabetes, current smokers should be encouraged to quit. Major depression may result in poor self-care, a possible explanation for the higher risk of deteriorating VA and which may be amenable to antidepressant treatment.