Abstract
Purpose: :
To assess retinal central subfield thickness (CST) and risk factors for retinal edema in patients with ≥50 years of type 1 diabetes mellitus (DM) (Medalists).
Methods: :
Cross sectional evaluation of Medalists included CST (Stratus OCT), ETDRS-protocol visual acuity (VA) & fundus photography, evaluation of complications, HbA1c, lipids, islet cell antibodies, advanced glycation endproducts (AGEs) and c-peptide. Photos were graded by 2 masked readers and discrepancies adjudicated by a third.
Results: :
In 351 Medalists, mean age was 67.5+7.5 [range: 51, 89] y, DM duration 56.5+5.7 [50, 80] y, current HbA1c 7.3+1.0 [5.0, 14.0] % and 53.2% were female. Mean CST was 226.1+62.1[119, 837] µ. CST was ≥250µ in 20.5% of eyes. In Medalists with no-mild DR, zone thicknesses were comparable to previously reported diabetic subjects with mean DM duration of <15 years and no-mild DR. CST ≥250µ was associated with increased median age (73 vs 66 y, p<0.001), DM duration (58 vs 54 y, p<0.001), age at DM onset (13 vs 10 y, p=0.006), height (1.70 vs 1.65 m, p=0.006), and the AGEs CEL (7.0 vs 6.4 µmol/molLys, p=0.01) and pentosidine (1.40 vs 0.95 pmol/mg protein, p=0.002). CST ≥250µ was also associated with male gender (61 vs 42%, p=0.007), PDR (66 vs 41%, p=0.003), nephropathy (21 vs 11%, p=0.03), neuropathy (79 vs 53%, p<0.001) and cardiac disease (62 vs 45%, p=0.02). Thinner CST was modestly correlated with better vision (r=0.22, p<0.001). VA ≥20/20 was present in 42% of eyes with CST <250µ vs 24% of eyes with CST ≥250µ. No relationship was found between CST and HbA1c, lipids, islet cell antibodies or c peptide. Neuropathy (p<0.05), higher pentosidine (p=0.04) and height (p=0.01) were related to CST after adjustment for age, DM duration, age of DM onset, gender, DR severity and HbA1c.
Conclusions: :
CST in Medalists is comparable to that of patients with shorter duration DM. Although CST and VA are related, wide variability suggests that visual and anatomic outcomes may be affected by different factors. In addition, CST was correlated with pentosidine as well as the presence of other microvascular abnormalities, thus supporting further evaluation of AGEs as potential surrogate biomarkers of retinal edema and CST as a biomarker of systemic diabetic vascular complications.