Approximately 20% of adolescents with type 1 diabetes mellitus living in the US, Australia, France, and the UK between 2010 and -2019 were found to have diabetic retinopathy (DR), according to research published in Diabetes Care. That number is down from approximately 40% in the years between 1990 and 1999, but consistent with the recorded prevalence between 2000 and 2009. The study demonstrates the effect of contemporary guidelines for lower glycemic targets, and especially increased applications of continuous subcutaneous insulin infusion (CSII), according to the researchers.
Researchers examined 2404 participants (aged 12-20 years, 52.7% girls and women) who have had diabetes for more than 5 years. The investigators divided the participants into 3 groups according to when they presented (1990–1999, 2000–2009, 2010–2019). They reviewed patients’ retinal images (which were captured and graded to assess for DR) along with stereoscopic retinal photographs (to determine if diabetic macular edema [DME] was present). Patient demographic information (race, sex, socioeconomic status [SES]), cholesterol, body mass index (BMI), and blood glycemic level were noted. The investigators also recorded the number of insulin injections per day, use of CSII, and total insulin dose per kilogram per day.
The team analyzed a total of 5487 complications assessments. In the 1990-1999 group, with the use of CSII at 0%, DR prevalence was 40%. In the 2000-2009 group (when CSII use had climbed to 12%) DR prevalence was down to 21%. Although the third group had a CSII rate of 55%, their DR prevalence was 20%.
Blood glycemic levels were relatively unchanged throughout each decade (8.7%, 8.5%, and 8.7%, respectively; P <.001) and no significant changes in proportion of participants meeting glycemic control goals was found.
The researchers note that while the proportion of individuals remained stable in all 3 groups, the prevalence of obesity increased with each decade (5.3%, 10.5%, and 11.7%, respectively, P <.001). A complication of DR is more common among older age groups, with this study showing that 12.8% of participants aged 12 to younger than 14 years developed DR, while it was detected in 24.1% of participants aged 14 to younger than 16 years, 26.2% of participants aged 16 to younger than 18 years, and 34.5% aged 18 to 20 years.
The analysis shows that DME development is associated with receiving 1 to 2 daily injections (vs multiple daily injections or CSII), longer diabetes duration, higher diastolic blood pressure SDS, higher HbA1c, and elevated cholesterol. The study shows no significant time trend in DME and low prevalence across all 3 decades (1.4%, 0.5%, 0.9%, respectively, P =.13). Of the 43 complication assessments (34 individuals) where DME was discovered, it was concurrent with DR in 40 instances (93%). Most of those cases (20 individuals) were in the 1990-1999 group (with 6 in the 2000-2009 group, and 8 in the 2010-2019 group). Patients with DME had a mean diabetes duration of 10.5±3.4 years (P <.01) and higher HbA1c than those without DME (P <.01).
The results confirm previous research that has shown an association between intensive treatment (with multiple daily injections or CSII) and a decrease in the prevalence of DR. Researchers note their finding of overweight/obesity as a risk factor for DR, which has not been previously identified in the literature.
“In our cohort, both severe NPDR and PDR occurred prior to 18 years of age, albeit uncommonly. CSII is associated with a lower prevalence of DR, and we theorize that reduced glycemic variability in CSII users underpinned this risk reduction, given the largely unchanged HbA1c levels across 30 years of follow up,” according to the researchers. “HbA1c, cholesterol, overweight/obesity, and DBP remain modifiable risk factors for DR and DME. Despite intensified therapy, HbA1c has remained relatively level and well above suggested thresholds for adolescents with type 1 diabetes.”
A limitation of this study is the use of a tertiary care center (CHW), which researchers expected to create bias due to the higher level of care provided. However, DR was more prevalent compared to other studies conducted in similar tertiary care centers, suggesting this region is at a higher risk for DR and preventing the generalizability of these results.
Allen DW, Liew G, Cho YH, et al. Thirty-year time trends in diabetic retinopathy and macular edema in youth with type 1 diabetes. Diabetes Care. Published online May 20, 2022. doi:10.2337/DC21-1652