A study published in JAMA Ophthalmology evaluated the rates of incidence and progression of diabetic retinopathy (DR) in American Indian and Alaska Native patients.
Give me some background.
While rates of DR have declined, the prevalence of diabetes in American Indian and Alaska Native people is currently 14.7%, which is higher than other racial and ethnic groups in the US.
Prior to this study, estimates of DR incidence and progression in American Indian and Alaska Native people were based on data from before 1992, potentially making the data inaccurate.
Talk about the study.
This retrospective cohort study used de-identified medical record data obtained during routine clinical operations from the Indian Health Service (IHS) teleophthalmology program at 75 primary care clinics across 20 U.S. states. The IHS serves enrolled members of federally recognized tribes.
Tell me about the cohort.
Investigators reviewed the data from 8,374 American Indian and Alaska Native patients seen between 2015 and 2019. Within the cohort, in 2015, the mean age was 53.2 years (standard deviation [SD] 12.2 years), 57% of participants were female, and the mean hemoglobin A1c level was 8.3% (SD 2.2%).
Patient requirements?
To be included in the study, eligible patients had to be 20 years or older, have no evidence of DR, or have mild nonproliferative DR (NPDR) during the baseline period.
Patients with severe NPDR or any level of diabetic macular edema (DME) were excluded from the study.
Results?
The study found that of the patients with no DR in 2015, 18% (1,280 of 7,097) had mild NPDR or worse from 2016 to 2019, and 0.1% (10 of 7,097) had proliferative DR (PDR). The incident rate from no DR to any DR was 69.6 cases per 1,000 person-years at risk.
A total of 6.2% (441 of 7,097) participants progressed from no DR to moderate NPDR or worse, meaning a 2+ step increase, with an incident rate of 24 cases per 1,000 person-years at risk.
Anything else?
Of patients with mild NPDR in 2015, 27.2% (347 of 1,277) progressed to moderate NPDR or worse from 2016 to 2019, and 2.3% (30 of 1,277) progressed to severe NPDR or worse (i.e., 2+ step progression).
An association was observed between the incidence and progression of DR and the expected risk factors and evaluation with ultra-widefield imaging.
Significance?
Compared to the data recorded in 1992, according to the study authors, these results point to the “viability of safely extending the follow-up interval for retinopathy assessment in IHS patients who have no evidence of DR or mild NPDR.”