A study published in AJO examines how social determinants of health (SDH) impact diabetic retinopathy (DR) prevalence in the US. The research found that individuals with poor health, disabilities, public insurance, low income and less education had significantly higher odds of developing DR. Geographic location also played a role, with those living in the South twice as likely to report DR compared to those in the Northeast. Photo: Optos. Click image to enlarge.

The prevalence of diabetes is known to be associated with almost all aspects of social determinants of health (SDH), including income, education, occupation, housing, environment, food insecurity, access to healthcare and social support, according to the American Diabetes Association. Considering that 40% of Americans are predicted to develop diabetic retinopathy (DR), one of the most common complications of diabetes, it’s not surprising that DR is also associated with several areas of SDH, but few studies have examined the impact of all five domains of SDH on DR’s prevalence in a United States population-based sample. That was the goal of a new study, published in American Journal of Ophthalmology, which used self-reported data to find a significant association between DR and poorer health status, disability, no employment status and living in Southern regions of the US. 

The population-based, cross-sectional analysis used data from the 2017 National Health Interview Survey (NHIS), of which 26,699 participants answered the question, “Have you ever been told by a doctor or other health professional that you had diabetic retinopathy?” One-percent (266 respondents) self-reported a DR diagnosis. This sample included 143 male and 123 female patients. Of these, 51.1% were between the ages of 41 to 65, 38.7% were married, 36.1% had advanced degrees, 71% weren’t employed in the past 12 months and 74.3% identified as white.

In the category of healthcare access, researchers found disability, health status and insurance status all had an association with self-reported DR. Participants who identified their health as poor reported a more than 16 times higher odds of having DR compared to those who identified their health status as good. Those who reported a disability had six times higher odds of DR in comparison to those who didn’t report a disability. Those with public insurance or other healthcare coverage had a more than three and five times higher odds of DR than those with private insurance, respectively.

Economic stability had an association as well, as those who were in the one- to three-times poverty threshold or below had a two and three times higher chance of DR, respectively, than those whose income level was at least five times the poverty level. Those who delayed medical care due to cost and those who hadn’t been recently employed had a two and four times higher likelihood of DR, respectively, than their counterparts.

When looking at education and geography, researchers found that those with less than a high school degree were two times more likely to have DR than those with advanced degrees, and participants living in the South were twice as likely to have DR than those living in the Northeast.

Lastly, age, marital status and parental status were associated with self-reported DR.

Participants who were in the 41-to-65 age group and 65-plus age group had a more than six and nine times higher odds of DR, respectively, in comparison to those in the 18-to-40 age group. Participants who were divorced, separated or widowed had two times higher odds of DR than those who were married. Parents and caregivers of minors were also less likely to have DR than those who weren’t. Women were 0.6 times less likely to have DR than men.

Another aspect of this study revealed that individuals who didn’t have a regular place of healthcare had lower rates of self-reported DR. This might be explained by the fact that these participants were possibly unaware of their DR status due to lack of regular eye exams. “Without a usual place of healthcare, individuals may not have access to routine eye care or may not seek medical attention unless symptoms become severe,” the authors wrote in the journal. “This lack of proximity to an eye care provider could lead to underdiagnosis and misclassification of self-reported DR status in self-reported data.”

Geographic location emerged as a significant factor, according to the authors, who cited links between the South’s prevalence of DR with environmental issues, such as limited access to recreational facilities, sidewalked and safe areas for physical activity (which contribute to higher obesity rates), in addition to limited access to healthy foods, further exacerbating obesity rates. “The combination of these environmental factors creates a significant barrier to maintaining a healthy lifestyle, thereby increasing the risk of developing obesity-related complications such as DR,” they wrote. “Addressing these environmental disparities through urban planning, improved access to healthy foods and community-based health initiatives is crucial for mitigating the impact of obesity on DR in these regions.”

The authors do point out in the study that the self-reported data may introduce inherent biases, such as recall bias and social desirability bias. “These factors may impact the generalizability of our findings and should be considered when interpreting the results,” they wrote. “Researchers must be cautious in interpreting results and consider potential biases in their analyses and conclusions. Future studies could benefit from incorporating a combination of self-reported data and objective measures to improve the accuracy of prevalence estimates and the robustness of findings.”

Despite these limitations, the authors say this study fills a gap in the literature on how SDH impact DR. “Further research with robust methodology should be conducted to better understand the mechanisms and patterns behind social factors and chronic diseases such as diabetic retinopathy. The findings from our study can be used to initiate future research as well as inform public health policies and interventions,” concluded the authors.