Diabetic Retinopathy: prevalence and associated risk factors amongst patients diagnosed with diabetes mellitus

Non-communicable diseases (NCDs) such as cardiovascular disease, cancer, respiratory disease, and diabetes are becoming more prevalent worldwide, particularly among people aged 30–69. Each year, these diseases take a toll on around 41 million people globally.1 Of these, diabetes is responsible for killing around 6.7 million people in 2021, making it a major public health concern.

Moreover, the number of people suffering from diabetes is estimated to rise to 643 million by 2030 and 783 million by 2045, especially in low and middle-income countries. Diabetes-related healthcare spending has risen to USD 966 billion in 2021.2 Yet diabetes complications such as ischemic heart disease, nephropathy, neuropathy, and retinopathy are widespread.3 Furthermore, despite the availability of appropriate diagnostic and treatment options, it is suspected that about one in every two people living with diabetes is undiagnosed.2

In the following blog, we will evaluate the prevalence and risk factors for diabetic retinopathy in diabetes patients by analyzing the findings of three different research studies.

To begin with, how prevalent are these ocular complications?

Diabetes-related eye complications such as diabetic retinopathy (DR), diabetic macular edema (DME), cataracts, and glaucoma affect roughly one-third of diabetes patients worldwide.4 In the United States alone, 4.1 million adults aged 40 and above have advanced, vision-threatening retinopathies.5 What is the reason behind this? Let us examine some case studies to identify the risk factors that may lead to ocular complications in diabetes patients.

A link between long-term uncontrolled diabetes and eye tissue damage!

The first research study examined 1232 patients diagnosed with diabetes within the last 0–5 years to collect relevant data. Following analysis, it was discovered that the study population’s age- adjusted and sex-adjusted prevalence of DR and DME was 17.4% and 6.6%, respectively. Also, the ODDS ratio (a measure of association) for high levels of HbA1c was found to be 2.98 and 2.38 for DR and DME, respectively. While for albuminuria, the ratio was 2.45 for both diseases.

Furthermore, their prevalence increased as the duration of diabetes increased. Thus, it can be inferred that long-term uncontrolled diabetes and albuminuria increase the risk of eye complications in diabetic patients. The study findings are summarized in figures 1 and 2.6

Figure 1: The odds ratio of risk factors for eye complications (DR and DME) in diabetic patients
Figure 2: The prevalence of ocular complications w.r.t. duration of diabetes

Is the risk of eye complications higher in elderly diabetes patients?

To answer this question, a study was conducted on 4,251 people with type 2 diabetes to know the prevalence of ocular complications in the elderly. The results of this study showed that DR was prevalent in 30.7%, whereas vision-threatening DR was found in only 7% of the study population. Moreover, high diastolic blood pressure, along with long-term uncontrolled diabetes and higher postprandial serum glucose, was found to increase the risk of developing vision-threatening eye complications in the elderly. The study findings are depicted in Figure 3.7

In fact, when a total of 300 adult patients (age>18 years) with equal numbers of males and females were examined for diabetic retinopathy, its findings were found to coincide with the previous study.8

Figure 3: Graph showing the p-value association of risk factors with development of DR.

How can we interpret these studies?

It is clear from the above discussion that age, duration of diabetes, hypertension, uncontrolled blood glucose levels, albuminuria, and high cholesterol levels can increase the risk of DR and DME, especially in the elderly. Long-term hyperglycemia not only damages body tissues but also slows recovery in affected patients. Hence, efforts must be made to control hyperglycemia. Moreover, regular physical check-ups in diabetes patients can help in the early detection of these complications.

What can be the possible solutions?

Since early detection of diabetic retinopathies can help prevent vision loss in diabetic patients, they should be educated on the importance of regular health checkups. Moreover, efforts are being made to develop an AI-powered diagnostic tool for the early detection of diabetic retinopathy,

such as artificial intelligence-enhanced Retinophotography9 and an automatic analysis algorithm for referable diabetic retinopathy from fundus images.10

In addition, patients should be informed about the various treatment options for DR, like laser therapy, VEGF inhibitor drugs, vitrectomy, retinal reattachment, and corticosteroid injections.11 Furthermore, drugs such as Faricimab-svoa (recently approved by the FDA)12 and Lucentis (in phase 4 clinical trial)13 offer patients new hope for DR and DME treatment.

Conclusion

It is clear from the preceding discussion that complications like diabetic retinopathy and diabetic macular edema can cause vision loss in patients with uncontrolled long-term diabetes. While efforts are being made to develop diagnostic and therapeutic solutions for early detection and treatment of DR and DME, more research is required to determine their safety and efficacy.

Meanwhile, patients should be made aware of the risks and complications of diabetes. They should also be encouraged to regulate their blood glucose and blood pressure with proper medication, frequent health checks, diet control, and exercise to decrease the risk of vision loss due to diabetic retinopathy. In the future, the breakthroughs in the development of effective diagnostic and treatment options will help reduce healthcare costs for management of diabetes-related complications while also improving clinical care quality and overall life quality for diabetic patients.

References

  1. World Health Organization. Non communicable diseases. who.int. Published on 13 April,  Accessed     on     9     August,     2021.                         https://www.who.int/news-room/fact- sheets/detail/noncommunicable-diseases
  2. International diabetes Diabetes facts and figures. idf.org. Updated on 09 December, 2021. Accessed on 9 August, 2021. https://idf.org/aboutdiabetes/what-is-diabetes/facts- figures.html#
  3. Cade WT. Diabetes-related microvascular and macrovascular diseases in the physical therapy Phys Ther. 2008;88(11):1322-1335. doi:10.2522/ptj.20080008
  4. Hashemi H, Rezvan F, Pakzad R, et Global and regional prevalence of diabetic retinopathy; a comprehensive systematic review and meta-analysis. Semin Ophthalmol. 2022;37(3):291- 306. doi:10.1080/08820538.2021.1962920
  5. Kempen JH, O’Colmain BJ, Leske MC, et al. Eye Diseases Prevalence Research. Arch Ophthalmol. 2004;122(4):552-63. doi: 10.1001/archopht.122.4.552.
  6. Graue-Hernandez EO, Rivera-De-La-Parra D, Hernandez-Jimenez S, Aguilar-Salinas CA, Kershenobich-Stalnikowitz D, Jimenez-Corona Prevalence and associated risk factors of diabetic retinopathy and macular oedema in patients recently diagnosed with type 2 diabetes. BMJ open ophthalmol. 2020;5(1):e000304. doi: 10.1136/bmjophth-2019-000304.
  1. Halim A, Syumarti S, Rini M, et Prevalence and associated factors of diabetic retinopathy in people with type 2 diabetes attending community based diabetic retinopathy screening in Greater Bandung, Indonesia. Int. J. Retin. Vitr. 2022;5(1):1-1. doi.10.35479/ijretina.2022.vol005.iss001.172.
  2. Amer J, Suboh R, Abualrob M, Shaheen A, Abu Shanab AR. Risk factors associated with diabetic retinopathy: a cross-sectional study within Palestinian patients in Northern West Front. Clin. Diabetes Healthc. 2021;2:736715. doi.10.3389/fcdhc.2021.736715
  3. gov. Screening for diabetic retinopathy in pharmacies with artificial intelligence enhanced retinophotography (DIABeyeIA). clinicaltrials.gov. Updated on 12 July, 2022. Accessed on 9 August, 2021. https://clinicaltrials.gov/ct2/show/NCT05452993
  4. gov. Validation of an automatic analysis algorithm of the referable diabetic retinopathy from fundus images. clinicaltrials.gov. Updated on 25 July, 2022. Accessed on 9 August, 2021. https://clinicaltrials.gov/ct2/show/NCT05471986
  5. Centre for disease control and prevention. Diabetes and vision loss. cdc.gov. Updated on 7 May, 2021. Accessed on 9 August, 2021. https://www.cdc.gov/diabetes/managing/diabetes- vision-loss.html
  6. Clinical trials arena. Vabysmo (faricimab-svoa) for the treatment of neovascular age-related macular degeneration and diabetic macular clinicaltrialsarena.com. Published on 25 March, 2022. Accessed on 9 August, 2021. https://www.clinicaltrialsarena.com/projects/vabysmo-faricimab-svoa-namd-dme/
  7. gov. Effects of intravitreal ranibizumab for macular edema with nonproliferative diabetic retinopathy. clinicaltrials.gov. Updated on 22 May, 2020. Accessed on 9 August, 2021. https://clinicaltrials.gov/ct2/show/NCT02834663

Author: Geetika Garg

Reviewer: Priyanka