AI in MedTech #1: IDx-DR retinal software for early screening of diabetic retinopathy

A case study to illustrate benefit-risk assessment for an innovative AI-based screening device for early detection of diabetic retinopathy.

Living with diabetes is not easy. Not only do you have have to watch your blood sugar levels on a daily basis to avoid a life-threatening situation, you also have to worry about long term effects such as heart disease, kidney failure, or vision loss.

As an example, consider the long-term risk of losing your vision due to diabetic retinopathy. Diabetes causes damage to the blood vessels all over the body, including the retina. Retinal damage may lead to other complications such as diabetic macular edema (DME), retinal detachment and glaucoma which can cause blindness if not treated. There were an estimated 9.6 million people in the United States living with diabetic retinopathy, of which an estimated 1.84 million had a vision threatening condition¹.

The good news is that diabetic retinopathy progresses slowly and it can be treated if detected early. Bad news is that you need to visit an eye care specialist for a confirmed diagnosis.

What if a software-based solutions could help screen for early signs of diabetic retinopathy as part of the routine checkup without the need for a specialized diagnostic equipment? It could provide early warning to patients most at risk, and refer them to a specialist for diagnosis and treatment.

The IDX-DR retinal diagnostic software² does exactly that. It uses artificial intelligence (AI) to analyze retinal images of sufficient quality obtained from a commonly used retinal camera called the Topcon NW400³. This software device was granted the Breakthrough Device designation⁴ by the FDA, which fast-tracked its development and review through the De Novo reclassification process⁵, eventually leading to marketing authorization in 2018.

Health benefits of this device as part of diabetes management are clear. In the United States alone, an estimated 38.4 million people of all ages, or about 12% of the total population had diabetes in 2021⁶. Diabetes is the eighth leading cause of death in the United States, and number one cause of kidney failure, lower limb amputations and adult blindness⁷. Therefore early detection and management of long-term adverse health effects is important for the overall health and well-being of millions of people affected by diabetes.

But what about the risk(s)? Do the benefit(s) outweigh these risk(s)?

Since the FDA has already cleared this device, the answer is a definite yes! But how did the FDA come to this decision?

FDA has outlined some of the factors used to assess the benefit-risk in a 2019 Guidance Document⁸. This guidance document provides a worksheet to summarize the benefit-risk assessment using 9 questions:

Figure 1: Benefit-Risk Assessment Summary Worksheet. Source: FDA guidance

In this case study article, we will use publicly available information to reverse engineer the benefit-risk assessment worksheet for the IDX-DR device. This exercise can be useful in evaluating benefit-risk of an AI-enabled medical device for the purpose of meeting FDA expectations when preparing a regulatory submission⁹.

Let us dive in.