#54–Kevin Sayer, CEO of Dexcom: Continuous glucose monitors–impact of food, sleep, & stress

KEYPOINTS

• 01

  How a Dexcom sensor reads glucose

  Sayer, Dexcom's CEO, explains that a wire about as thin as a human hair, made of special alloys and coated with membranes, sits roughly half an inch under the skin in interstitial fluid. It measures glucose there, not in blood. An enzymatic reaction produces an electrochemical signal, and an algorithm in the transmitter converts it to a glucose value. Attia notes that point-of-care tests suit analytes like glucose, ketones, lactate and electrolytes, whereas insulin or lipoprotein counts need lab methods such as ELISA or NMR.

• 02

  The G6 removed the scary part

  Earlier models had users push the needle in themselves; Sayer says some patients emailed that they had stared at the device for six weeks without daring to insert it. The G6 inserts automatically, faster than a hummingbird beats its wings a couple of times. Attia saw the old applicator scare off some of his own patients after they had paid out of pocket.

• 03

  Most people with type 1 diabetes still weren't using one

  At the time of recording (2019), Sayer estimated about 1.3–2 million Americans had type 1 diabetes, plus about 1.5 million with type 2 who use insulin intensively. Only about 20–30% of people with type 1 used a CGM, though he believes 80% of that intensive-insulin population should. Medicare began covering CGM for intensive insulin users with type 2 in January 2017.

• 04

  Insurance coverage is cyclical

  Sayer describes one state that required a person with type 1 to document a number of readings below 50 mg/dL before getting coverage. He says payers often cover generously for a couple of years, then tighten criteria, and that price and access are traded off in constant negotiation.

• 05

  The biggest savings come from avoiding low-sugar hospitalizations

  Sayer's economic models show the major acute saving is preventing hospital stays in 'hypoglycemia unaware' patients. Each such stay costs $10,000–30,000 by the numbers he has seen. Dexcom's share feature, which he says the company pioneered and got through the FDA, lets a spouse in another country see a low and phone the hotel to wake the wearer.

• 06

  Performance first, then experience, then cost

  Sayer's framework for the Verily (Alphabet) partnership is performance, then patient convenience, then cost. Dexcom supplies the membranes and algorithms; Verily supplies miniaturised electronics and Bluetooth. Attia suggests average accuracy has reached diminishing returns. Sayer agrees, saying the remaining gain is 'eliminating the outliers' so every sensor behaves the same.

• 07

  Type 1 and type 2 deserve different names

  Attia argues that lowering glucose in type 2 by adding insulin, or drugs that raise the body's own insulin, reduces small-vessel complications but doesn't save lives. Patients still get heart disease, cancer and Alzheimer's at higher rates, because the problem is high glucose combined with high insulin. He points to drugs that remove glucose without adding insulin, such as metformin and SGLT2 inhibitors. Sayer says Dexcom's type 2 software focuses on daily feedback rather than nighttime alarms.

• 08

  Real-time feedback changes behaviour

  Attia believes CGM improves outcomes even without a formal intervention, simply because it's hard to ignore how food, stress and sleep move the number. He finds the 7-day average and standard deviation, and the 90-day trailing average, more useful than single readings.