A Year on the Best Available Technology, and Two Events It Didn't Stop
He's already tried the most advanced non-surgical option there is. The disagreement isn't whether transplant could help him eventually — it's whether one real year on one specific system counts as having exhausted the alternative.
Kyle B., a 34-year-old man, climbs telecommunications towers for a living, often working alone for stretches of an hour or more several hundred feet up, a job he's held for nine years and one he says he'd genuinely miss if he ever had to give it up. He has had type 1 diabetes since age nine, and over the past two years has developed clear hypoglycemia unawareness — three emergency department visits and two glucagon rescues administered by coworkers in the past eighteen months, several without the warning symptoms he used to reliably feel before a low. He started a current-generation hybrid closed-loop automated insulin delivery system a year ago, optimized carefully with his diabetes team over that time, and while his overall glycemic control has genuinely improved, he has still had two severe hypoglycemic events on the system, most recently three weeks ago.
That detail is what makes today's conversation different from a routine device check-in: a full year on the most advanced commercially available closed-loop system, carefully optimized, with continued severe events, raises the real question of whether his ceiling on device therapy alone has already been reached. Islet transplantation exists specifically for patients like this — refractory hypoglycemia unawareness despite optimized conventional therapy — and registry outcomes in appropriately selected patients show substantial reduction in severe events, sometimes restoring real hypoglycemia awareness. But it isn't a free option: it commits a 34-year-old to lifelong immunosuppression, with its own cumulative infection and malignancy risk over what could be another five decades of his life, and graft function is not guaranteed to last indefinitely.
A year of real optimization, and two events it didn't stop
I'd refer him for islet transplantation evaluation now. He's had a genuine, carefully optimized twelve-month trial on the most advanced closed-loop system commercially available, and he's still had two severe events on it. That's not a device that hasn't been given a fair chance — it's a real ceiling, and the Collaborative Islet Transplant Registry’s data in exactly this population show islet transplant meaningfully reducing severe events, sometimes restoring awareness altogether.
I'd hold off on referral, and I say that as the one who'd actually be doing the transplant. A year on one specific system is real progress, but it isn't the same as having exhausted device optimization broadly — algorithm updates, adjusted targets, and newer sensor technology are still evolving quickly in this space. He's 34. Committing him to lifelong immunosuppression now means decades of accumulating infection and malignancy risk, and graft function isn't guaranteed to last that whole time either.
I'm not arguing transplant is never right for him — I'm arguing two severe events in a year, on his first extended run with this specific technology, isn't yet the same as "device therapy has reached its ceiling." I'd want to see a genuinely optimized second attempt before recommending a decision this permanent.
I don't think either of you is wrong about the general timeline — I think his specific circumstances should move the clock forward regardless of where that general timeline usually sits. He works alone, often at real height, and lives alone. An unrecognized severe hypoglycemic event in that setting isn't a bad afternoon, it's a fall risk with no one immediately there to help.
That doesn't automatically mean transplant today. It means the further- optimization window the transplant physician wants should be short and concrete — a defined few months, with a specific new intervention actually tried, not an open-ended "let's keep watching" — given what a missed warning sign could cost him at work.
AID settings reoptimized with a new target profile, a bounded three-month re-evaluation scheduled, and islet transplant evaluation initiated in parallel so no time is lost either way. Kyle's employer was engaged, with his consent, to review protocol adjustments for solo work at height during the interim.
Not agreed: what specifically would count as the reoptimized trial "failing" at three months — any further severe event at all, or a defined frequency threshold. The endocrinologist wanted a zero-tolerance bar given the stakes; the transplant physician argued a single isolated event shouldn't automatically trigger listing given normal biological variability. Left for the three-month visit to define more precisely once real data exists to define it against.