A study that finds a benefit and a harm in the same foot is unusual, and the two results get described in units that make one sound large and the other small. Both are worth a few sentences each, in the form absolute numbers put them in.
The comparison
Adults with type 2 diabetes carrying a neuropathy diagnosis were identified in a US research network as they started either a GLP-1 or a DPP-4 inhibitor. [1] Matching on demographics, other conditions and medications left 19,770 in each arm, followed for one and two years, with Bonferroni correction applied to the significance threshold.
Fewer ulcers
Diabetic foot ulcers occurred in 2.2% of GLP-1 patients against 2.7% on the comparator, a hazard ratio of 0.813, 95% CI 0.716 to 0.922. All-cause mortality was lower too, though the authors explicitly label that one hypothesis-generating rather than a finding.
In absolute terms that ulcer result is half a percentage point, or five fewer people per thousand in a year. Real, and smaller than an 18.7% relative reduction sounds.
More Charcot
Charcot neuroarthropathy — the collapse of bones and joints in a foot that has lost protective sensation — occurred in 0.3% of GLP-1 patients against 0.2%, a hazard ratio of 1.993, 95% CI 1.297 to 3.064. It survived the corrected threshold.
That is roughly double, and roughly one extra case per thousand people per year. Both descriptions are accurate, and Charcot is a serious, sometimes limb-threatening problem, so the small absolute number is not a reason to skip past it.
What did not change
Amputation ran at 0.5% in both arms, hazard ratio 1.073, 95% CI 0.810 to 1.421. Foot and ankle osteomyelitis ran at 0.4% in both, hazard ratio 0.978, 95% CI 0.708 to 1.349.
So the hardest endpoints did not move in either direction. A benefit on ulcers and a signal on Charcot with no change in amputation is a picture that resists a simple headline — which is usually what a real safety signal looks like before anyone has sorted it out.
What a buyer does with it
This is a diabetes population, and most people buying a GLP-1 from a telehealth seller do not have diagnosed neuropathy. If you do, this is a conversation to have with whoever manages your feet, and it is not one a subscription form will start.
The other limit is familiar. Both arms are drug classes rather than products, so nothing here separates semaglutide from tirzepatide — the same problem as any comparison whose loser has no name, and a reminder that effects that are not about weight are where most of the open questions still sit.