# Immune-related type 1 diabetes and diabetic ketoacidosis from checkpoint inhibitors

Source: https://onco.cc/protocols/irae-diabetes/  
OnCo record `irae-diabetes` (Protocol). Data CC BY-NC 4.0, attribute "Data from OnCo (onco.cc)"; commercial use needs a licence.

## TL;DR

Rarely, immunotherapy destroys the cells that make insulin. Blood sugar can rise within days and become dangerous (diabetic ketoacidosis). Thirst, passing a lot of urine, being sick or feeling drowsy need urgent help. It is treated with insulin, which is almost always lifelong, and not with steroids.

## Summary

Rare (about 1%; 0.2 to 1.4% in the SITC 2025 definitions) but frequently serious: diabetic ketoacidosis is present at diagnosis in up to 70% (ESE 2022). Most cases follow PD-1 or PD-L1 inhibitors (76% and 8% in the series ESE cites, against 4% for CTLA-4 inhibitors); onset ranges from soon after the first dose to a year later (median 2 to 4.8 months). Autoantibodies (mostly GAD65) are found in 40 to 53%. SGLT2 inhibitors add to the risk of ketoacidosis (ESE).

Glucose is checked before every infusion and HbA1c at the start (SITC 2025 definitions). New or worsening hyperglycaemia above 11.1 mmol/L (200 mg/dL), especially without diabetes or new steroids, raises suspicion; urine ketones and blood pH screen for ketoacidosis. Ketoacidosis is treated in hospital with intravenous insulin and fluids under the usual protocols, and the checkpoint inhibitor is held until it resolves. Insulin is started urgently once the diagnosis is suspected; high-dose steroids do not help (ESE, +000). C-peptide and islet autoantibodies support the diagnosis but a normal C-peptide early on does not exclude it. Treatment is a multiple-injection insulin regimen with endocrinology referral and education; recovery is rare.

## Fields

- Kind: Protocol
- Last checked: 2026-11-11
- Also known as: checkpoint inhibitor diabetes; ICI-induced diabetes; ir-T1DM; CPI-DM; CIADM; immunotherapy diabetes; checkpoint inhibitor DKA
- Tags: protocol; irae; endocrine; acute-oncology

## Connected records

- protocols: [Baseline tests and monitoring before and during checkpoint inhibitor treatment](https://onco.cc/protocols/checkpoint-inhibitor-baseline-and-monitoring/), [Checkpoint inhibitor hypophysitis and adrenal insufficiency: emergency treatment, replacement and steroid emergency card](https://onco.cc/protocols/irae-hypophysitis-adrenal/), [Thyroid inflammation and underactive thyroid from checkpoint inhibitors](https://onco.cc/protocols/irae-thyroid/)
- technologies: [Immune checkpoint inhibitors](https://onco.cc/technologies/checkpoint-inhibitor/)
- drugs: [Atezolizumab](https://onco.cc/drugs/atezolizumab/), [Avelumab](https://onco.cc/drugs/avelumab/), [Cemiplimab](https://onco.cc/drugs/cemiplimab/), [Dostarlimab](https://onco.cc/drugs/dostarlimab/), [Durvalumab](https://onco.cc/drugs/durvalumab/), [Ipilimumab](https://onco.cc/drugs/ipilimumab/), [Nivolumab](https://onco.cc/drugs/nivolumab/), [Pembrolizumab](https://onco.cc/drugs/pembrolizumab/), [Tremelimumab](https://onco.cc/drugs/tremelimumab/)
- institutions: [American Society of Clinical Oncology (ASCO)](https://onco.cc/institutions/asco/), [European Society for Medical Oncology (ESMO)](https://onco.cc/institutions/esmo/), [Society for Immunotherapy of Cancer](https://onco.cc/institutions/sitc/)
- terms: [Immune-related adverse events (irAEs)](https://onco.cc/terms/irae/), [Immune-related endocrinopathies (thyroiditis, hypophysitis)](https://onco.cc/terms/immune-endocrinopathy/)
- key papers: [ASCO 2021 guideline: how to recognise and manage the immune-related side effects of checkpoint inhibitors](https://onco.cc/key-papers/paper-asco-irae-guideline-jco-2021/)

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