The incidence of hypoglycemia during HBO2 therapy: A retrospective review

Hypoglycemia is concerning in patients with diabetes undergoing hyperbaric oxygen (HBO2) therapy. We aimed to estimate the incidence, risk factors and a pretreatment glucose threshold of HBO2-associated hypoglycemia.

We retrospectively evaluated a patient cohort undergoing HBO2 therapy. We calculated the area under the curve (AUC) and odds ratio (OR) with 95% confidence interval (CI) adjusting for patients' age, gender, diabetes type, insulin use, body mass index, hemoglobin A1c and HBO2 treatment time.

During 77 months, 3,136 HBO2 sessions were performed on patients with diabetes. In-chamber glucose was higher than pre-HBO2 glucose in 1,708/3,136 sessions (54%). The incidence of hypoglycemia (defined as ≤ 70 mg/dL) during or immediately after HBO2 treatment was 1.5% (0.8-2.1%). Hypoglycemia that was symptomatic or severe was rare. A glucose value pre-HBO2 of 150 mg/dL best predicted the risk of subsequent hypoglycemia (AUC 0.80; 95% CI, 0.75-0.86). Type 1 diabetes was independently associated with increased risk of hypoglycemia (OR 3.69; 95% CI, 1.67, 8.19) whereas insulin use was not.

In patients with diabetes undergoing HBO2, severe hypoglycemia is rare and occurs more frequently in Type 1 diabetes. Pre-HBO2 glucose values may be used to predict subsequent hypoglycemia and reduce the need for routine glucose monitoring during and after HBO2.