Blood glucose levels in diabetic patients undergoing hyperbaric oxygen therapy

To determine if hyperbaric oxygen (HBO2) therapy has an effect on diabetic blood glucose levels (BGL) and, if so, the extent of this effect. Also, to examine factors that exacerbate any observed effect.

This was a retrospective review of prospectively collected quality data on diabetics undergoing HBO2. Pre- and post-treatment BGL were recorded. Pre-treatment BGL ⟨120 mg/dL received glucose supplementation. Hypoglycemia was defined as BGL ⟨70 mg/dL. BGL ⟨90 mg/dL was included as an elevated hypoglycemia threshold.

77 patients representing 1,825 treatments were included for analysis. No patient had deleterious side effects or required emergency care. BGL decreased in 75.4% of treatments in this group, with a median decrease of 25 mg/dL (IQR=54 mg/dL; range of decreased 374 mg/dL to increased 240 mg/dL). A statistically significant greater percentage of treatments of patients with type 2 diabetes resulted in a decrease in BGL (1598 or 77.5%) compared to treatments of patients with type 1 diabetes (169 or 51.5%) (χ2(1, N=1767) =55.37, p⟨0.001). 1.1% of treatments had post-HBO2 serum glucose ⟨90 mg/dL, and 0.2% of treatments had post-HBO2 serum glucose ⟨70 mg/dL. The majority (70%) of patients with post-HBO2 BGL ⟨90 mg/dL were maintained on insulin alone (χ2(2, N=20) =12.4, p=0.002). Well-controlled diabetics (i.e., those with all BGLs within 50 mg/dL over all pre-HBO2 treatments) had no post-HBO2 BGL ⟨70 mg/dL or ⟨90 mg/dL.

Our results suggest that HBO2 does not cause a clinically significant decrease in diabetic patient BGL. No patient in our study had deleterious side effects or required emergency care. We found that glucose level of ⟨90 mg/dL occurred more often in those who use insulin. Hyperbaric patients who exhibit consistent BGL values may represent a group who could be managed similarly to the non-diabetic population.