Abstract
BACKGROUND: Diabetes mellitus (DM) is a severe, chronic and complex metabolic disease that leads to multiple dysfunctions, including micro and macrovascular complications, which are a major cause of morbidity and mortality. Type 2 DM (T2D) is highly preventable, and the stages that precede it are the ideal target for therapeutic intervention. Hyperbaric oxygen therapy (HBOT) is an established medical treatment for several clinical conditions. Because DM is one of the most prevalent comorbidities in patients under HBOT, it has allowed the observation and inference of some of its effects on DM, suggesting clinical benefit in different spectrums of the disease. Our main aim was to gather the existing evidence on the impact of HBOT on insulin resistance, as this is the best predictor for the development of T2D. MATERIALS AND METHODS: The scoping review was the methodology chosen to include all available data. Exclusion criteria consisted of articles that did not mention the effects of HBOT on insulin resistance, described only the use of normobaric oxygen, or had no available translation to English, Spanish, or Portuguese. In addition, all data discussing any effects on insulin, insulin resistance, or insulin sensitivity were included. RESULTS: Two hundred and thirty studies were found, and 17 were eligible. The HBOT appears to improve fasting glycaemia and decrease insulin resistance in patients with DM, with effects appearing after 1 treatment session. Additionally, it reduces levels of proinflammatory cytokines that contribute to insulin resistance. The duration of this sensitisation effect remains unknown, as do the contributing molecular factors. CONCLUSION: HBOT seems to improve glycaemic levels and insulin sensitivity, thus presenting a potential treatment approach to treat insulin resistance and its consequences. However, translation into clinical practice remains contingent on robust, yet unavailable, randomized clinical trials.