Sci Rep. 2025 Aug 4;15(1):28351. doi: 10.1038/s41598-025-11539-0.ABSTRACTA potential beneficial effect of hyperbaric oxygen therapy (HBOT) on complaints of long COVID was found, leading to increased demand for this treatment despite many remaining clinical questions and lack of formal guideline recommendations and reimbursement. A registry was set up in order to gain more insight into patient characteristics and (long-term) outcomes of long COVID patients undergoing HBOT. Patient-reported outcome measures were collected at baseline, after treatment, at 3-month and 1-year follow up. This publication includes the 3-month results. The primary outcome measures were the mental and physical component score (MCS/PCS) of the SF-36 questionnaire. A clinically relevant positive or negative response was defined as a ≥ 10 point increase or decrease of in MCS and/or PCS after 3 months. Secondary outcomes included the EQ-5D, severity of complaints and ability to work. In this prospective registry, 56-63% of long term-ill patients had a clinically relevant improvement in MCS/PCS 3 months after HBOT. However, 13-19% of the patients had a clinically relevant deterioration in MCS/PCS. Symptoms that showed most improvement were predominantly in the cognitive domain. This indicates that HBOT may have a positive effect on complaints of long COVID, but alertness for worsening of the condition should be exercised.PMID:40759992 | DOI:10.1038/s41598-025-11539-0