Exploratory randomized pilot study of written diaphragmatic breathing instructions vs. a biofeedback device for upper abdominal pain.

Objectives: Conventional therapies for chronic upper abdominal pain are often ineffective. The objective of this exploratory pilot study was to investigate the effect of brief daily breathing exercises on pain severity. Methods: Adults were randomized to written diaphragmatic breathing instructions (WIDB) or a respiratory biofeedback device (Calmigo). Participants performed 3-min exercises thrice daily for 6 weeks. Pain severity (0-4 scale) was assessed weekly. Results: 85 participants were randomized (WIDB n=36, Calmigo n=49). Linear mixed models showed significant pain reduction over time in both groups (β=-0.42 to -0.87, p<0.05), with no significant difference between groups (p=0.498). Exploratory analyses indicated that greater baseline pain (OR 2.49) predicted a higher likelihood of response, whereas White race (OR 0.40), diabetes (OR 0.48), and higher depression severity (OR 0.85) predicted a lower likelihood of response. No serious adverse events occurred. Conclusions: Brief daily breathing exercises, whether device-guided or self-guided, significantly improved upper abdominal pain. While no difference was detected between approaches, higher baseline severity predicted better response. Larger studies are needed to confirm these findings.