Effect of Inspiratory Muscle Training on Symptom Severity and Quality of Life in Non-Erosive Reflux Disease

Effect of Inspiratory Muscle Training on Clinical Symptom Severity and Quality of Life in Patients With Non-erosive Reflux Disease: A Randomized Controlled Trial

The goal of this clinical trial is to learn if inspiratory muscle training (IMT) works to treat on clinical symptom severity and quality of life in patients with Non-erosive reflux disease (NERD). The main questions it aims to answer are:

Does drug IMT lower the clinical symptom severity ? Does drug IMT improve quality of life? Researchers will compare high intensity IMT to a sham-IMT (a IMT device with no resistance) to see if IMT lower the clinical symptom severity and improve improve quality of life.

Participants will perform the following protocol:

The IMT protocol will consist of home-based high-intensity training using a Threshold IMT device: two sets of 30 breaths with a 1-minute rest, twice daily for 4 weeks. The study group will train at 60% of baseline maximum inspiratory pressure (MIP), with weekly adjustments based on modified Borg scores (4-6), while the control group will perform sham IMT without resistance.

The IMT protocol consisted of home-based high-intensity daily training - two cycles of 30 breaths with a 1-minute rest between sets, twice a day for 4 weeks using an IMT Threshold device (Threshold IMT Philips® Respironics, Inc). The IMT was performed twice a day, 7 days/week, for 4 weeks. The study group performed IMT at 60% of their baseline MIP and was adjusted weekly based on the modified Borg scale from 4 to 6 regarding respiratory effort performed during the session, while the control group performed a sham-IMT without applied resistance. Patients are evaluated before the inspiratory muscle training and after 4 weeks of training.

Inclusion Criteria:

• A clinical diagnosis of NERD,
• No erosive lesions on endoscopy,
• Presence of reflux symptoms for at least 3 months.

Exclusion Criteria:

• Current use of proton pump inhibitors (PPIs) or failure to complete a minimum 2-week washout period before enrollment.
• With known gastroduodenal ulcers
• Diagnosed with erosive esophagitis
• With hiatal hernia
• With a history of gastrointestinal malignancy
• With infectious or inflammatory gastrointestinal diseases
• With malabsorption syndrome or gastrointestinal obstruction
• With a history of major gastrointestinal surgery (including anti-reflux, gastric, or duodenal surgery)
• With systemic sclerosis or other systemic connective tissue diseases
• With severe cardiovascular, pulmonary, renal, or hepatic disease
• With chronic respiratory diseases such as asthma or COPD
• Having had an acute respiratory tract infection within the past 4 weeks
• With neuromuscular diseases
• With active tuberculosis
• Pregnancy