Association Between Prior NRICM101 Use and Response to Incentive Spirometer Training in Patients with Long COVID

Background: Inspiratory training using an incentive spirometer (IS) improves respiratory symptoms and functional status in Long COVID. In Taiwan, NRICM101 is commonly used during the acute phase; however, its impact on rehabilitation outcomes remains unclear. Objective: This study evaluated the effects of IS-based respiratory training and the potential influence of prior NRICM101 use. Methods: Participants were grouped by time since recovery, and pre-post changes after six weeks of IS training were compared between those with and without self-reported prior NRICM101 use. Primary outcomes were dyspnea and functional status; secondary outcomes included six-minute walk distance and arterial oxygen content. Results: IS training significantly improved dyspnea (p < 0.0001), functional status (p < 0.0001), and exercise endurance (NRICM101 group: p = 0.002; no NRICM101 group: p < 0.0001). Stratified analysis showed that when initiated within three months of recovery, participants without prior NRICM101 use had greater improvements in dyspnea (p < 0.0001), functional status (p = 0.001), and exercise endurance (p < 0.0001). Conclusions: Prior NRICM101 use may be associated with different rehabilitation patterns, likely reflecting differences in recovery trajectory or patient behavior rather than purely pharmacological effects.