The effect of resistance inspiratory muscle training in the management of breathlessness in patients with thoracic malignancies: a randomised controlled trial.

PURPOSE

To assess the effects of resistance inspiratory muscle training (IMT) on breathlessness in patients with thoracic malignancies.

METHODS

This is a two-arm, non-blinded, randomised controlled trial (RCT). A total of 196 participants were randomly assigned (1:1) into two groups: a control group (routine care) and an intervention group (routine care + IMT training using a pressure threshold device). The intervention duration was 12 weeks with 30 min/day, 5 days/week. The primary outcome was breathlessness severity, assessed by the modified Borg scale (mBorg). Secondary outcomes were worst and average breathlessness over the past 24 h (assessed by the 11-point Numerical Rating Scale), breathlessness severity (assessed by the Dyspnoea-12, D-12), the 6-min walk distance (assessed by the 6-min walk test, 6MWT), quality of life (assessed by the St George's Respiratory Questionnaire, SGRQ), and emotional status (assessed by the Hospital Anxiety and Depression Scale). Assessments were conducted at baseline (T1), week 8 (T2), and week 12 (T3). Adjusted generalized estimating equations (GEE) models for repeated measures over time were performed using the Statistical Package for Social Science (SPSS) software. The modified intention-to-treat principle was used for data analysis.

RESULTS

Of the 196 participants, 190 completed the trial, and six dropped out. 31.63% of participants completely adhered to the required sessions of IMT. In the adjusted GEE model, statistical and minimal clinically important differences were observed on the m-Borg score at week 8 (P = 0.002), while no significant group-by-time effect was observed in the mBorg. Compared with the control group and baseline, participants in the intervention group showed a significant reduction in D-12 total scores at week 8 (P = 0.005) and week 12 (P = 0.004). No significant group-by-time interaction effects were observed for worst and average breathlessness over the past 24 h, anxiety, depression, 6MWT, and SGRQ scores.

CONCLUSIONS

This study highlights the short-term benefits of IMT for reducing breathlessness among patients with thoracic malignancies. However, the long-term effects should be explained with caution due to the participants' suboptimal adherence. Future studies should explore different strategies to improve adherence and further evaluate the sustained effects of IMT over time.

TRIAL REGISTRATION

ClinicalTrials.gov NCT03834116.

DATE OF REGISTRATION

2019-02-06.