The clinical usefulness of a self-administered questionnaire for sleep-disordered breathing in patients with neuromuscular disease

Background: Patients with neuromuscular disease (NMD) are at risk of developing sleep-disordered breathing (SDB) with hypercapnic respiratory failure. We hypothesised that a self-administered questionnaire (SiNQ-5 scores) may be useful to assess patients who are established on treatment for NMD with SDB. Methods: Patients attending a tertiary referral centre filled in the SiNQ-5 (range 0-10 points, lower scores indicating fewer symptoms). The questionnaire contains five questions related to breathlessness, sleep and posture. Patients with NMD and treated SDB were compared to NMD without SDB, to sleep apnoea, chronic obstructive pulmonary disease (COPD) and heart failure (HF) patients' scores, as well as a group of patients without SDB. Results were compared using Kruskal-Wallis one-way analysis of variance, with Dunn/Bonferroni post-hoc tests if comparisons were found to be statistically significant. Results: A total of 265 (156 male) patients completed the assessment, 40 had NMD with treated SDB [SiNQ-5 score 3.4 (3.0) points], 11 had NMD without SDB [2.7 (2.9) points], 120 patients had obstructive sleep apnoea (OSA) [4.1 (2.6) points], 16 had COPD [3.9 (3.0) points] and 9 had HF [3.2 (2.8) points], 69 patients had other conditions with no evidence of SDB [3.0 (2.4) points; P=0.077]. Patients with NMD without SDB and those with SDB who were on treatment did not differ in their responses (P=0.417). Question #1 allowed discrimination between patients with NMD with SDB [0.8 (0.8) points] and other disorders without respiratory involvement [0.3 (0.6) points; P=0.024]. Conclusions: The SiNQ-5 scores in neuromuscular patients with SDB who are established on treatment and NMD patients without SDB, as well as in patients with other conditions leading to SDB are similar.