Introduction Refractory chronic cough has a significant negative impact on HRQoL. There are currently limited effective antitussive therapies. Few studies have explored the effectiveness of nonpharmacological interventions for refractory chronic cough. This study investigated the efficacy of PSALTI on HRQoL for people with refractory chronic cough in a multi-centred RCT.
Methods Participants were recruited across five NHS hospitals trusts. 76 participants were randomised to PSALTI or placebo (equal attention) intervention. PSALTI consisted of education, laryngeal hygiene and hydration advice, cough control techniques and psycho-educational counselling. Placebo consisted of general education on exercise, diet, stress and relaxation. Both groups attended 4 weekly sessions of 1:1 therapy. HRQoL was measured at baseline, four weeks (end of treatment) and 3 month follow up by Leicester cough questionnaire (LCQ). Cough reflex sensitivity was assessed at baseline and four weeks by capsaicin cough challenge (C2, C5, concentration that caused first urge to cough (Cu)) and was analysed by geometric means (GM). Outcomes between groups were analysed using ANCOVA.
Results The PSALTI (n = 35) and Placebo groups (n = 41) were well matched (p > 0.05) for age [mean (SD)] 58(15) vs. 56(11) years; gender 71% vs 63% females; cough duration [median (IQR)] 60(30 to 126) vs 48(24 to 126) months and baseline LCQ [mean (SD)] 10.4(3.6) vs 11.9(3.5). At four weeks HRQoL improved in both groups, mean LCQ increase in PSALTI was 3.4 (95% CI 2.26 to 4.55) vs placebo 1.7 (95% CI 0.78 to 2.54); difference in LCQ change between groups was 1.5 (95% CI 0.27 to 7.31, p = 0.02) points more on average in the PSALTI group. This effect is greater than the MCID for LCQ and was sustained at 3 months (mean difference change between groups after 4 weeks to 3 months was -0.28 (95% CI -1.83 to 1.38). There was a significant increase in Cu in the PSALTI group compared to placebo (GM(SD) change 2 µm (5.07) vs 0.612 µm (3.26), p = 0.02). There was no significant difference in cough reflex sensitivity between the groups (C2, p = 0.46; C5, p = 0.74).
Conclusions PSALTI significantly improved HRQoL compared with equal attention placebo intervention and this improvement was sustained at three months. PSALTI also significantly increased Cu compared to placebo.