Efficacy of Speech-language Pathology Therapy in Chronic Cough: Systematic Review With Meta-analysis

To analyze the efficacy of speech-language pathology therapy in the self-assessment, in the cough frequency, and the vocal quality of adults with chronic cough.

This is a systematic review with meta-analysis that answered the clinical question: "In adults with chronic cough, what is the effect of the speech-language pathology therapy in the self-assessment, in the cough frequency, and the vocal quality, compared to another intervention?" (PROSPERO 2021/CRD42021226729). An electronic search (MEDLINE, Web of Science, EMBASE, SCOPUS, Cochrane Library, and Lilacs), and a manual search (Journal of Voice, Brazilian Library of Theses and Dissertations, Open Grey and Clinical Trials) with specific search strategies was performed. The risk of bias was assessed using the Cochrane Collaboration's tool for assessing the risk of bias in randomized trials. Meta-analysis (standardized difference of means, Inverse Variance, and random effects model) and heterogeneity analysis (Chi², Tau², and I²) were performed.

We found 610 studies and selected three. There was an uncertain risk of detection bias. The data were heterogeneous, and there was no difference between interventions in self-perception of cough severity (z = 0.09, P = 0.930; tau² = 0.65, I² = 90%) and in the self-perception of the effects of chronic cough on health status (z = 0.30, P = 0.77; tau² = 0.99, I² = 97%). The estimated mean difference was 0.97 to cough frequency, and it was differ significantly from zero (z = 4.47, P < 0.001) but the results are heterogeneous (Chi² (1) = 22.22, P < 0.001, I² = 95%).

The speech-language pathology therapy had a greater effect size than the control interventions on cough frequency. However, in the subjects' perception, there were no differences between the interventions.