Predictors of treatment response to pregabalin in unexplained or refractory chronic cough

Abstract

BackgroundPatients with chronic cough (>8 weeks) often remain symptomatic after appropriate investigations and therapeutic trials. Prior research has shown a benefit in certain individuals from pregabalin, but clinical improvement is quite unpredictable and variable. ObjectiveThe main objective of this study was to identify the demographic and clinical characteristics associated with a higher likelihood of cough improvement with a trial of pregabalin therapy. Methods50 consecutive patients with chronic cough were enrolled in this prospective cohort study. Subjects were prescribed pregabalin 75 mg oral qhs for 4 weeks followed by 75 mg oral bid. Leicester Cough Questionnaire (LCQ) was completed at treatment initiation and after 3 months of therapy. A comparison was performed between treatment responders (LCQ total score improvement ≥1.3) and non-responders. Results56% of patients reported a LCQ total score improvement ≥1.3 (minimal clinically important difference). Responders to pregabalin therapy were more likely to have refractory (with underlying pulmonary disease) versus unexplained chronic cough (p = 0.01). Patients with significant improvement were also on average more symptomatic at baseline (mean LCQ total score 10.2 versus 13.0, p < 0.01). No significant relationship was identified with age, gender, body mass index, history of anxiety and/or depression, cigarette smoking history, or cough duration (p > 0.05). The unexplained chronic cough group had a strong female predominance (85.7% versus 40.9% for refractory cough, p < 0.01). ConclusionThis is the first study that has investigated clinical predictors of treatment response to pregabalin in chronic cough patients. Further research is needed to develop therapies for subjects who do not improve with currently available neuromodulating medications.