Measuring cough-related quality of life and cough frequency in pulmonary TB.

Abstract

BACKGROUND: Cough is the key symptom of pulmonary TB (PTB) and is associated with transmission. No tool for measuring the subjective impact of cough in PTB has been previously validated. We sought to measure patientreported cough in PTB and investigate any relationship to objectively quantified daily cough frequency.METHODS: The validity of the Leicester Cough Questionnaire (LCQ) was assessed in sequential patients newly diagnosed with PTB at a UK hospital. Resulting LCQ scores were compared to non-cough clinical variables, and to 24-h, ambulatory, objective cough frequency measured using the Leicester Cough Monitor.RESULTS: The LCQ in 30 patients with PTB was acceptable to users and had high internal reliability (Cronbach's α = 0.93), concurrent validity (correlation with visual analogue scale for cough severity, Spearman's ρ = ???0.69) and responsiveness (substantial median increase score after 2 weeks of TB treatment: 5.1 points, IQR 1.8???9.7; P = 0.003). There was only moderate correlation between patient-reported cough and objectively-measured 24-h cough frequency in PTB (ρ = ???0.48, P = 0.008).CONCLUSION: The LCQ is valid for use in PTB, with applications that include monitoring treatment of the disease. However, there was a mismatch between objective and subjective assessment of cough, which has important implications for delayed diagnosis and transmissibility.