PURPOSE: To develop a simple, brief, patient-completed tool that screens for patients at risk of airflow obstruction.
METHODS: The lung function questionnaire (LFQ) was developed in 3 phases: 1) Empirical phase: using the NHANES III; 2) Qualitative phase: questions identified in phase 1 evaluated for clarity by patients/clinicians; 3) Quantitative phase: ongoing validation study of the revised LFQ. Phase 1 questions were identified from a comprehensive literature survey of similar existing questionnaires and clinical input from physicians. Age, smoking, wheezing, cough, dyspnea, BMI, and phlegm were included in stepwise logistic regression methods to predict airflow obstruction (defined by pre-bronchodilator FEV1/FVC < 70%). Screening accuracy of LFQ was then evaluated in a population >40 years of age and diagnosed with chronic bronchitis (CB) using Receiver Operating Characteristic (ROC) analysis. In Phase 2 qualitative research with patients and physicians was conducted to evaluate clinical relevance as well as patient understanding (face and content validity). Sixteen in-depth individual patient interviews and 2 primary care physician focus groups (8 physicians each) were conducted with 16 primary care physicians.
RESULTS: Age, wheeze, dyspnea, smoking were (cough and BMI were not) predictive of airflow obstruction based on NHANES (OR: 3.32 p<0.0001; 1.6 p<0.10; 2.0 p<0.05; 1.81 p<0.05 respectively). Based on physicians’ input, “phlegm” (OR: 1.55 at p<0.10) was forced into the model due to its clinical relevance. Screening accuracy was moderate-fair (CB population) with positive predictive value of 65% (AUC=0.716, sensitivity=71%, specificity=59.3). Patients felt items and concepts in LFQ were relevant to their disease and symptoms. Smoking questions were reordered and dyspnea question was re-worded. Based on physicians’ feedback, mucus replaced “phlegm”.
CONCLUSION: The final LFQ contained age, wheeze, dyspnea, smoking and phlegm as questions being predictive of airflow obstruction. LFQ demonstrates moderate screening accuracy both in a CB population and in a general population in NHANES. A validation study is underway to further evaluate LFQ in a general population.
CLINICAL IMPLICATIONS: Use of LFQ will help identify candidates for spirometry and address undiagnosed COPD issue.
DISCLOSURE: David Mannino, Employee Anand Dalal and Priti Jhingran are currently employed by GlaxoSmithKline (GSK); Consultant fee, speaker bureau, advisory committee, etc. Mark Kosinski performed analyses using NHANES data from CDC. All other authors did not receive any funding from GSK. They served on a advisory capacity.; No Product/Research Disclosure Information