Specific COPD Questionnaire Cutoff Threshold May Identify More Symptomatic Patients

doctor speaking with patient
doctor speaking with patient
The Clinical COPD Questionnaire cutoff point of 1.4 demonstrated a better agreement with other COPD measures in patients with more symptomatic disease.

The Clinical Chronic Obstructive Pulmonary Disease (COPD) Questionnaire (CCQ) demonstrated significant clinical benefits in terms of evaluating the health status of patients with the disease, according to the results of a prospective, observational cohort study (ClinicalTrials.gov Identifier: NCT0257486) conducted in South Korea and published in BMC Pulmonary Medicine.

Investigators from the Seoul National University Airway Registry sought to determine the efficacy of the CCQ and the appropriate CCQ cutoff threshold for individuals with more symptomatic COPD. During a period of 1 year, they enrolled a total of 126 patients with COPD >40 years of age who currently smoked or had smoked ≥10 packs/year. Correlations between the CCQ and the following measures were assessed: St. George’s Respiratory Questionnaire (SGRQ), COPD Assessment Test (CAT), modified Medical Round Council (mMRC) scale, lung function, and exercise capacity.

“More symptomatic patients” were defined as those individuals with SGRQ scores ≥25. Analyses were performed to determine which CCQ cutoff score was the most equivalent to an SGRQ score of 25. Of the 126 patients, 36.51% (n=46) recalled having experienced ≥1 acute COPD exacerbation 1 year prior to enrollment, and 13.49% (n=17) reported experiencing >2 exacerbations in the past year.

The CCQ correlated significantly with the SGRQ, the CAT, and the mMRC (r =0.76, 0.69, and 0.53, respectively). A CCQ cutoff point of 1.4 was predictive of an SGRQ score of 25, which demonstrated a better agreement rate and higher classification power compared with other cutoff points (area under the receiver operating curve = 0.605, 0.633, 0.681, 0.762, and 0.711 for the CCQ cutoff points of 0.7, 1.0, 1.2, 1.4, and 1.6, respectively). After adjusting for possible confounders, a CCQ score of 1.4 was a significant determinant of an SGRQ ≥25.

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The investigators concluded that a CCQ threshold of 1.4 showed a better agreement with other measures in patients with more symptomatic COPD compared with a cutoff of 1.0, which is suggested by a number of guidelines. Using a cutoff value of 1.4 may help to identify more symptomatic patients with COPD.


Jo YS, Park S, Kim DK, Yoo CG, Lee CH. The cutoff point of clinical chronic obstructive pulmonary disease questionnaire for more symptomatic patients. BMC Pulm Med. 2018;18(1):38.