Health status assessment in routine clinical practice: the chronic obstructive pulmonary disease assessment test score in outpatients

Respiration. 2012;84(3):193-9. doi: 10.1159/000336549. Epub 2012 Mar 22.


Background: The chronic obstructive pulmonary disease (COPD) assessment test (CAT) is a simple, self-completion questionnaire developed to measure health status in patients with COPD, which is potentially suitable for routine clinical use.

Objectives: The purpose of this study was to establish the determinants of the CAT score in routine clinical practice.

Methods: Patients attending the clinic completed the CAT score before being seen. Clinical data, including, where available, plethysmographic lung volumes, transfer factor and arterial blood gas analysis, were recorded on a pro forma in the clinic.

Results: In 224 patients (36% female), mean forced expiratory volume in 1 s (FEV₁) was 40.1% (17.9) of predicted (%pred); CAT score was associated with exacerbation frequency [0-1/year 20.1 (7.6); 2-4/year 23.5 (7.8); >4/year 28.5 (7.3), p < 0.0001; 41/40/19% in each category] and with Medical Research Council (MRC) dyspnoea score (r² = 0.26, p < 0.0001) rising approximately 4 points with each grade. FEV(1) %pred had only a weak influence. Using stepwise regression, CAT score = 2.48 + 4.12 [MRC (1-5) dyspnoea score] + 0.08 (FEV(1) %pred) + 1.06 (exacerbation rate/year)] (r² = 0.36, p < 0.0001). The CAT score was higher in patients (n = 54) with daily sputum production [25.9 (7.5) vs. 22.2 (8.2); p = 0.004]. Detailed lung function (plethysmography and gas transfer) was available in 151 patients but had little influence on the CAT score.

Conclusion: The CAT score is associated with clinically important variables in patients with COPD and enables health status measurement to be performed in routine clinical practice.

Publication types

  • Comparative Study
  • Research Support, Non-U.S. Gov't

MeSH terms

  • Female
  • Follow-Up Studies
  • Health Status*
  • Humans
  • Lung / physiopathology*
  • Male
  • Middle Aged
  • Outpatients*
  • Prospective Studies
  • Pulmonary Disease, Chronic Obstructive / diagnosis*
  • Pulmonary Disease, Chronic Obstructive / physiopathology
  • Respiratory Function Tests
  • Severity of Illness Index
  • Surveys and Questionnaires