Background The COPD assessment tool (CAT) measures health status1 and is responsive to change with pulmonary rehabilitation2 and out-patient exacerbations of COPD (AECOPD)3. This study established i) CAT score at AECOPD hospital admission, ii) change during recovery and iii) CAT in relation to other outcome measures of COPD severity at stability.
Methods Consenting patients presenting to hospital with a clinical diagnosis of AECOPD self-completed the CAT and answered detailed history. Length of stay (LOS) was recorded. At four week follow-up assessment, the CAT score, MRC dyspnoea score, spirometry and six-minute walking distance (6MWD) were measured.
Results Of 153 patients recruited at admission, there were 5 in-patient deaths, all with a high (>20) CAT on admission. Median LOS per admission CAT category was CAT10–20: 2.5 days; CAT21–30: 4 days; CAT31–40: 5 days.
89 subjects were reassessed at 4 weeks and 72 had a clinical diagnosis of COPD confirmed, Table 1. In these subjects, the mean (95%CI) change in CAT score from admission was -7(-9, -5), p < 0.001. Whilst 61/72 had a high CAT score on admission, there remained 39/72 with high score at follow-up. CAT score at follow-up was related to 6MWD, r = 0.34, p < 0.01 but not to age or forced expiratory volume in one second (FEV1)% predicted.
Conclusion Despite marked improvement in CAT score with recovery from an AECOPD requiring hospital admission, a large proportion persist with high CAT scores at 4 weeks indicating poor health status. The CAT score offers prognostic information and adds another dimension to the COPD assessment.
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