Global Initiative for Chronic Obstructive Lung Disease 2011 symptom/risk assessment in α1-antitrypsin deficiency

BACKGROUND: The new GOLD (Global Initiative for Chronic Obstructive Lung Disease) strategy recommends use of the COPD Assessment Test (CAT) or modified Medical Research Council (mMRC) scale to assess symptoms in COPD against "risk" as assessed by spirometry or exacerbation frequency. We aimed to determine the concordance between CAT and mMRC scale in assessing risk in patients with α1-antitrypsin deficiency (AATD) and the CAT threshold for risk assessment at which similar proportions of patients are assigned into the risk categories.

METHODS: Distribution of 309 patients (protease inhibitor Z phenotype) in four GOLD categories (A, B, C, and D) was compared. Using CAT for symptoms, we compared patient distribution using scores between 10 and 15 to ascertain the CAT threshold at which the distribution of patients in each group is proportional.

RESULTS: Using CAT 10 and spirometry for risk assessment, 6.1% of patients were in group A (low symptoms/low risk), 39.2% in B (high symptoms/low risk), 2.3% in C (low symptoms/high risk), and 52.4% in D (high symptoms/high risk). Using mMRC scale and spirometry for risk produced a significantly different distribution from that using CAT (P < .0001). Using CAT 13 as a symptom threshold and spirometry for risk resulted in a more proportional distribution of patients, which was similar using CAT and exacerbation history (P > .0001) and mMRC scale and spirometry and/or exacerbation history for risk (P > .0001).

CONCLUSIONS: In patients with AATD, using either the mMRC scale 0 to 1 or CAT 10 scores to determine symptoms results in a significant difference in patient distribution. However, CAT 13 as the threshold for assessing symptoms results in a similar proportion of patients being categorized into the risk categories.