The 2011 Global Initiative for Chronic Obstructive Lung Disease (GOLD) strategy document recommends assessment of chronic obstructive pulmonary disease (COPD) using symptoms and future exacerbation risk, employing two score cut-points: COPD Assessment Test (CAT) score ≥ 10 or modified Medical Research Council dyspnoea scale (mMRC) grade ≥ 2. To explore the equivalence of these two symptom cut-points, the relationship between the CAT and the mMRC and St George's Respiratory Questionnaire (SGRQ), the Short-form Health Survey and the Functional Assessment of Chronic Illness Therapy Fatigue scores were retrospectively analysed using a primary care dataset. Data from 1817 patients (mean ± SD forced expiratory volume in 1 s 1.6 ± 0.6 L) showed a significant association between mMRC grades and all health status scores (ANOVA p<0.0001). mMRC grade 1 was associated with significant levels of health status impairment (SGRQ 39.4 ± 15.5 and CAT 15.7 ± 7.0); even patients with mMRC grade 0 had modestly elevated scores (SGRQ 28.5 ± 15.1 and CAT 11.7 ± 6.8). An mMRC grading ≥ 2 categorised 57.2% patients with low symptom (groups A and C) versus 17.2% with the CAT. Using the mMRC cut-point (≥ 1) resulted in similar GOLD group categorisations as the CAT (18.9%). The mMRC showed a clear relationship with health status scores; even low mMRC grades were associated with health status impairment. Cut-points of mMRC grade ≥ 1 and CAT score ≥ 10 were approximately equivalent in determining low-symptom patients. The GOLD assessment framework may require refinement.
