Fig. 3From: Assessment of comorbidities and prognosis in patients with COPD diagnosed with the fixed ratio and the lower limit of normal: a systematic review and meta-analysisForest plot of exacerbation for different diagnostic criteria, compared with those met neither (FR+/LLN+: FEV1/FEV < 0.7 and FEV1/FVC < LLN, FR+/LLN-: FEV1/FEV < 0.7 but FEV1/FVC > LLN, FR−/LLN+: FEV1/FEV ≥ 0.7 but FEV1/FVC < LLN)Back to article page