Fig. 3From: Characterizing undiagnosed chronic obstructive pulmonary disease: a systematic review and meta-analysisMean difference (MD) in age, pack-years of smoking, mMRC dyspnea score, and percent of predicted FEV1 between diagnosed and undiagnosed categories. Persistent airflow limitation was defined as post-bronchodilator FEV1/FVC < 0.7. Squares represent individual study estimates with the size of the square corresponding to their weight in the pooled estimate (represented with diamonds). * modified Medical Research Council (mMRC) Dyspnea scale [26] means and standard errors (SE) for the diagnosed and undiagnosed categories are multiplied by a factor of 10Back to article page