Methods: We performed a systematic review (PubMed, CINAHL, EMBASE) to identify observational studies that reported prevalence of COPD in case finding and early diagnosis and calculated a weighted prevalence for each one of the groups. We also searched for studies that determined the accuracy of questionnaires and hand-held expiratory flow meter PiKo-6®, using spirometry as a gold standard (post-bronchodilator FEV^ FVC< 70%) for the diagnosis of COPD. Two of the authors independently selected studies that met the inclusion