Table 1 Primary Studies Included in the Meta-analysis
Study | Country | Design | Case Subjects | Control Subjects | Method of GERD Diagnosis | Method of COPD Diagnosis | Criteria of COPD exacerbation | Follow up |
|---|---|---|---|---|---|---|---|---|
Bigatao et al. (2018) [16] | United States | cohort study | 21 COPD patients with GERD | 27 COPD patients without GERD | pH-metry: DeMeester score > 14.7 | FEV1/FVC <88% pre after bronchodilator use and no response to bronchodilator (albuterol, 400 mcg) | occurrence of increase in respiratory symptoms [(dyspnea, cough, and sputum (purulent or not)] that required the use of antibiotics and/or oral corticosteroids | 12 months |
Lin et al. (2015) [17] | Taiwan | cohort study | 1976 COPD patients with GERD | 3936 COPD patients without GERD | NOT stated | The diagnosis of COPD was identified based on the International Classification of Diseases, 9th Revision, Clinical Modification codes (ICD-9-CM codes 491, 492, 496) | COPD-related ED admission or hospitalisation during which the subject received bronchodilators or steroids during the one-year follow-up. | 12 months |
Benson et al. (2015) [18] | United Kingdom | cohort study | 547 COPD patients with GERD | 1558 COPD patients without GERD | Questionnaire | smoking history ≥10 pack years, a post-bronchodilator Forced Expiratory Volume in 1 s (FEV1) < 80% of predicted value, and FEV1/FVC ≤ 0.7 | Patients treated with antibiotics and/or systemic corticosteroids, or requiring hospitalisation were included | 3 years |
Martinez et al. (2014) [19] | United States | cross -sectional study | 1307 COPD patients with GERD | 3176 COPD patients without GERD | Self-report of physician-diagnosed GERD | met criteria for GOLD stage 1 or greater (fixed airflow obstruction with a post-bronchodilator FEV1/FVC ≤ 0.7), CT measurements of emphysema and airway abnormalities | ATS Chronic Respiratory Disease Questionnaire (ATS-DLD-78) | NOT stated |
Shimizu et al. (2012) [20] | Japan | cohort study | 40 COPD patients | 40 control subjects | The frequency of scale for the symptoms of GERD (FSSG) questionnaire: total score>8 points | GOLD criteria | worsening that required an unscheduled visit to the local doctor, emergency department, or hospital, or else needed treatment with oral or intravenous corticosteroids at least one episode during the past two years | Not stated |
Takada et al. (2011) [21] | Japan | cohort study | 59COPD patients with GERD | 162 COPD patients without GERD | FSSG questionnaire: total score>8 points | symptoms of chronic sputum or dyspnea on effort and FEV1/FVC < 70% after use of a bronchodilator | AECOPD was defined based on symptoms of Anthonisen type 1 or 2 and prescription of additional systemic corticosteroids or antibiotics | 1 year |
Terada et al. (2010) [9] | Japan | cohort study | 67 patients with COPD | 19 age-matched controls | FSSG questionnaire: total score>8 points | Not stated | the presence of an increase in any two major symptoms (dyspnea, sputum purulence, and sputum quantity) or an increase in one major and one minor symptom (wheeze, sore throat, cough, and nasal congestion/discharge) for at least two consecutive days | 12 months |
Rogha et al. (2010) [22] | Iran | cohort study | 59 COPD patients with GERD | 51 COPD patients without GERD | Mayo gastro-oesophageal reflux questionnaire (GORQ) | FEV1/FVC < 0.7,age ≥ 40 years, and a ≥ 20 pack-year history of smoking or history of exposure to occupational dusts or chemicals for ≥10 years | increase in cough frequency and severity, increase in dyspnea, or change in the amount and/or character of sputum | 1 year |
Terada et al. (2008) [8] | Japan | cohort study | 82 patients with COPD | 40 controls | FSSG questionnaire: total score>8 points | (GOLD) 2003 | the occurrence of two or more of three major symptoms (ie, increase in dyspnoea, sputum purulence and increased sputum volume), or any one major symptom with any one minor symptom (ie, increase in nasal discharge, wheezing, sore throat, cough or fever) for at least 2 consecutive days | Over 6 months |
Rascon-Aguilar et al. (2006) [23] | United States | cross -sectional survey | 32 patients with COPD | 54 COPD patients without GERD | Mayo Clinic GERD questionnaire | FEV1/FVC ratio ≤ 70% on pulmonary function tests (PFTs),age ≥ 40 years, and a ≥ 20 pack-year history of smoking | worsening dyspnea, increasing volume of sputum, or purulent sputum in conjunction with physician-initiated use of corticosteroids or antibiotics, hospitalization, or emergency department (ED) visit during the previous 12 months |