| (Bentsen, Miaskowski, & Rustøen, 2014) | 100 patients | Cross-sectional study | NA | SGRQ | Age, Anxiety score | Number of comorbidities, Pain intensity, Depression score, Physical functions, GOLD Spirometrics staging, FEV1 % Predicted |
| (Bonsaksen, Haukeland-Parker, Lerdal, & Fagermoen, 2014) | 127 patients | Prospective longitudinal design | 12 months after course completion | Short Form 12, version 2 (SF-12v2), SF-36. | Work status, Illness perception | Age, Sex, Education, Physical activity, Self-efficacy |
| (Negi, Sarkar, Raval, Pandey, & Das, 2014) | 126 patients | A cross-sectional study | Between November 2011 and April 2012 | Hindi version of SGRQ | BMI, FEV1% predicted, FEV1/FVC%, MRC Dyspnea grade, Education, GOLD stage | Age, Sex, Area of residence, Smoking index, Seasonal variation |
| (Raherison et al., 2014) | 430 patients | A multicenter cross-sectional observational study | September 2009 to November 2010 | SGRQ-C | MRC dyspnea score, Number of treatments, Age, Anxiety, FEV1% predicted | Gold stage, Age, FEV1/FVC, BOD Index, No of exacerbation |
| (Abu Hassan, Abd Aziz, Hassan, & Hassan, 2014) | 117 patients | NA | January to June 2013 | CCQ | Smoking status, No of hospital admission due to COPD | No of days warded |
| (Justine, Tahirah, & Mohan, 2013) | 100 patients | Cross-sectional correlational study | NA | SF-36 v2 | Dyspnea score | Lung function |
| (Bentsen, Rokne, & Wahl, 2013) | 100 COPD patients and 3594 general population | A comparative survey design | Between August 2005 and August 2007. | SF-36 | COPD stage and severity | Age, Sex, Education level |
| (Obaseki, Erhabor, Awopeju, Obaseki, & Adewole, 2013) | 50 patients | a cross-sectional study | NA | SGRQ | Breathlessness, Weight loss, Smoking pack /year | Age, Sex, Smoking status, GOLD stage, FEV1/FVC %, BMI |
| (Burgel et al., 2013) | 326 patients | Cross-sectional analysis | Between January 2005 and August 2009. | HADS SGRQ
| FEV1%, Exacerbation/patient/year, Dyspnea, Low BMI, CAD/Comorbidity | Age, Smoking pack/year, Comorbidities, Current smokers, Sex |
| (Zamzam, Azab, El Wahsh, Ragab, & Allam, 2012) | 40 patients | NA | NA | SGRQ | GOLD stage, FEV1% predicted | Smoking index |
| (Joseph, Pascale, Georges, & Mirna, 2012) | 284 COPD patients from 2201 total sample | Cross-sectional study | Between October 2009 and September 2010 | CCQ | Cumulative cigarette dose, Older age, having at least one smoker in the family, Lower education, Female gender, Any heart disease, Heating house by diesel, Cumulative waterpipe dose | COPD severity scoring |
| (Han et al., 2011) | 224 African American and 1049 Caucasian subjects with COPD | Descriptive design | NA | SGRQ | Pack-year smoking history, Younger age, Lower FEV 1% predicted, mMRC, The number of exacerbations | Race |
| (Sundh, Ställberg, Lisspers, Montgomery, & Janson, 2011) | 1548 patients | Survey design/different setting | In 2005 | CCQ | Educational level, BMI, Heart disease, GOLD stage | Sex, Age, Smoking status, comorbidities |