Table 1.
Characteristics of the included studies with the timescale starting from the inception of the databases up to April 2017
| Article | Study type | Population | Method of identification | Country | Race | Mean age in years (SD) | Females | Obesity (%) | Smoking status | % OA reported | Weighted mean |
|---|---|---|---|---|---|---|---|---|---|---|---|
| Schnell et al30 | Cross- sectional | 995 with COPD from NHANES | Search | USA | % (95% CI): White: 84.6 (81.4–87.4); Black: 6.8 (5.1–8.9); Hispanic: 4.4 (3.0–6.3) | 62.7 (95% CI 61.7–63.8) | 60.1% | 40.3% | Ever smoked (68.9%); >10 pack-years (43%) | 54.6% | 0.54% |
| Westerik et al31 | Retrospective cohort study | 14,603 with COPD from health records in Dutch general practices | Search | the Netherlands | Not reported | 66.5 (SD 11.5) | 46.9% | 4.4% | Not reported | 17.6% | 2.53% |
| Rai et al32 | Cross- sectional | 608 with COPD out of 1,889 from Birmingham COPD cohort study | Manual search | UK | Not reported | Age: 38–49 (11.2%); 50–59 (41.6%); 60–64; (47.2%) | 43.6% | BMI (kg/m2): underweight (<18.5) = 2.8%; normal weight (18.5–24.9) = 26.8%; overweight (25.0–29) = 35.2%; obese (30.0–39) = 29.6%; morbidly obese (>40.0) = 5.7% | Current smokers (49.7%); ex-smokers (42.8%); never smoked (7.5%) | 16.8% | 0.10% |
| Lee et al33 | Cohort study | 15,540 with COPD (55–64 years) from National Veterans Health Administration database | Manual search | USA | Not reported | 59.3 (3.1) | Not reported (mostly males) | Not reported | Not reported | 20% | 3.07% |
| Garin et al34 | Cross- sectional study | 3,339 with COPD from 41,909 adults >50 years from nine countries | Search | Nine countries: China, Ghana, India, Mexico, Russia, South Africa, Finland, Spain and Poland | Not reported | Not reported | Not reported | 19% | Not reported | 44% | 1.45% |
| Kumbhare et al35 | Cross- sectional, observational study | 4,807 with COPD from the 2012 BRFSS, an annual random digit-dialed telephone survey | Search | USA | White, non- Hispanic (82.9%); Black, non-Hispanic (8.2%); other race, non- Hispanic (3%); multiracial, non- Hispanic (2.8%); Hispanic (1.8%) | 67.1 (SD 11.8) | 61.6% | BMI (kg/m2) categories: underweight (<18.5) = 7%; normal weight (18.5–24.9) = 29.8%; overweight (25.0–29.9) = 30.9%; obese (30.0–39.9) = 26.3%; morbidly obese (>40.0) = 6.1% | Current smokers (34.3%); ex-smokers (45.5%); never smoked (20.2%) | 61.2% | 2.9% |
| Lalkhen and Mash36 | Cross- sectional study | 140 with COPD from primary health care facilities in South Africa | Search | South Africa | Not reported | Not reported | Not reported | Not reported | Not reported | 12.1% | 0.02% |
| Park et al37,* | Retrospective cohort | 1,905 with COPD from the database of the fourth and fifth (2007–2012) KNHANES | Search | Korea | Not reported | 64.5 (10.2) | 32% | BMI (kg/m2) categories (<18.5) = 3.3%; (18.5–23.0) = 68.2%; (≥23.0) = 28.5% | Current smokers (39.6%); ex-smokers (17.6%); never smoked (42.8%) | 11.9% | 0.22% |
| Putcha et al38 | Cohort study | 3,690 African- Americans and non-Hispanic Whites among GOLD 2–4 COPD patients | Search | USA | African- Americans (23%); non- Hispanic Whites (77%) | 63.4 (8.5) | 44% | Mean BMI (SD) 28.1 (6.3) | Current smokers (40.7%) | 20.7% (calculated not reported) | 0.75% |
| Schwab et al39 | Retrospective cohort study | 52,643 with COPD from US claims database (Humana Inc., Louisville, KY, USA) | Search | USA | Not reported | 70.6 (9.6) | 55% | 19.65% | Not reported | 43.8% | 22.7% |
| Mapel et al40,** | Case–control study | 200 with COPD from 1,522 from the Managed Care Database, New Mexico | Manual search | USA | Hispanic (17.8%); non- Hispanic (82.2%) | 67.5 | 48.9% | Not reported | Current smokers (46%); ex-smokers (34%); never smoked (14.5%) | 22% (moderate- to-severe arthritis only) | 0.04% |
| Wijnhoven et al41 | Cross- sectional study | 161 with COPD from 25 primary care practices in the Netherlands | Manual search | the Netherlands | Not reported | 61 (10.3) | 44.7% | Not reported | Not reported | 23% | 0.04% |
| Yeo et al42 | Observational cohort study | 27 with COPD ≥70 years from the UK primary care | Manual search | UK | Not reported | 76 (4.36) | 40.7% | Not reported | Not reported | 74% | 0.02% |
| Karch et al43 | Cohort study | 2,741 with COPD from 31 centers in Germany | Manual search | Germany | Not reported | 65.1 (8.6) | 41% | Mean BMI (SD) 27.0 (5.4) | Current smokers (24%); ex-smokers (68%); never smoked (8%) | 40.1% | 1.08% |
| Total = 101,399 | Total = 35.5% |
Notes:
*
The characteristics of the percentage of males and the mean age are for the overall sample in the original study (n = 2,108) not for the patients included in our analysis (n = 1,905).
**
The characteristics of the percentage of males and the mean age are for the overall sample in the original study (n = 1,522) not for the patients included in our analysis (n = 200). Smoking history not documented for 5.5% of the patients.
Abbreviations: BMI, body mass index; BRFSS, Behavioral Risk Factor Surveillance System; KNHANES, Korean National Health and Nutrition Examination Survey; NHANES, National Health and Nutritional Examination Study; OA, osteoarthritis; GOLD, Global Initiative for Obstructive Lung Disease scale.