First author [ref.] | Study design | Sample size | Age years | GOLD severity | Readmission time | Causes and rates of readmission, in order of prevalence | Study quality |
Almagro [17] | P | Total: n=983 M: n=899 (92%) F: n=84 (8%) | 72.25±9.7 | GOLD 3 | 90 day and 1 year |
| Good |
Baker [18] | R | Total: n=6095 M: n=2499 (40.8%) F: n=3596 (59.2%) | 40–65 | Not reported | 1, 3 and 12 months |
| Good |
Bashir [19] | R | Total: n=461 M: n=311 (67.5%) F: n=150 (32.5%) | 71.7±13.3 | Not reported | 30 days | Overall rate: 16.5% | Good |
Bollu [20] | R | Total: n=2463 M: n=1054 (43%) F: n=1409 (57%) | 72.5±12 | Not reported | 30 days | Overall rate: 20.6%
| Good |
Bottle [21] | R | Total: n=96 053 M: n=46 388 (48.3%) F: n=49 665 (51.7%) | 36-≥85 | Not reported | 30 days | Overall rate: 16.5%
| Good |
Candrilli [22] | R | Total: n=264 526 M: n=129 769 (49%) F: n=134 757 (51%) | 30 days=67.69±11.26 90 days=67.42±11.23 | Not reported | 30 days and 90 days |
| Good |
Chan [23] | R | Total: n=65 497 M: n=50 456 (77%) F: n=15 041 (23%) | 76.81±9.6 | Not reported | 30 days |
| Good |
Chawla [24] | P | Total: n=54 M: n=30 (55%) F: n=24 (45%) | 70±12 | GOLD 3 | 30 days |
| Fair |
Choi [25] | R | Total: n=704 M: n=492 (70%) F: n=212 (30%) | 72.4±9.5 | GOLD 2–3 | 30 days |
| Good |
Couillard [26] | R | Total: n=167 M: n=86 (51.5%) F: n=81 (48.5%) | 71.4±10.3 | GOLD 2 | 1 year |
| Good |
Echevarria [27] | P | Total: n=2417 M: n=1119 (46%) F: n=1298 (54%) | 72.5±10.1 | GOLD 3 | 90 day |
| Good |
Epstein [28] | R | Total: n=539 M: n=325 (60%) F: n=214 (40%) | 69.19±11.75 | Not reported | 60 day |
| Good |
Ehsani [29] | P | Total: n=42 M: n=28 (66.7%) F: n=14 (33.3%) | 70±8.6 | Not reported | 30 day |
| Fair |
Genao [30] | R | Total: n=52 741 M: n=23 397 (44%) F: n=29 344 (56%) | 71.4±10.3 | Not reported | 30 day, 1 year and 3 years |
| Good |
Goto [31] | R | Total: n=845 465 M: n=350 967 (41%) F: n=494 498 (59%) | 69±0.01 | Not reported | 30 days |
| Good |
Gershon [32] | R | Total: n=126 013 M: not presented F: not presented | 35–85+ | Not reported | 30 days |
| Good |
Hakim [33] | R | Total: n=2662 M: n=1418 (53%) F: n=1244(47%) | 72.5±12 | Not reported | 30 days and 1 year |
| Fair |
Hijjawi [34] | P | Total: n=160 M: n=76 (47.5%) F: n=84 (52.5%) | 65.77±12.47 | GOLD 1–4 | 30 days |
| Good |
Jacobs [35] | R | Total: n=1 055 830 M: n=437 812 (41%) F: n=618 018 (59%) | 68 (58–77) | Not reported | 3, 7 and 30 days |
| Good |
Kon [36] | P | Total: n=213 M: n=111 (52%) F: n=102 (48%) | 72.1±10.8 | GOLD 3 | 90 days |
| Good |
Loh [37] | R | Total: n=123 M: n=65 (52.8%) F: n=58 (47.2%) | 64.9±11.3 | GOLD 3 | 30 and 90 days |
| Good |
Nguyen [38] | R | Total: n=4596 M: n=2040 (44%) F: n=2556 (56%) | 72.3±11 | GOLD 2 | 30 days |
| Good |
Nguyen [39] | R | Total: n=2910 M: n=1248 (43%) F: n=1662 (57%) | 72±11 | GOLD 2 | 30 days |
| Good |
Rinne [40] | R | Total: n=20 472 M: not presented F: not presented | 73 | Not reported | 30 days |
| Good |
Rinne [41] | R | Total: n=33 558 M: n=32 417 (96.6%) F: n=1141 (3.4%) | 68.7 | Not reported | 30 days |
| Good |
Roberts [42] | R | Total: n=306 M: n=135 (44%) F: n=171 (56%) | 71 | Not reported | 30 and 90 days |
| Good |
Shah [43] | R | Total: n=947 084 M: n=392 187 (41.41%) F: n=554 897 (58.59%) | 73.55±10.87 | Not reported | 30 days |
| Good |
Sharif [44] | R | Total: n=8263 M: n=3401 (41%) F: n=4862 (59%) | 56.55±5.73 | Not reported | 30 days |
| Good |
Simmering [45] | R | Total: n=286 313 M: n=13 0497 (45.5%) F: n=155 816 (54.5%) | 40–90+ | Not reported | 30 days |
| Good |
Singh [46] | R | Total: n=135 498 M: n=53 940 (38.80%) F: n=81 558 (62%) | 66–74, 75–84, ≥85 | Not reported | 30 days |
| Good |
Spece [47] | R | Total: n=2391 M: n=2319 (97%) F: n=72 (3%) | 68.0±10.4 | Not reported | 30 days |
| Good |
Tzy-Chyi Yu [48] | R | Total: n=18 282 M: n=6869 (37.6%) F: n=11 413 (62.4%) | 56.6±5.8 | Not reported | 30 days |
| Good |
Data are presented as mean±sd or range, unless otherwise stated. GOLD: The Global Initiative for Chronic Obstructive Lung Disease; P: prospective; R: retrospective; M: male; F: female; SABA: short-acting beta agonist; AECOPD: acute exacerbations of COPD; MI: myocardial infarction; PIF: peak inspiratory flow.