Study characteristics summary of observational studies evaluating the association between diabetes and infection
| Characteristics | CS, n=243 | CCS, n=102 | Total, n=345 |
| Year of study, n (%) | |||
| <1990 | 4 (1.6) | 1 (1.0) | 5 (1.4) |
| 1990–1994 | 8 (3.3) | 4 (3.9) | 12 (3.5) |
| 1995–1999 | 8 (3.3) | 12 (11.8) | 20 (5.8) |
| 2000–2004 | 33 (13.6) | 20 (19.6) | 53 (15.4) |
| 2005–2009 | 64 (26.3) | 34 (33.3) | 98 (96.1) |
| 2010–2014 | 126 (51.8) | 31 (30.4) | 157 (45.5) |
| Mean age (range), no. of studies | 61.9 (28–80), n=172 | 55.9 (26–76), n=54 | 61.0 (26–80), n=226 |
| Male, n (%), no. of studies | 15 576 079 (47.0), n=210 | 705 950 (48.0), n=76 | 16 282 029 (48.3), n=286 |
| Mean follow-up (years), no. of studies | 4.4, n=70 | NA | 4.4, n=70 |
| Setting, n (%) | |||
| Hospital | 216 (88.9) | 85 (83.3) | 301 (87.2) |
| Clinic | 18 (7.4) | 11 (10.8) | 29 (8.4) |
| Hospital and clinic | 8 (3.3) | 5 (4.9) | 13 (3.8) |
| Long-term facilities | 1 (0.4) | 1 (1.0) | 2 (0.6) |
| Region, n (%) | |||
| Europe | 62 (25.5) | 38 (37.2) | 100 (29.0) |
| Asia | 61 (25.1) | 18 (17.6) | 79 (22.9) |
| North America | 111 (45.7) | 44 (43.0) | 155 (44.9) |
| South America | 7 (2.9) | 2 (2.0) | 9 (2.6) |
| Africa | 2 (0.8) | 0 (0) | 2 (0.6) |
| Population, n (%) | |||
| General population | 71 (29.2) | 54 (53.0) | 125 (36.2) |
| Cardiovascular disease | 72 (29.6) | 18 (17.6) | 90 (26.1) |
| Bone disease | 16 (6.6) | 7 (6.9) | 23 (6.7) |
| Kidney disease | 17 (7.0) | 4 (3.9) | 21 (6.1) |
| Malignancy | 14 (5.8) | 2 (2.0) | 16 (4.6) |
| Gastrointestinal disease | 10 (4.1) | 3 (2.9) | 13 (3.8) |
| Spine disease | 10 (4.1) | 2 (2.0) | 12 (3.5) |
| Organ transplant | 7 (2.9) | 4 (3.9) | 11 (3.2) |
| Genitourinary disease | 8 (3.3) | 1 (1.0) | 9 (2.6) |
| Critically ill | 4 (1.6) | 5 (4.9) | 9 (2.6) |
| Pregnancy | 4 (1.6) | 0 (0) | 4 (1.2) |
| Burn | 3 (1.2) | 0 (0) | 3 (0.9) |
| Ophthalmologic | 0 (0) | 2 (2.0) | 2 (0.6) |
| Respiratory disease | 2 (0.8) | 0 (0) | 2 (0.6) |
| Obesity | 1 (0.4) | 0 (0) | 1 (0.3) |
| Breast reconstruction | 3 (1.2) | 0 (0) | 3 (0.9) |
| Autoimmune disease | 1 (0.4) | 0 (0) | 1 (0.3) |
| Outcome, n (%) | |||
| Not specified infections | 36 (14.8) | 12 (11.8) | 48 (13.9) |
| Skin and soft tissue infections | 114 (46.9) | 36 (35.3) | 150 (43.5) |
| Respiratory tract infections | 17 (7.0) | 14 (13.7) | 31 (9.0) |
| Genitourinary infections | 18 (7.4) | 11 (10.8) | 29 (8.4) |
| Gastrointestinal infections | 1 (0.4) | 6 (5.9) | 7 (2.0) |
| Head and neck infections | 1 (0.4) | 2 (2.0) | 3 (0.9) |
| Blood infections | 16 (6.6) | 10 (9.8) | 26 (7.5) |
| Viral infections | 7 (2.9) | 4 (3.9) | 11 (3.2) |
| Bone infections | 2 (0.8) | 2 (2.0) | 4 (1.2) |
| Other infections | 1 (0.4) | 4 (3.9) | 5 (1.4) |
| Multiple infections | 30 (12.3) | 1 (1.0) | 31 (9) |
| NOS, n (%) | |||
| Weak (score 0–3) | 0 (0) | 0 (0) | 0 (0) |
| Moderate (score 4–6) | 197 (81.0) | 82 (80.4) | 279 (80.9) |
| Strong (score 7–9) | 46 (19.0) | 20 (19.6) | 66 (19.1) |
CCS, case–control studies; CS, cohort studies; NA, not applicable; NOS, Newcastle-Ottawa Quality Assessment Scale.