Table 1.
Characteristics of subjects of a population-based nested case–control study of PD in Sweden, 2001–07
| Cases |
||||
|---|---|---|---|---|
| Variables | All cases | Primary diagnosis | Secondary diagnosis only | Controls |
| Number of subjects | 18 648 | 13 762 | 4886 | 93 240 |
| Age (years) at the index date, mean (SD) | 73.8 (10.0) | 71.7 (9.9) | 79.9 (7.7) | 73.8 (10.0) |
| Male, n (%) | 10 799 (57.9) | 8045 (58.5) | 2754 (56.4) | 53 995 (57.9) |
| CNS infections before the index date | ||||
| No | 18 562 | 13 710 | 4852 | 92 953 |
| Yes | 86 | 52 | 34 | 287 |
| Years before the index date | ||||
| <1 | 15 | 7 | 8 | 25 |
| 1–4 | 18 | 10 | 8 | 53 |
| 5–9 | 24 | 19 | 5 | 91 |
| ≥10 | 29 | 16 | 13 | 118 |
| Number of infections at least 5 years before the index date | ||||
| Once | 45 | 32 | 13 | 197 |
| ≥2 times | 8 | 3 | 5 | 12 |
| Duration of hospital stay at least 5 years before the index date (weeks) | ||||
| <1 | 22 | 16 | 6 | 84 |
| ≥1 | 31 | 19 | 12 | 125 |
| Sepsis before the index date | ||||
| No | 17 849 | 13 409 | 4440 | 90 662 |
| Yes | 799 | 353 | 446 | 2578 |
| Years before the index date | ||||
| <1 | 350 | 112 | 238 | 518 |
| 1–4 | 278 | 138 | 140 | 1178 |
| 5–9 | 120 | 69 | 51 | 611 |
| ≥10 | 51 | 34 | 17 | 271 |
| Number of infections at least 5 years before the index date | ||||
| Once | 155 | 95 | 60 | 824 |
| ≥2 times | 16 | 8 | 8 | 58 |
| Duration of hospital stay at least 5 years before the index date (weeks) | ||||
| <1 | 71 | 47 | 24 | 382 |
| ≥1 | 100 | 56 | 44 | 500 |
SD: standard deviation.