Baseline demographic characteristics of the study population (CPRD GOLD)
| Total | Case group (n = 17 320) | Control group (n = 99 320) |
|---|---|---|
| Sex, n (%) | ||
| Male | 8282 (47.82) | 47 491 (47.82) |
| Female | 9038 (52.18) | 51 829 (52.18) |
| Age at index, years, median (IQR) | 51 (36–64) | 50 (36–64) |
| Region, n (%) | ||
| London | 2457 (14.19) | 14 023 (14.12) |
| South England | 7227 (41.73) | 41 626 (41.91) |
| Midlands and East England | 3831 (22.12) | 21 924 (22.07) |
| North England | 3805 (21.97) | 21 747 (21.90) |
| Number of GP consultations before the | ||
| index date, median (IQR) | ||
| 4–5 years before index date | 7 (2–13) | 5 (2–12) |
| 3–4 years before index date | 8 (3–15) | 6 (2–12) |
| 2–3 years before index date | 8 (3–16) | 6 (2–13) |
| 1–2 years before index date | 10 (5–18) | 8 (4–15) |
| 0–1 year before index date | 11 (5–19) | 8 (4–15) |
| Socioeconomic status, IMD quintile, n (%)a | ||
| 1 (least deprived) | 4020 (23.21) | 23 997 (24.16) |
| 2 | 3830 (22.11) | 22 405 (22.56) |
| 3 | 3422 (19.76) | 19 553 (19.69) |
| 4 | 3343 (19.30) | 18 775 (18.90) |
| 5 (most deprived) | 2695 (15.56) | 14 533 (14.63) |
CPRD = Clinical Practice Research Datalink. IMD = Index of Multiple Deprivation. IQR = interquartile range.
↵a Missing data: cases 10 (0.06%) and controls 57 (0.06%).