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Table 1 Baseline characteristics of each female cohort

From: Impact of sample size on the stability of risk scores from clinical prediction models: a case study in cardiovascular disease

   Development
(n = 1,865,079)
Validation
(n = 100,000)
Contemporary
(n = 387,557)
Outcome Total CVD events 82 065 4482 NA
  Total follow-up (years) 13 098 449 703 471 NA
Age   43.07 (15.94) 43.14 (15.96) 48.38 (14.43)
Systolic blood pressure   123.91 (18.28) 124 (18.22) 123.97 (15.17)
Body mass index   25.6 (5.60) 25.56 (5.56) 27.1 (6.31)
Cholesterol/high-density lipoprotein ratio   3.72 (1.20) 3.72 (1.21) 3.46 (1.04)
Smoking status Never 56.04% 56.15% 46.05%
  Ex 16.97% 16.98% 31.66%
  Current 27.00% 26.87% 22.29%
Townsend 1 (least deprived) 21.96% 21.96% 24.95%
  2 21.99% 21.81% 22.35%
  3 21.17% 21.46% 21.56%
  4 20.46% 20.36% 18.70%
  5 (most deprived) 14.42% 14.41% 12.44%
Treated hypertension   6.18% 6.19% 8.45%
Family history of CVD   15.08% 15.13% 20.86%
Type 2 diabetes   1.16% 1.19% 1.15%
  1. For continuous variables, the mean (standard deviation) is reported. There is no follow-up reported (NA) for the contemporary cohort because individuals entered the cohort on 1 Jan 2016, and follow-up in the CPRD extract stopped 3 months after this