Impact of the National Health Service Health Check program, stratified by individual risk levels before the intervention (n = 138 788)
| Outcome and pre-intervention risk category | n | Timeframe; mean ± SD | Difference, by paired t test (95% CI) | Crude DID (95% CI) | DID matching estimator (95% CI) | |
|---|---|---|---|---|---|---|
| Before intervention | After intervention | |||||
| Systolic BP, mm Hg | ||||||
| BP < 140/90 mm Hg | ||||||
| Attendees | 19 028 | 122.2 ± 10.6 | 125.7 ± 10.9 | 3.58 (3.43 to 3.74) | 0.35 (0.19 to 0.51) | −1.20 (−1.51 to −0.89) |
| Nonattendees | 84 455 | 123.5 ± 10.0 | 126.7 ± 9.8 | 3.23 (3.16 to 3.30) | ||
| BP ≥ 140/90 mm Hg | ||||||
| Attendees | 10 644 | 149.3 ± 13.3 | 137.5 ± 12.2 | −11.7 (−12.0 to −11.4) | −4.23 (−4.54 to −3.92) | −3.22 (−3.63 to −2.81) |
| Nonattendees | 24 661 | 145.5 ± 10.3 | 137.9 ± 11.5 | −7.54 (−7.70 to −7.38) | ||
| Diastolic BP, mm Hg | ||||||
| BP < 140/90 mm Hg | ||||||
| Attendees | 19 028 | 75.5 ± 7.6 | 76.6 ± 6.8 | 1.12 (1.01 to 1.23) | −0.13 (−0.24 to −0.02) | −0.65 (−0.85 to −0.44) |
| Nonattendees | 84 455 | 76.5 ± 6.8 | 77.8 ± 6.1 | 1.26 (1.21 to 1.30) | ||
| BP ≥ 140/90 mm Hg | ||||||
| Attendees | 10 644 | 88.6 ± 9.5 | 81.8 ± 8.0 | −6.79 (−6.98 to −6.60) | −2.59 (−2.80 to −2.39) | −2.05 (−2.32 to −1.78) |
| Nonattendees | 24 661 | 86.2 ± 8.2 | 82.0 ± 7.3 | −4.20 (−4.30 to −4.09) | ||
| Body mass index (BMI) | ||||||
| BMI < 30 | ||||||
| Attendees | 21 238 | 25.1 ± 2.8 | 25.3 ± 2.9 | 0.18 (0.17 to 0.20) | −0.17 (−0.18 to −0.15) | −0.23 (−0.30 to −0.16) |
| Nonattendees | 91 282 | 25.6 ± 2.6 | 26.0 ± 2.7 | 0.36 (0.35 to 0.36) | ||
| BMI ≥ 30 | ||||||
| Attendees | 8 434 | 34.2 ± 3.9 | 33.8 ± 4.0 | −0.42 (−0.46 to −0.38) | −0.42 (−0.47 to −0.37) | −0.30 (−0.39 to −0.21) |
| Nonattendees | 17 834 | 33.5 ± 3.7 | 33.5 ± 3.9 | −0.003 (−0.02 to 0.02) | ||
| Total cholesterol, mmol/L | ||||||
| Total cholesterol < 5 mmol/L | ||||||
| Attendees | 8 979 | 4.3 ± 0.4 | 4.6 ± 0.5 | 0.29 (0.28 to 0.30) | 0.05 (0.04 to 0.06) | −0.08 (−0.10 to −0.05) |
| Nonattendees | 24 928 | 4.6 ± 0.4 | 4.8 ± 0.5 | 0.24 (0.23 to 0.24) | ||
| Total cholesterol ≥ 5 mmol/L | ||||||
| Attendees | 20 693 | 6.0 ± 0.7 | 5.6 ± 0.7 | −0.44 (−0.45 to −0.43) | −0.34 (−0.35 to −0.33) | −0.13 (−0.15 to −0.11) |
| Nonattendees | 84 188 | 5.6 ± 0.5 | 5.5 ± 0.5 | −0.09 (−0.09 to −0.08) | ||
Note: BP = blood pressure, CI = confidence interval, Crude DID = difference-in-differences without matching, DID = difference-in-differences, SD = standard deviation.