Table 4.
Differences (95 % CIs): INTERVAL cohort versus NHSBT general donor population and INTERVAL randomised versus not randomised
| Demographics | INTERVAL cohort | |||||
|---|---|---|---|---|---|---|
| mean or proportion (%)a | INTERVAL cohort | NHSBT general donor population | Difference (95 % CI) | Randomised | Not randomised | Difference (95 % CI) |
| Sex: Male (%) | 49.7 % | 44.1 % | 5.7 % (5.2 %, 6.1 %) | 49.6 % | 50.8 % | -1.2 % (-2.9 %, 0.6 %) |
| Age at baseline (years) | 43.1 | 42.3 | 0.73 (0.59, 0.87) | 43.3 | 39.9 | 3.37 (2.88, 3.86) |
| Ethnicity: White (%) | 94.5 % | 95.0 % | -0.5 % (-0.7 %, -0.3 %) | 94.9 % | 89.4 % | 5.5 % (4.5 %, 6.6 %) |
| Blood group: O (%)b | 47.6 % | 47.3 % | 0.4 % (-0.1 %, 0.8 %) | 47.6 % | 47.9 % | -0.2 % (-2.0 %, 1.5 %) |
| Distance to nearest static donor centre (miles) | 6.29 | 18.1 | -11.8 (-12.0, -11.7) | 6.37 | 5.24 | 1.12 (0.82, 1.43) |
| Number of all donationsc | 3.28 | 2.24 | 1.04 (1.02, 1.06) | 3.33 | 2.61 | 0.73 (0.66, 0.80) |
| Deferral for low haemoglobin (%)c | 6.8 % | 4.7 % | 2.1 % (1.8 %, 2.3 %) | 6.8 % | 6.2 % | 0.6 % (-0.2 %, 1.5 %) |
| Any other deferral (%)c | 30.0 % | 24.6 % | 5.4 % (5.0 %, 5.8 %) | 30.1 % | 28.8 % | 1.3 % (-0.2 %, 2.9 %) |
| Length of NHSBT donation history at baseline (years) | 10.7 | 8.58 | 2.15 (2.07, 2.22) | 10.9 | 8.47 | 2.43 (2.14, 2.72) |
aThose with missing values excluded
bBlood group O includes both RhD groups
cDuring the 2 years prior to baseline