Table 8 Study findings on the impact of practice and specific practice-level factors on NHSHC uptake. AOR = adjusted odds ratio. OR = odds ratio. CI = confidence intervals. UR = uptake rate

Artac et al., 2013 [20]

Practice List Size Year 2 (all eligible patients)

> 10,000 vs. < 6000 (baseline): AOR = 6.05, 95% CI = 0.84–43.3, p < .010

Unexplained variance in models was interpreted as attributable to unmeasured practice factors

Year 1 unexplained variance = 19.4, 95% CI = 15.2–24.4%

Year 2 unexplained variance = 37.3, 95% CI = 30.6–44.6%

Attwood et al., 2016 [19]

Significant variance in uptake by practice

X²₂ = 74.61, p < .005

Adjusting analyses for GP Practice had a substantial effect on the strength and direction of associations between socio-demographic variables (specifically gender and IMD quintile; see relevant sections above) and uptake.

Cochrane et al., 2013 [23]

Practice Size

AOR = 1.03, 95% CI = 0.88–1.20, p > .100

Variance accounted for by individual practices = 12.7%, p < .001

Dalton et al., 2011 [24]

Practice List Size

< 3000 vs. 3000–5999 (baseline): AOR = 2.53, 95% CI = 1.09–5.84, p = .030

≥ 6000 vs. 3000–5999 (baseline): AOR = 0.79, 95% CI = 0.33–1.88, p = .599

Variance in models accounted for by practice = 28% (VPC = 0.28)

Gidlow et al., 2014 [9]

Variation in uptake by practice

X² = 336.9, p < .001

Variation in uptake by distance to practice

X² = 0.478, p = .924

Sallis et al., 2016 [21]

Of the five practices studied, one (used as baseline in analyses) had significantly higher uptake rates than all others (all p < .010).