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Table 3 Effect of the intervention on clinical practice and patient outcomes

From: Economic evaluation of the NET intervention versus guideline dissemination for management of mild head injury in hospital emergency departments

Variable No. of patients (EDs) N (%)/mean (SE) Increment, raw (95%CI)^ Increment, adjusted (95%CI)
Rx Control Rx Control
Clinical practice outcomes (NET sample)
 PTA1 893 (14) 1050 (17) 117 (13.1%) 12 (1.1%) 11.96% (9.8, 14.1) 13.63% (8.3, 19.0)
 INFO 785 (14) 944 (17) 160 (20.4%) 175 (18.5%) 1.84% (− 1.9, 5.6) 3.15% (− 3.0, 9.3)
 SAFED2 402 (14) 413 (17) 14 (3.5%) 0 (0%) 3.49% (1.0, 6.0)
Clinical outcomes and quality of life (NET-Plus sample)
 Anxiety3 125 (10) 218 (14) 3.43 (0.32) 4.27 (0.27) − 0.83 (− 1.69, 0.02) − 0.52 (− 1.34, 0.30)††
 Rivermead4 125 (10) 218 (14) 4.73 (0.49) 6.68 (0.59) − 1.96 (3.65, 0.26) − 1.15 (− 2.77, 0.48)††
 HRQoL5 123 (10) 208 (14) 0.805 (0.01) 0.776 (0.01) 0.029 (− 0.00, 0.06) 0.030 (− 0.00, 0.06)
  1. ^Increment, raw = unconditional difference in absolute risk or average scores due to exposure to the intervention from two sample t test with equal variances
  2. Increment, adjusted = difference in absolute risk due to exposure to the intervention; adjusted for the following minimisation factors and pre-specified confounders: age, sex, out_of_hours, rurality, mTBI protocol, ED participation in NET-Plus, and annual_presentation_rate. Estimates derived from margins, dydx(i.study_group) after xtgee, family(binomial) link(logit) corr(exchangeable) vce(robust) to account for within-cluster correlation structure and yielding cluster-robust standard errors even if the correlation structure is misspecified
  3. ††Increment, adjusted = difference in average scores due to exposure to the intervention; adjusted for the following minimisation factors and pre-specified confounders: age, sex, out_of_hours, rurality, mTBI protocol, and annual_presentation_rate. Estimates derived from margins, dydx(i.study_group) after xtgee, family(Gaussian) link(identity) corr(independent) vce(robust) to account for within-cluster correlation structure and yielding cluster-robust standard errors even if the correlation structure is misspecified
  4. ‡Increment, adjusted = difference in average scores due to exposure to the intervention; adjusted for the following minimisation factors and pre-specified confounders: age, sex, out_of_hours, rurality, mTBI protocol, and annual_presentation_rate. Estimates derived from margins, dydx(i.study_group) after xtgee, family(Gaussian) link(log) corr(independent) vce(robust) to account for within-cluster correlation structure and yielding cluster-robust standard errors even if the correlation structure is misspecified
  5. 1Primary outcome for the economic evaluation
  6. 2Defined as PTA, INFO, and CT where CT denotes whether a CT scan was provided in the presence of a risk factor that justifies the scan (age 65 or older; GCS < 15; amnesia; suspected skull fracture; vomiting and coagulopathy) [26] (assessed in the cohort of patients for whom risk criteria were recorded only). CT therefore indicates whether a scan was appropriately provided but not whether a scan was ‘appropriately denied’. CT and SAFED only assessed in the cohort of patients for whom risk criteria were recorded
  7. 3Anxiety measured using the relevant questions in the Hospital Anxiety and Depression Scale giving a score between 0 and 21, higher scores indicate higher levels of anxiety
  8. 4Post-concussion symptoms measured using the 13-item Rivermead scale giving a score between 0 and 52, higher scores indicate greater severity of post-concussion symptoms
  9. 5SF-12v2-based SF6D index scores calculated using weights from Brazier and Roberts [20]. SF-12v2-based SF6D index scores range between 0.350 (the ‘pits’) and 1.000 (full health)