Results from studies
| Study | Comparison | Imaging type | Events, n/N | Outcome measure, % of patients or rate per 1 000 | Risk ratio (95% CI)*† | Effect (95% CI) with adjustment for clustering reported in original study | ||
|---|---|---|---|---|---|---|---|---|
| Intervention group | Control group | Intervention group | Control group | |||||
| Cluster RCT | ||||||||
| Dichotomous outcomes | ||||||||
| Dey et al.19 | Practitioner education v. no intervention | Lumbar spine radiography | 158/1 049 | 156/1 138 | 15.1% | 13.7% | 1.1 (0.9 to 1.4) | Risk difference‡ 1.4% (−4.1% to 6.8%) |
| Schectman et al.20 | Audit + feedback v. no intervention | Lumbar spine radiography | 112/588 | 98/544 | 19.0% | 18.0% | 1.1 (0.8 to 1.4) | Not reported |
| Lumbar spine CT or MRI | 33/588 | 39/544 | 5.6% | 7.1% | 0.8 (0.5 to 1.2) | Not reported | ||
| French et al.18 | Practitioner education v. guideline dissemination | Lumbar spine radiography | 643/77 716 | 768/75 226 | 8.3 per 1 000 | 10.2 per 1 000 | 0.8 (0.7 to 0.9) | IRR† 0.8 (0.6 to 1.1) |
| Lumbar spine CT | 474/77 716 | 496/75 226 | 6.1 per 1 000 | 6.6 per 1 000 | 0.9 (0.8 to 1.1) | IRR† 0.9 (0.7 to 1.3) | ||
| Eccles et al.7 | Audit + feedback v. guideline dissemination | Lumbar spine radiography | NR | NR | 6.0 per 1 000 | 6.8 per 1 000 | 0.9 (NC) | Absolute change‡ in rate −0.07 (−1.3 to 0.9) |
| Reminders v. guideline dissemination | Lumbar spine radiography | NR | NR | 5.1 per 1 000 | 6.8 per 1 000 | 0.8 (NC) | Absolute change‡ in rate −1.5 (−2.5 to −0.6) | |
| Reminders + audit + feedback v. guideline dissemination | Lumbar spine radiography | NR | NR | 5.2 per 1 000 | 6.8 per 1 000 | 0.8 (NC) | No effect (no numeric data reported) | |
| Continuous outcomes | ||||||||
| Kerry et al.21 | Audit + feedback v. no intervention | – | – | – | NR | NR | – | Percentage mean difference§ in change score: −20% (3% to 37%) |
| Study | Intervention | Mean no. of referrals per month before intervention | Absolute change in referrals in first month after intervention (95% CI)§¶ | Change in slope of linear trend line from before to after intervention (95% CI)‡¶ | ||||
| Interrupted time series | ||||||||
| Matowe et al.17 | Guideline dissemination | 147.7 | −7.7 (−24.7 to 40.2) | 0.0 (−1.8 to 1.8) | ||||
| Baker et al.24 | Clinical decision support | 120.3 | −44.3 (−48.7 to −39.9) | 2.0 (−2.1 to 6.1) | ||||
Note: CI = confidence interval, CT = computed tomography, IRR = incident rate ratio, MRI = magnetic resonance imaging, NC = not calculated because of lack of data presented in original study, NR = not reported, RCT = randomized controlled trial.
↵* Analysis based on extracted raw data, not adjusted for clustering.
↵† Value less than 1 represents a decrease in imaging in the intervention group compared with the control.
↵§ Negative value represents a decrease in imaging in the intervention group compared with the control.
↵‡ Positive value indicates a sustained effect of the intervention over time.
↵¶ Time series regression analysis.