Aim: To investigate whether the effect of educational reminder messages for knee and lumbar spine radiographs varied over a 12 month period.
Materials and methods: In a previous randomized, controlled trial, educational reminder messages attached to x-ray reports were shown to be effective in reducing the number of radiograph requests by general practitioners for knee and lumbar spine radiographs. In this study, all radiology departments from the previous trial were asked for monthly referral records for the 12 month intervention period for knee and lumbar spine radiographs for each general practice. Poisson regression was used to test for a change over time in the number of referrals between control and intervention practices.
Results: Data were obtained for 66% of the general practices in the main trial. The number of referrals for both knee and lumbar spine radiographs remained consistently and statistically significantly lower in the educational reminder messages group compared with the control group (relative risk=0.65 and 0.64, respectively). There was no evidence that this difference increased or decreased throughout the 12 month period.
Conclusions: The effect of educational reminder messages was produced as soon as the intervention was delivered and maintained throughout the intervention period. There was no evidence of the effect of the intervention wearing off.