Does early imaging influence management and improve outcome in patients with low back pain? A pragmatic randomised controlled trial.

OBJECTIVES: To establish whether the early use of sophisticated imaging techniques influences the clinical management and outcome of patients with low back pain (LBP) and whether it is cost-effective.

DESIGN: A pragmatic multicentre randomised controlled trial using a standard two parallel group approach incorporating an economic evaluation. For a subgroup of trial participants, a controlled 'before and after' approach was used to assess the impact of 'early imaging' on clinicians' diagnostic and therapeutic confidence.

SETTING AND PARTICIPANTS: A total of 782 participants who had been referred by their general practitioner to a consultant orthopaedic specialist or neurosurgeon because of symptomatic lumbar spine disorders. The study included 14 hospitals in Scotland and one in England over a 24-month period.

RESULTS: Participants in both groups reported an improvement in health status at 8 and 24 months with the 'early imaging' group having statistically significantly better outcome. Other than the proportion of participants receiving imaging (90% versus 30%), there were few differences between the groups in the management received throughout the 24-month follow-up. The total number of outpatient consultations in the two groups was similar although more people in the 'early imaging' group had return outpatient appointments during the 8-month follow-up. Clinicians' diagnostic confidence, between trial entry and follow-up, increased significantly for both groups with a greater increase in the 'early imaging' group. The cost of imaging was the main determinant of the difference in total costs between the groups and it was estimated that 'early imaging' could provide an additional 0.07 quality-adjusted life-years (QALYs), at an additional average cost of 61 British pounds over the 24-month follow-up. Using non-imputed costs and QALYs but adjusted for baseline differences in EQ-5D score, the mean incremental cost per QALY of 'early imaging' was 870 British pounds. The results were sensitive to the costs of imaging and the confidence intervals surrounding estimates of average costs and QALYs.

CONCLUSIONS: The early use of sophisticated imaging does not appear to affect management overall but does result in a slight improvement in clinical outcome at an estimated cost of 870 British pounds per QALY. Imaging was associated with an increase in clinicians' diagnostic confidence, particularly for non-specialists. Further research is required to determine if more rapid referral to sophisticated imaging and secondary care is important in the acute episode and whether the use of imaging would be more beneficial for particular categories of LBP.