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How common is imaging for low back pain in primary and emergency care? Systematic review and meta-analysis of over 4 million imaging requests across 21 years
  1. Aron Downie1,2,
  2. Mark Hancock3,
  3. Hazel Jenkins2,
  4. Rachelle Buchbinder4,5,
  5. Ian Harris6,
  6. Martin Underwood7,
  7. Stacy Goergen8,
  8. Chris G Maher1
  1. 1 Institute for Musculoskeletal Health, The University of Sydney, Sydney Medical School, School of Public Health, Sydney, New South Wales, Australia
  2. 2 Faculty of Science and Engineering, Macquarie University, Macquarie Park, New South Wales, Australia
  3. 3 Discipline of Physiotherapy, Medicine and Health Sciences, Macquarie University, Macquarie Park, New South Wales, Australia
  4. 4 Monash Department of Clinical Epidemiology at Cabrini Hospital, Cabrini Institute, Melbourne, Victoria, Australia
  5. 5 Department of Epidemiology and Preventive Medicine, School of Public Health and Preventive Medicine, Monash University, Victoria, Australia
  6. 6 South Western Sydney Clinical School, University of New South Wales, Sydney, New South Wales, Australia
  7. 7 Warwick Clinical Trials Unit, Health Sciences Research Institute, University of Warwick, Coventry, UK
  8. 8 School of Clinical Sciences, Monash University, Clayton, New South Wales, Australia
  1. Correspondence to Aron Downie, Institute for Musculoskeletal Health, Sydney School of Public Health, Faculty of Medicine and Health, The University of Sydney, Camperdown, NSW 2050, Australia; aron.downie{at}


Objectives To (1) estimate the proportion of patients seeking care for low back pain (LBP) who are imaged and (2) explore trends in the proportion of patients who received diagnostic imaging over time. We also examined the effect of study-level factors on estimates of imaging proportion.

Data sources Electronic searches of MEDLINE, Embase and CINAHL databases from January 1995 to December 2017.

Eligibility criteria for selecting studies Observational designs and controlled trials that reported imaging for patients presenting to primary care or emergency care for LBP. We assessed study quality and calculated pooled proportions by care setting and imaging type, with strength of evidence assessed using the GRADE system.

Results 45 studies were included. They represented 19 451 749 consultations for LBP that had resulted in 4 343 919 imaging requests/events over 21 years. Primary care: moderate quality evidence that simple imaging proportion was 16.3% (95% CI 12.6% to 21.1%) and complex imaging was 9.2% (95% CI 6.2% to 13.5%). For any imaging, the pooled proportion was 24.8% (95% CI 19.3%to 31.1%). Emergency care: moderate quality evidence that simple imaging proportion was 26.1% (95% CI 18.2% to 35.8%) and high-quality evidence that complex imaging proportion was 8.2% (95% CI 4.4% to 15.6%). For any imaging, the pooled proportion was 35.6% (95% CI 29.8% to 41.8%). Complex imaging increased from 7.4% (95% CI 5.7% to 9.6%) for imaging requested in 1995 to 11.4% (95% CI 9.6% to 13.5%) in 2015 (relative increase of 53.5%). Between-study variability in imaging proportions was only partially explained by study-level characteristics; there were insufficient data to comment on some prespecified study-level factors.

Summary/conclusion One in four patients who presented to primary care with LBP received imaging as did one in three who presented to the emergency department. The rate of complex imaging appears to have increased over 21 years despite guideline advice and education campaigns.

Trial registration number CRD42016041987.

  • lower back
  • diagnosis
  • MRI
  • radiography
  • primary care

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  • Contributors Conception and design: AD, MH, CGM and HJ. Analysis and interpretation of the data: AD, MH, HJ, CGM, MU and RB. Drafting of the article: AD, MH, HJ and CGM. All authors critically revised the article for important intellectual content and approved the final article. Statistical expertise: AD, MH and CGM. Administrative, technical or logistic support: CGM and MH. Extraction and assembly of data: AD, HJ, MH and CGM. The corresponding author (AD) attests that all listed authors meet authorship criteria and that no others meeting the criteria have been omitted. AD is guarantor.

  • Funding The authors have not declared a specific grant for this research from any funding agency in the public, commercial or not-for-profit sectors.

  • Competing interests For support outside the submitted work MU declares: funding by UK National Institute for Health Research and Arthritis Research UK, SERCO Ltd, personal fees from UK National Institute for Health and Care Excellence, personal fees from UK National Institute for Health Research and other from Clinvivo Ltd.

  • Provenance and peer review Not commissioned; externally peer reviewed.

  • Data sharing statement No additional available.

  • Patient consent for publication Not required.