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Republished research from the BMJ
Red flags to screen for malignancy and fracture in patients with low back pain This is a summary of a paper that was published on bmj.com as BMJ 2013;347:f7095
STUDY QUESTION What are the best red flags to indicate the possibility of fracture or malignancy in patients presenting with low back pain in primary, secondary, or tertiary care? SUMMARY ANSWER Older age, prolonged corticosteroid use, severe trauma, and presence of a contusion or abrasion increase the likelihood of spinal fracture (likelihood was higher with multiple red flags); a history of malignancy increases the likelihood of spinal malignancy. SELECTION CRITERIA FOR STUDIES Medline, OldMedline, Embase, and CINAHL were searched from earliest available up to 1 October 2013. Primary diagnostic studies comparing red flags for fracture or malignancy to an acceptable reference standard in any language were included. Three independent reviewers extracted data from qualifying studies and assessed quality with QUADAS.
PRIMARY OUTCOME We generated diagnostic accuracy statistics and post-test probabilities for each red flag identified and matched these to guideline recommendations for the use of red flags involving the diagnosis of low back pain.
MAIN RESULTS We included 14 studies (eight from primary care, two from secondary care, four from tertiary care) evaluating 53 red flags; only five studies evaluated combinations of red flags. Pooling of data was not possible because of index test heterogeneity. Study quality items that were often inadequately covered or unclear were an acceptable delay between index and reference tests, partial verification, differential verification, reference standard blinding, reporting uninterpretable results, and explaining withdrawals. Point prevalence we used to calculate post-test probability was determined by extracting prevalence from a reduced set Red flags with highest probability for detection of fracture or malignancy in patients with low back pain Probability* (%) Pathology and red flag Fracture Prolonged use of corticosteroid Combination† Contusion/abrasion Malignancy History of malignancy
Setting
When absent
When present
Primary care
0.8
32.9
Primary care Emergency department
0.6 0.8
90.2 62.1
Primary care
0.1
32.5
*Probabilities presume prevalence of fracture is 1% in primary care, 5% in secondary and tertiary care; and prevalence of malignancy is 0.5% in primary care, 1.5% in secondary and tertiary care. †Any three of female, age >70, severe trauma, prolonged use of corticosteroids.
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of methodologically robust studies for fracture and cancer and by considering a value that could be readily applied in the clinical setting (fracture: 1% for primary care, 5% for secondary and tertiary care; malignancy: 0.5% for primary care, 1.5% for secondary and tertiary care). Many red flags in current guidelines provide virtually no change in probability of fracture. Example post-test probabilities are spinal tenderness (2%, 95% confidence interval 1% to 3%) and spasm (1%, 0% to 4%). The red flags with the highest post-test probability for detection of fracture were older age (9%, 95% confidence interval 3% to 25%), prolonged corticosteroid use (33%, 10% to 67%), severe trauma (11%, 8% to 16%), and presence of a contusion or abrasion (62%, 49% to 74%). The probability of spinal fracture was higher when multiple red flags were present (90%, 34% to 99%); but this approach is not endorsed in current guidelines. Many red flags in current guidelines provide little or virtually no change in probability of malignancy. Examples are unexplained weight loss (1%, 95% confidence interval 0% to 5%), insidious onset (1%, 0% to 1%), and failure to improve after one month (2%, 1% to 3%). The red flag with the highest post-test probability for detection of spinal malignancy was history of malignancy (33%, 22% to 46%).
BIAS, CONFOUNDING, AND OTHER REASONS FOR CAUTION In this review we graphically portray the post-test probability and 95% confidence intervals for investigated red flags. Our results enable clinicians to easily interpret the informativeness of red flags to screen for spinal fracture and malignancy. A limitation of this approach is that prevalence of fracture and malignancy varied considerably between studies (fracture: from 0.7% to 11.0%; malignancy: from 0% to 7.0%) and depended on study methods and setting. Therefore values for prevalence and post-test probability in our review might not generalise to every setting.
Aron Downie,1,2 Christopher M Williams,1 Nicholas Henschke,1,3 Mark J Hancock,4 Raymond W J G Ostelo,5 Henrica C W de Vet,6 Petra Macaskill,7 Les Irwig,8 Maurits W van Tulder,9 Bart W Koes,10 Christopher G Maher1 1
George Institute for Global Health, University of Sydney, Sydney, NSW, 2050, Australia 2 Faculty of Science, Macquarie University, Sydney, Australia 3 Institute of Public Health, University of Heidelberg, Germany 4 Faculty of Human Sciences, Macquarie University, Sydney, Australia 5 Department of Health Sciences, EMGO Institute for Health and Care Research, VU University, Amsterdam, Netherlands 6 Department of Epidemiology and Biostatistics, EMGO Institute for Health and Care Research, VU University Medical Centre, Amsterdam 7 Screening and Test Evaluation Program (STEP), School of Public Health, Sydney 8 School of Public Health, University of Sydney, Sydney, Australia 9 Department of Health Sciences, Faculty of Earth and Life Sciences, VU University, Amsterdam, Netherlands 10 Department of General Practice, Erasmus Medical Centre, Rotterdam, Netherlands Correspondence to: A Downie, George Institute for Global Health, University of Sydney, PO Box M201, Camperdown, Sydney, NSW, 2050, Australia;
[email protected]
To cite Downie A, Williams CM, Henschke N, et al. Br J Sports Med 2014;48:1518. Br J Sports Med 2014;48:1518. doi:10.1136/bjsports-2014-f7095rep
Downie A, et al. Br J Sports Med October 2014 Vol 48 No 20
Downloaded from http://bjsm.bmj.com/ on November 24, 2014 - Published by group.bmj.com
Red flags to screen for malignancy and fracture in patients with low back pain Aron Downie, Christopher M Williams, Nicholas Henschke, Mark J Hancock, Raymond W J G Ostelo, Henrica C W de Vet, Petra Macaskill, Les Irwig, Maurits W van Tulder, Bart W Koes and Christopher G Maher Br J Sports Med 2014 48: 1518
doi: 10.1136/bjsports-2014-f7095rep Updated information and services can be found at: http://bjsm.bmj.com/content/48/20/1518
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