Red flags to screen for malignancy and fracture in patients with low back pain: systematic review

Journal Club 31/1/14 Robina Town Medical Centre, Summary by Jane Smith

Low Back Pain

Low back pain is a common presentation, very variable in it’s presentation, and  often investigated without leading to any change of management or improved prognosis.

Guidelines make recommendations about investigations based on whether “red flags” are present or not. Sometimes guideline recommendations to order imaging is in conflict with our clinical impression or the patients wishes.

It is of critical importance to know how useful red flags are to identify serious pathology or avoid missing it.

Research Paper: Red flags to screen for malignancy and fracture in patients with low back pain: systematic review

Downie A,  Williams CM,  Henschke N, Hancock MJ, et al

BMJ 2013;347:f7095 doi: 10.1136

This paper was chosen because it is a systematic review about how valid and useful guidelines red flags are to identify serious pathology (fracture or malignancy).

Discussion centred around significant values of likelihood ratios(LR): namely 10X for LR Positive, and conversely 0.1 for a LR negative.

The paper showed that many red flags used in guidelines do not reach anywhere near expected levels of significance.

The best performing red flags were :

For malignancy

  • a history of cancer with LR+ of 35x and LR –ve 0.1.

For Fracture

  • Polonged corticosteroid use  with LR+ of 48x, and
  • Presence of contusion or abarasion LR+ve = 31
  • Age >64 and female LR+ 15x
  • Age >75 and female LR+ve 16x
  • Major or minor trauma LR+ = 13x

Even these red flags found to be statistically significant had little advantage over clincal judgement in terms of predictiong probability. This paper suggests that current guidelines promote over investigation, because many red flags listed are not strong predictors of any serious pathology.

Prevalences given in the paper sugest that In primary care, about 1% of patients presenting with low back pain will have a fractue and 0.5% malignancy, but the odds increase in the secondary care setting to more than 5 % for fracture and 1.5%  for malignancy

Take home message:

We need to use clinical judgement when implementing low back pain guidelines to avoid over investigating

To read the full article, click on the link below

Low back pain red flags