Abstract: Eight studies set in primary (four), secondary (one) and tertiary care (accident and emergency = three) were included in the review. Overall, the risk of bias of studies was moderate with high risk of selection and verification bias the predominant flaws. Reporting of index and reference tests was poor. The prevalence of vertebral fracture in accident and emergency settings ranged from 6.5% to 11% and in primary care from 0.7% to 4.5%. There were 29 groups of index tests investigated however, only two featured in more than two studies. Descriptive analyses revealed that three red flags in primary care were potentially useful with meaningful positive likelihood ratios (LR+) but mostly imprecise estimates (significant trauma, older age, corticosteroid use; LR+ point estimate ranging 3.42 to 12.85, 3.69 to 9.39, 3.97 to 48.50 respectively). One red flag in tertiary care appeared informative (contusion/abrasion; LR+ 31.09, 95% CI 18.25 to 52.96). The results of combined tests appeared more informative than individual red flags with LR+ estimates generally greater in magnitude and precision. The available evidence does not support the use of many red flags to specifically screen for vertebral fracture in patients presenting for LBP. Based on evidence from single studies, few individual red flags appear informative as most have poor diagnostic accuracy as indicated by imprecise estimates of likelihood ratios. When combinations of red flags were used the performance appeared to improve. From the limited evidence, the findings give rise to a weak recommendation that a combination of a small subset of red flags may be useful to screen for vertebral fracture. It should also be noted that many red flags have high false positive rates; and if acted upon uncritically there would be consequences for the cost of management and outcomes of patients with LBP. Further research should focus on appropriate sets of red flags and adequate reporting of both index and reference tests.

Plain-language summary: Eight studies including several thousand patients described 29 different questions and physical exam tests that have been used to look for spinal fractures.  Most of the 29 were not accurate.  The best four questions asked about use of steroids (which can cause weak bones), the patient’s age (age above 74 increases the risk of fractures) and recent trauma such as a fall.  Using a combination of the best questions appears to improve the accuracy.  For example, women above age 74 are more likely to have a fracture when they come to the physician complaining of back pain.  In the emergency room, the best indication of a spinal fracture was a bruise or scrape on the painful area of the back. Fractures are rare and generally do not require emergency treatment, even if red flags exist clinicians and patients can watch and wait.  During the waiting period, patients should avoid treatments like exercise and manipulation that are not recommended for spinal fractures. The worst effects of low quality red flag screening are overtreatment and undertreatment.  If the tests are not accurate, patients without a fracture may get an x-ray or CT scan that they don’t need—unnecessary exposure to x-rays, extra worry for the patient and extra cost.  At the other extreme (and much less common), it might be possible to miss a real fracture, and cause the patient to have extra time without the best treatment. Most of the studies were of low or moderate quality, so more research is needed to identify the best combination of questions and examination methods.