This is not to say that 80% of people with low back pain should raise suspicion of serious pathology. Jeez.
Rather, these are signs or symptoms that have historically been considered relevant and should therefore pique the clinician's interest, prompting them to sit up and ask more questions.
Most have limited diagnostic utility in isolation.
Take sleep disturbance, for example. On its own, without context, it is very common and a rather blunt indicator.
80% of back pain patients have at least 1 red flag.
That doesn't mean 80% need an MRI.
Here's the take home points from a recent GP seminar I spoke on 🧵