Finding risk factors to predict which patients will move from acute pain to chronic pain is the subject of much research and debate. As you pointed out, finding a reliable way to do this may help with management and prevention of chronic low back pain. The result could be a huge savings of pain, suffering, and financial cost for millions of people.
So far, there isn’t a single approach being used by everyone. In 2006, a study was published by two American researchers (Von Korff and Miglioretti) using the Chronic Pain Grades to predict pain a year later. This tool doesn’t rely just on how long patients have had pain to define chronic pain. Intensity and influence on function are also considered.
The methods used by the American group were retested in the United Kingdom (U.K.). Patients with acute low back pain from five different general medical practices in North Staffordshire were included. Outcomes after one year were compared with measures of pain and depression used to predict chronic pain.
They found the Chronic Pain Grade could be used by different populations in different health care systems. However, there were some major differences in some of the results.
The British researchers rechecked their cut off scores to make sure they used the same levels as the American group. They weren’t sure the same risk scores could be used as predictive or prognostic factors among different groups. For example, a score above 18 suggested an increased risk of having chronic pain 12 months later.
They concluded the American cut-off points weren’t the problem. It was more likely the timing of when the testing was done. The sooner the test was done after onset of back pain, the more likely the test scores would predict chronic back pain. This led the researchers to suggest using the Chronic Pain Grade for patients who see their physicians but don’t get better and come back for follow-up care.