Current treatments for low back pain have minor effects. A research priority is to identify patient characteristics associated with larger effects for particular interventions. This study aimed to identify simple clinical characteristics of patients with chronic low back pain who would benefit more from either motor control exercises or graded activity. 172 patients presenting with chronic low back pain were placed in the trial. The treatment was comprised of 12 initial exercise sessions over an 8-week period and booster sessions at 4 and 10 months after randomization. The putative effect modifiers (psychosocial features, physical activity level, walking tolerance and self-reported signs of clinical instability) were measured at baseline. Measures of pain and function (both measured on a 0-10 scale) were taken at baseline, 2, 6 and 12 months by a blinded assessor. The study found self-reported clinical instability was a statistically significant and clinically important modifier of treatment response for 12 month function (interaction: 2.72; 95% CI 1.39 to 4.06). Individuals with high scores on the clinical instability questionnaire (≥9) did 0.85 points better with motor control whereas people who had low scores (<9) did 1.93 points better with graded activity. Most other effect modifiers investigated did not appear to be useful in identifying preferential response to exercise type.
The study found that a simple 15-item questionnaire of features thought to be indications of clinical instability can identify patients who respond best to either motor control exercise or graded activity.