Improvement Threshold Defines Low Back Pain Success
Fifty percent improvement on Modified Oswestry disability index confirmed as valid measure
THURSDAY, Dec. 17 (HealthDay News) -- In patients with low back pain, a successful outcome may be defined as at least a 50 percent improvement on the Modified Oswestry disability index, according to a study in the Dec. 1 issue of Spine.
Julie M. Fritz, Ph.D., of the University of Utah in Salt Lake City, and colleagues studied 243 subjects (mean age, 37.2 years) who underwent four weeks of physical therapy and completed a 15-point global rating of change.
The researchers found that the mean Modified Oswestry disability index change was 43.1 percent, and that 109 subjects (44.9 percent) achieved an improvement of at least 50 percent. When compared with success based on the global rating of change, they also found that the 50 percent Modified Oswestry disability index improvement threshold had high sensitivity and specificity (0.84 and 0.89, respectively) and that no other thresholds had greater accuracy.
"Reporting the percentages of subjects achieving a threshold level of improvement can improve the interpretability of clinical research," the authors conclude. "Depending on the context of specific studies, a threshold of 50 percent improvement on the Modified Oswestry disability index may be a valid measure of determining how many patients achieved 'success' with a particular treatment."