Minimal difference in pain associated with change in quality of life in children with rheumatic disease

Objective. To establish the minimal change on a pain visual analog scale (VAS) associated with change in self-reported quality of life in pediatric rheumatology patients. Methods. Subjects were a cohort of 533 pediatric rheumatology patients in Toronto. Pain and perceived quality of life were measured at 2 consecutive visits to a clinic. Results. Among patients who rated quality of life at the second visit as "a little better" and "much better," the mean change in pain score on a 10-cm VAS was reduced by 0.82 and 1.45 cm, respectively. For those whose quality of life changed to "a little worse" and "much worse," the pain scores increased by 1.90 and 3.69 cm. Conclusion. Our results suggest that future studies of the assessment and treatment of pain in this population should aim for a minimum reduction in pain score of 0.82 cm on a 10-cm VAS to achieve clinical improvement in quality of life.