In patients with fibromyalgia syndrome (FMS), the global impression of improvement is correlated with changes in clinical rating scale items or subscales assessing multiple symptom domains. In addition to pain reduction, factors that may contribute to perceptions of improvement among patients with FMS include improvement in fatigue, physical functioning, mood, and impact on daily living.
Hudson and associates examined pooled data from 4 randomized, double-blind, placebo-controlled studies of duloxetine(Drug information on duloxetine) in patients with FMS. The studies used several rating scales, including the Patient Global Impression of Improvement (PGI-I), to evaluate clinical domains identified as important by the Outcomes Measures for Rheumatoid Arthritis Clinical Trials (OMERACT). The investigators based their analysis on 7 patient-rated scales and 1 clinician-rated scale and examined how the scores from each domain correlated with the PGI-I.
Correlating most closely were changes in scores for pain, physical functioning, fatigue, and impact on daily living—domains also identified by OMERACT as most significant to quality of life. None of the variables in the emotional well-being domain (eg, motivation, depression) were highly correlated with the PGI-I.
The authors noted that the former domains may be important for outcome assessments in clinical trials and in the treatment of patients with FMS.
