Comparison of multiple against single pain intensity measurements in complex regional pain syndrome type I: Analysis of 54 patients

Objective: To describe the comparison of multiple and single pain ratings in patients with complex regional pain syndrome type I (CRPS I). Design: Correlation, agreement, and reliability analyses were performed between the average pain intensity measured 3 times a day over a course of 4 days and one single pain rating (designated the "recalled average" pain, as assessed by the patient) before treatment and at 1-, 3-, and 6-month periods after treatment. Patients: The patient population consisted of 54 patients with CRPS I in a randomized trial. Results: The results show that both measurements correlate and have excellent agreement. Furthermore, both ratings measure significant pain reduction after treatment; "recalled average" pain, however, reflects greater change in pain intensity. Conclusions: In patients with CRPS I a single pain rating is an accurate predictor of the average pain measured by a multiple pain-rating test. Moreover, both assessments are accurate enough to determine changes in pain over time with an effective treatment.