What is a meaningful pain reduction in patients with complex regional pain syndrome type 1?
OBJECTIVE
To investigate the degree of pain reduction in patients with complex regional pain syndrome type 1 (CRPS 1) that can be defined as "successful."


METHODS
All patients rated their pain on a visual analog scale (VAS; 0-10) before treatment and on three occasions after treatment, at 6 months, 1 year, and 2 years. Patients also rated a Global Perceived Effect (GPE) for their pain relief at the same time periods. The GPE items were classified as "successful" or "unsuccessful." The mean absolute and relative pain reduction (using the VAS) was calculated for both "successful" and "unsuccessful" GPE classifications for each time period. Sensitivity and specificity analyses were performed.


METHODS
Sixty-one patients with CRPS 1.


RESULTS
The patients defined a relative pain reduction of 58% (SD, 23.4) or more as "successful," whereas in "successful" and "unsuccessful" patient groups the pain was reduced significantly on the VAS. Furthermore, sensitivity and specificity analyses showed that a cut-off point of 50% relative pain reduction and a 3-cm absolute pain reduction on the VAS have the highest likelihood that patients will report their treatment "successful" on the GPE.


CONCLUSIONS
Relative pain reduction of 50% or more and an absolute pain reduction of at least 3 cm on the VAS are accurate in predicting a successful pain reduction after a given treatment.
Forouzanfar
Tymour
T
Pain Management and Research Center, University Hospital Maastricht, P.O. Box 5800, 6202 AZ Maastricht, The Netherlands. TFOR@sane.azm.nl
Weber
Wilhelm E J
WE
Kemler
Marius
M
van Kleef
Maarten
M
D000328:Adult; D004599:Electric Stimulation Therapy / Q000379:methods*; D005260:Female; D005500:Follow-Up Studies; D006801:Humans; D008297:Male; D010147:Pain Measurement / Q000379:methods; D012019:Reflex Sympathetic Dystrophy / Q000175:diagnosis* / Q000628:therapy*; D015203:Reproducibility of Results; D012680:Sensitivity and Specificity; D016896:Treatment Outcome