Outcome of the complex regional pain syndrome.

Objectives: The outcome of complex regional pain syndrome (CRPS) is relatively unknown. High disease resolution rates have been reported, but also long-lasting impairments in many patients. This study aims to assess CRPS outcome in a population-based cohort of CRPS patients.

Methods: CRPS patients were retrospectively identified (1996 to 2005) in a Dutch general practitioners database, the integrated primary care information project, and included if at onset (ie, in the past) they had complied with the International Association for the Study of Pain (IASP) diagnostic criteria. The disease status at minimum of 2 years since onset was assessed during visits using questionnaires, interviews, and physical examination. Symptoms and signs were compared with reference patients with an identical past injury but without CRPS. Actual fulfillment of the IASP criteria, treatment status, self-reported recovery, and working status were recorded. Moreover, to identify the potential prognostic factors, baseline patient characteristics were compared across subgroups according to the CRPS outcome. These subgroups were derived by cluster analysis on actual symptoms and signs.

Results: One hundred and two CRPS patients were assessed at on average 5.8 years (range: 2.1 to 10.8) since onset. CRPS patients displayed higher symptom and sign prevalences in all categories (sensory, vasomotor, sudomotor, and motor/trophic) than controls. Sixteen percent (95% CI: 9-22) reported the CRPS as still progressive, whereas 31% (95% CI: 19-43) were incapable of working. Patients in the poorest outcome cluster more often had their upper extremity affected, event other than a fracture, and cold CRPS.

Discussion: Severe CRPS outcome is rare, but a majority of patients has persistent impairments at 2 or more years since onset.