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.
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.
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.
Severe CRPS outcome is rare, but a majority of patients has persistent impairments at 2 or more years since onset.
Departments of *Medical Informatics and Epidemiology and Biostatistics
†Pain Treatment, Erasmus University Medical Center, Rotterdam, The Netherlands
Disclosure of Funding: This study was performed within TREND (Trauma RElated Neuronal Dysfunction), a knowledge consortium that integrates research on Complex Regional Pain Syndrome type 1. The project is supported by a Dutch Government grant (BSIK03016). M. de Mos and B.H.Ch. Stricker have no financial or other types of conflicts of interest. M.C.J.M. Sturkenboom has been involved as a project leader in analyses contracted by various pharmaceutical companies and received unconditional research grants from Pfizer; Merck; Johnson & Johnson; Amgen; Roche; and Altana; none of which are related to the subject of this study. She has been consultant to Pfizer, Servier, Celgene, Novartis, and Lundbeck on issues not related to this study. J.P. Dieleman: has been involved in analyses contracted by various pharmaceutical companies and received unconditional research grants from Pfizer; Merck; Johnson & Johnson; Amgen; Roche; and Altana; none of which are related to the subject of this study. F.J.P.M. Huygen: received unrestricted research grants from Pfizer; Merck, Sharp, and Dohme; Mundipharma; Medtronic; and Janssen-Cilag; none of which are related to this study.
Reprints: Marissa de Mos, MD, Department of Medical Informatics, Erasmus Medical Center, Room 2157, Dr. Molewaterplein 50, 3015 GE Rotterdam, The Netherlands (e-mail: email@example.com).
Received for publication July 2, 2008; revised February 11, 2009; accepted February 13, 2009