Author: Shaikh MF, Shenker NG
Title: What happens to patients with complex regional pain syndrome of greater than 12 months' duration?
Source: 27th Annual General Meeting of the British Society for Rheumatology (BSR) held jointly with the 2010 Spring Meeting of the British Health Professionals in Rheumatology (BHPR) (Birmingham, UK: April 21, 2010)
Background: Complex Regional Pain Syndrome, CRPS, is recognized to be a common debilitating painful condition. CRPS persisting beyond 12 months is considered a chronic intractable condition which profoundly impacts on quality of life, activities of daily living and the ability to sustain employment. Standard treatments include analgesia, education, physiotherapy and desensitization. What happens to such patients in Addenbrooke's CRPS clinic? It is important to know this baseline level of pain and functioning prior to recruiting to n-of-1 cohort studies, as recommended by MRC Guidance.
Methods: A service evaluation of 21 patients with CRPS presenting to the Rheumatology Department in 2007-9 with a diagnosis of CRPS (IASP criteria) was performed. Demographic data and clinical outcomes were collected using the Brief Pain Inventory (BPI), Human Activity Profile (HAP, maximal and adjusted scores), Upper and Lower Extremity Functioning Indices (UEFI/LEFI). These were repeated three times over a 12-month period on average. The minimum statistically significant changes are HAP maximum 8, adjusted 7 and 9 for UEFI and LEFI. Only patients with CRPS for over a year were selected. Patients underwent a rehabilitation programme comprising optimal analgesia, education, physiotherapy and desensitization.
Results: 21 patients were formally assessed and followed up for 6-18 months. 13 patients fulfilled IASP research criteria for CRPS, 5 fulfilled diagnostic criteria and 3 had persistent unexplained limb pain. 20/21 (95%) were female with an average age of 40.4 years (21-58 years). The average duration of symptoms at the time of assessment was 67.6 months (25-384 months). The average length of time to diagnosis was 12.9 months (2-36 months). Affected sites were upper limb (11), lower limb (6) both upper and lower limb (4); 1 patient had neural damage (CRPS type 2). Maximum pain scores decreased from baseline (8.1) compared with 12-18 month follow-up (7.2) by 11 %. Average pain scores reduced by 16% (6.7 to 5.6). Patients reported 47% more pain relief from their analgesia (34 to 50). Average effect of pain on patients' life decreased by 19% (6.9 to 5.6). HAP maximum improved from 59.5 at baseline to 72.8 at 12-18 months and adjusted scores improved from 38.1 to 50.5. UEFI increased from 24.7 to 36.1 and LEFI from 31.9 to 43.1. All these improvements in activity and functioning are greater than the minimal change scores indicating modest, but significant improvements. 2/21 (9.5%) patients returned to employment. Those working continued to do so.
Conclusions: Patients with chronic CRPS have only modest benefits from a rehabilitation approach. More innovative treatments are needed. The 12.9 month delay in diagnosis may have contributed to chronicity in this cohort. More awareness of CRPS is needed and this needs to be studied in patients with early disease. Understanding the baseline fluctuations in patients with chronic CRPS allows n-of-1 interventions to be effectively evaluated.
Author Affiliation: Rheumatology Research Unit, Addenbrooke's Hospital, Cambridge, UK