Pain has a major impact in chronic rheumatic diseases. Pain has been much less studied in systemic sclerosis (SSc) than in rheumatoid arthritis (RA), in which it is systematically assessed and is a major outcome measures both for trials and in routine care. Our objectives were to measure and characterise pain and its management in patients with (SSc), and to compare these aspects between SSc and RA patients.
A prospective study was carried out over a nine-month period in 3 universitary medical departments: consecutive inpatients with SSc or RA referred for routine assessment of disease activity were examined and asked to complete self-reported pain (MPQ, DN4, BPI), sleep, psychological (PCS, SOPA, Beck, HADs) and quality of life (SF12) questionnaires. Patients referred for severe or end-stage organ involvements were excluded.
We included 159 patients: 82 SSc patients (85% women, 59±12 years of age, 56% with limited cutaneous and 44% with diffuse SSc, relatively severe as reflected by 45% of patients fulfilling Medsger’s classes 3-4, SSc-HAQ 1.5±1.0) and 67 RA (68% women, 55±14 years of age, mean DAS 4.3±1.6, HAQ 1.9±1.0). Pain was significantly less frequent (55%) and less intense (VAS 3.9 ± 2.6) in SSc patients than in RA patients (75%, 5.3±2.1, P<0.001). Significant differences in type of pain were found between SSc and RA, with pain being more frequently generalised, (26% vs 20%, p=0.01), more frequently located in the skin (14% vs 1.3%, p<0.001) or muscle (9% vs 2.6, p=0.03) in SSc patients. A neuropathic pain component was observed in 40% of SSc vs 32.8% of RA patients (p<0.01), and pain related to synovitis and tenosynovitis was found in 25 % of SSc and in 78% of RA patients (p<0.001). Pain related to Raynaud’s phenomenon was found only in SSc patients (N=25), with mild pain intensity. The MPQ questionnaire subscales demonstrated significant differences between SSc and RA respectively, for both sensory (6.8±6.6 vs 10.8±6.9) and affective dimensions (2.7±3.1 vs 5.4±4.3). Even with adjustment for pain level, pain had a lower impact in SSc than in RA (BPI questionnaire) on general activity (p<0.001), mood (p<0.01), walking capacity (p<0.001), usual work (p<0.001), relationships with others (p<0.001) and enjoyment of life (p<0.05). This was not related to a higher psychological distress since we found similar levels of anxiety and depression in SSc and RA, but was significantly correlated to the presence of joint pain. Pain coping strategies did not found differences in catastrophizing (PCS), but demonstrated higher scores for emotion and medication in RA patients (SOPA). No difference was observed between SSc and RA in analgesic prescriptions, regardless of the type of pain, except for acetaminophen (20% vs 27%, p=0.02)
In SSc, pain appears less intense, less frequent and more diffuse than in RA, with a limited impact, and does not represent a major severity symptom, conversely to RA. However, a neuropathic component can be more frequently found in SSc,. Furthermore, in SSc, when there is a joint component, sensory and affective pain dimensions are increased, with high impact and high medication demands, reaching the levels observed in RA patients.
Disclosure: S. Perrot, None; P. Dieude, None; Y. Allanore, Pfizer Inc, 2, Actelion Pharmaceuticals US, 2, Actelion Pharmaceuticals US .