Chronic pain in Parkinson's disease: the cross-sectional French DoPaMiP survey.

Pain is a frequent, but poorly studied symptom of Parkinson's disease (PD). DoPaMiP survey aimed to assess the prevalence of chronic pain in PD, to describe PD patients with chronic pain, and to record analgesic consumption. About 450 parkinsonian patients underwent structured standardized clinical examination and completed self-reported questionnaires in a cross sectional survey. Pains related or unrelated to PD were identified according to predefined criteria. About 98 patients with other chronic disorders than PD were examined to assess if pain was more frequent in PD than in this population. Two thirds parkinsonian patients (278 of 450) had chronic pain. Twenty-five patients with non-chronic pain (<3-month duration) were excluded from subsequent analysis. Twenty six percent (111 of 425) parkinsonian patients had pain unrelated to PD ("non-PD-pain", caused mainly by osteoarthritis), while 39.3% (167 of 425) had chronic pain related to PD ("PD-pain"). In this last group, PD was the sole cause of pain in 103 and indirectly aggravated pain of another origin (mainly osteoarthritis) in 64. Parkinsonian patients with "PD-pain" were younger at PD onset, had more motor complications, more severe depressive symptoms than those without pain or with "non-PD pain." "PD-pain" was more intense (P = 0.03), but was less frequently reported to doctors (P = 0.02), and was associated with less frequent analgesic consumption than "non-PD-pain." Pain was twice more frequent in PD patients than in patients without PD after adjustment for osteo-articular comorbidities (OR = 1.9; 95% CI 1.2-3.2). Chronic pain is frequent but underreported in PD. Awareness of this problem should be increased and the assessment of analgesic strategies improved.