A cross-sectional survey of 3035 patients with fibromyalgia: Subgroups of patients with typical comorbidities and sensory symptom profiles

Objectives. Patients with FM are heterogeneous. They present with a variety of pain qualities, sensory abnormalities and additional comorbidities. The aim was to identify clinically distinguishable subgroups of patients. Methods. This investigation uses epidemiological and clinical data of 3035 FM patients from a cross-sectional survey (painDETECT) to (i) describe characteristic epidemiological data and comorbidities and (ii) detect subgroups of patients with typical patterns of sensory symptoms and comorbidities. Results. Clinically relevant sensory abnormalities (strongly, very strongly present) included pressure pain (58%), prickling (33%), burning (30%) and thermal hypersensitivity (24%). Pain attacks were complained by 40% of patients. Moderate to severe comorbid depression occurred in 66% of patients. Only ~30% of the patients had optimal sleep. A hierarchical cluster analysis using descriptors of sensory abnormalities as well as the extent of comorbidities revealed five distinct subgroups of patients showing a characteristic clinical profile. Four subgroups of patients suffer from severe sensory disturbances in various combinations but lack pronounced comorbidities. In one subgroup, however, severe comorbidities dominate the clinical picture. Differences in pathophysiological mechanisms of pain generation can be attributed to each subgroup. Conclusions. The results of this study indicate that FM patients can be classified on the basis of their sensory symptoms and comorbidities by the use of a patient-reported questionnaire. Subgrouping of patients with FM may be used for future research and to tailor optimal treatment strategies for the appropriate patient.