A cross-sectional cohort survey in 2100 patients with painful diabetic neuropathy and postherpetic neuralgia: Differences in demographic data and sensory symptoms

Patients with neuropathic pain syndromes are heterogeneous. They present with a variety of sensory symptoms and pain qualities. The knowledge of these data and etiology-specific differences is important to optimize clinical trial design and to develop more effective drugs. This investigation uses epidemiological and clinical data on the symptomatology of 2 100 patients with painful diabetic neuropathy (DPN) and postherpetic neuralgia (PHN) from a cross-sectional survey (painDETEM to (1) describe characteristic epidemiological differences, (2) analyse typical patterns of sensory symptoms in both cohorts and (3) determine whether questionnaires can capture these characteristics. PHN patients suffer more often from clinically relevant sensory disturbances although the average pain intensity is only marginally higher. This difference is particularly obvious with dynamic mechanical allodynia which is present in half of the PHN patients and in 18% of the DPN patients. Thermal hyperalgesia occurs twice as often in PHN. Numbness is described more often in DPN. Age has no influence on sensory symptoms in both entities. A hierarchical Cluster analysis revealed five distinct subgroups of patients showing a characteristic sensory profile, a typical constellation and combination of neuropathic symptoms. All Subgroups occur in relevant numbers in both entities but the frequencies differ between PHN and DPN. Since sensory symptoms likely translate into pain-generating mechanisms enrichment for potential treatment responders might be possible in clinical trials by assessing the sensory profiles. Patient-Reported Outcomes can be used to obtain a precise sensory characterization of each patient. (C) 2009 International Association for the Study of Pain. Published by Elsevier B.V. All rights reserved.