Authors' reply to the comment by Pazzaglia et al

Abstract

Since the aetiologies of neuropathic pain are most often degenerative or age related, it is not surprising that these conditions are more common in the elderly (Ahmad and Goucke, 2002; Pickering and Capriz-Ribière, 2008). Neuropathic pain occurs and persists in a heterogeneous group of aetiologically different diseases, with various physio-pathological mechanisms (Cruccu and Truini, 2009; Baron et al., 2012). Patients with neuropathic pain present with various pain-related sensory abnormalities (Baron et al., 2012). Subgrouping patients with neuropathic pain on the basis of individual sensory profiles could guide the choice of pharmacological agents to be proposed to each patient (Bouhassira et al., 2004; Cruccu and Truini, 2009; Baron et al., 2012). We appreciate Pazzaglia et al.'s interest in our study on the characteristics of neuropathic pain in a population of sub-Saharan African elderly, followed for chronic pain of musculoskeletal origin (Lekpa et al., 2013). In this study, we choose to use the neuropathic pain diagnostic questionnaire DN4 (Bouhassira et al., 2005) instead of other validated instruments. Apart from its good discriminative properties for the identification of neuropathic pain, the DN4 questionnaire was easy to use, especially in our sample of elderly patients with a low level of education. Thus, we were able to show through this study that: (1) neuropathic pain existed in African elderly; (2) female gender, low educational status, manual professions, unemployment and diabetes mellitus were significantly associated with the presence of neuropathic pain; (3) chronic spine diseases and painful diabetic peripheral neuropathy are the main causes of neuropathic pain in our sample; and (4) neuropathic pain were neglected by physicians with a low rate of prescription drugs directed against neuropathic pain (Lekpa et al., 2013). In his comments, Pazzaglia et al. presented the methodology and results of a multicentre study they conducted among Italian elderly over 65 years, with peripheral neuropathy (Pazzaglia et al., 2013). The methodology used in our study was different from that used by these authors (musculoskeletal pain vs. peripheral neuropathy). Despite this difference, the results are broadly comparable. Indeed, these authors showed that (Pazzaglia et al., 2013): (1) neuropathic pain are also common in elderly; (2) the aetiologies are numerous; (3) the clinical profile or sensory profile, assessed with the Neuropathic Pain Symptom Inventory (NPSI) (Bouhassira et al., 2004), varies depending on the aetiology; and (4) also the low rate of prescription drugs targeting neuropathic pain. The use of NPSI (Bouhassira et al., 2004) would not have changed the results obtained in our study. However, it would have provided important additional information. We could have had a more accurate assessment of the clinical profile of our patients, differentiating subtypes of neuropathic pain. Indeed, the NPSI was developed and validated for the assessment of different symptoms of neuropathic pain. It is also a simple and easy-to-use instrument for daily practice and clinical studies. The NPSI allows discrimination and quantification of five distinct clinically relevant dimensions of neuropathic pain: burning (superficial) spontaneous pain, pressing (deep) spontaneous pain, paroxysmal pain, evoked pain and paraesthesia/dysaesthesia. One important feature of the NPSI is its sensitivity to treatment effects (Bouhassira et al., 2004). Subgrouping neuropathic pain in our study might have permitted us to make assumptions about the appropriate type of drug to offer to each of our patients, according to the sensory profile of the neuropathic pain presented by each patient, as suggested by Bouhassira et al. (2004), but it remains to be confirmed in controlled studies. Until then, it seems important to recommend the use of the NPSI or other neuropathic pain classification instruments (and the DN4 questionnaire) for the diagnosis and clinical assessment of neuropathic pain, both in daily practice and in further clinical studies.