Risk factors for incident neuropathic pain in HIV infection: the CHARTER study.

Type: Poster
Title: Risk factors for incident neuropathic pain in HIV infection: the CHARTER study.
Authors: Ellis RJ, Rosario D, Clifford D, McArthur J, Simpson D, Alexander T, Marra C, Morgello S, Gelman BB, Dworkin RH, Vaida F, Grant I
Date: 10-2009
Abstract:Background: Despite dramatic improvements in overall health among HIV infected individuals on antiretroviral therapy, neurologic morbidity, including neuropathic pain, continues to rise. We hypothesized that asymptomatic peripheral nerve injury, indicated by abnormal distal sensation and reflexes, would predict incident neuropathic pain in HIV. Because previous studies have demonstrated that a history of opioid dependence increases pain susceptibility, we also analyzed past DSM-IV-diagnosed opioid dependence as a risk factor for incident neuropathic pain. Methods: In a multicenter, prospective, observational study, we assessed 449 pain-free HIV-infected individuals with serial, targeted neurological examinations and clinical interviews. Results: At baseline, participants were mostly middle-aged (mean 43 years) males (81%) with a median [IQR] CD4 nadir of 181 [50323] cells/uL and current CD4 437 [278636]. 229 (51%) had at least one abnormal exam finding consistent with neuropathy and 82 (18%) had a history of opiate dependence or abuse. During a median duration of follow-up of 12 months [IQR 618] among 449 HIV subjects who were pain-free at baseline, 94 developed neuropathic pain. The hazard for developing incident neuropathic pain was increased (1.97 [95% CI: 1.283.03]) for subjects with one or more abnormal neuropathy exam findings at baseline as compared to those without neuropathy. Subjects with 2 or more abnormal signs were at greatest risk (HR 2.51 [95% CI: 1.504.19]; p0.0006), followed by those with only 1 sign (HR 1.65 [95% CI: 1.012.70]; p0.045). Similarly, the hazard was significantly increased (1.85 [95% CI: 1.172.92]) for past history of opiate dependence or abuse. Other predictors evaluated including current CD4, nadir CD4, age, d-drug exposure and hepatitis C infection were not significant predictors of incident pain (p0.05). After controlling for each other in a multivariate proportional hazards model, history of opiate dependence or abuse and neuropathy (at least one abnormal sign) remained significant predictors of incident pain. Conclusions: Abnormal exam findings and a history of opiate dependence or abuse predict subsequent development of neuropathic pain in HIV. Interventions that reduce the probability of acquiring abnormal neuropathy signs may also prevent the development of neuropathic pain.