Is age and not antiretroviral therapy the strongest risk factor for chronic pain in HIV-infected population?

Background: Chronic pain in HIV-infected patients on effective antiretroviral therapy (ART) limits patients' normal functioning both somatically and psychologically. The current state of knowledge on the topic is insufficient, with the underlying causes of this pain unexplained. Therefore we analyzed the frequency and factors associated with chronic pain in HIV-infected patients on ART.

Methods: We conducted a prospective, survey study, including consecutive HIV-infected patients under specialist care at the HIV Outpatient Clinic of the Hospital for Infectious Disease in Warsaw between February 2014 and December 2016. During their routine visit all patients who agreed to participate in the study were surveyed using a study questionnaire. For all patients reporting any pain the Brief Pain Inventory (BPI) form and Douleur Neuropathique 4 Questions form (DN4) were completed. Data on history and current ART and laboratory measurements were obtained from electronical database. Chi-squared and Kruskal-Wallis tests were used for group comparison. The potential factors associated with chronic pain were identified via logistic regression models.

Results: In total 196 HIV-infected patients were included in the study, 57 (29,1%) of them reported chronic pain. The reported pain was mostly (75%) limited to a single area of the body. In univariable logistic regression model the odds of chronic pain were significantly higher with increasing age (OR 1.36 [95%CI:1.17-1.58]), time under specialist care (OR 2.25 [95%CI:1.42-35.7]), time on ART (OR2.96 [95%CI:1.60-5.49]), previous ART with zidovudine (OR 2.00[95%CI:1.06-1.55]) and previous treatment with ddI, ddC or d4T (OR4.13 [95%CI:1.92-8.91]). Homosexual route of HIV infection as compared to injecting drug use was decreasing the odds of chronic pain (OR0.33 [95%CI: 014-0.75]). In multivariable analyses, adjusting for all above the only factor associated with chronic pain was age (OR1.28 [95%CI:1.06-1.55]).

Conclusions: The prevalence of chronic pain in the studied population of HIV-infected Polish patients was high. The only risk factor for chronic pain identified was age. With ageing HIV population it is therefore imperative to develop cooperation protocols for specialist HIV treatment clinics, pain treatment clinics, and rehabilitation units.