Chronic pain was reported by a quarter of people living with HIV in an American study published in the Journal of Acquired Immune Deficiency Syndromes. Among people reporting ongoing pain of moderate intensity or worse, individuals who did not receive long-term opioid therapy (LTOT) were at increased risk of missing follow-up appointments and having a detectable viral load. Receiving LTOT was associated with lower rates of virologic failure.
“We found several associations between chronic pain, LTOT, and key HIV continuum measures,” comment the authors. “Specifically, chronic pain in participants not on LTOT was associated with virologic failure and suboptimal retention…we also found a previously undescribed protective association between LTOT and virologic failure.”
They believe their results merit further research to investigate the role of chronic pain management in HIV treatment outcomes. “If future studies confirm that chronic pain directly contributes to virologic failure, this would reinforce the need to develop chronic pain treatment tailored to PLWH [people living with HIV], and, if effective, investigate whether they improve HIV-related outcomes,” write the investigators.
Chronic pain is common among people living with HIV, with research suggesting prevalence between 30% and 85%. There are several reasons why chronic pain is so common in HIV-positive people, including peripheral neuropathy caused by either HIV itself or older anti-HIV drugs (such as didanosine); HIV-related inflammation; and shared risk factors for chronic pain and HIV, including poor mental health and drug use.
Little research has been conducted into the association between chronic pain and HIV treatment-related outcomes.
Investigators from the Centers for AIDS Research Network of Integrated Clinical Systems (CNICS) therefore designed a prospective study involving 2334 HIV-positive adults to see if chronic pain and LTOT were associated with retention in follow-up and virologic suppression.
Participants who received HIV primary care between July 2015 and July 2016 at five centres across the US were eligible for inclusion. During routine follow-up visits, the patients completed the Brief Chronic Pain Questionnaire that asks “How much bodily pain have you had during the last week?” (none to severe) and how long it has lasted. Patients reporting moderate pain or worse for at least three months were considered to have chronic pain and were asked to state the location(s) of their pain.
Study outcomes were retention in care (missed appointment) and virologic suppression (viral load below 1000 copies/ml).
Approximately half the participants were aged 50 years or older, most were male, white, had a high CD4 cell count and were virologically suppressed. Anxiety and depression were both common (23% and 18%, respectively). Recent substance use was reported by 10% of people and 13% reported high-risk alcohol use.
Chronic pain was reported by 25% of the sample. The most common locations for chronic pain were lower back, neuropathy in hands and/or feet, and knee pain. Most of the people with chronic pain reported that this was present in more than one location.
LTOT was prescribed to 15% of people, but use varied considerably between study sites (0% to 25%).
Factors associated with suboptimal retention in care and virologic failure included black race, current alcohol abuse and illicit drug consumption. Conversely, older age was protective against both outcomes. Depression and anxiety were associated with decreased chances of retention in care.
Among people not on LTOT, chronic pain was associated with suboptimal retention (OR = 1.75; 95% CI, 1.36-2.25) and virologic failure (OR = 1.97; 95% CI, 1.39-2.8).
Among people with chronic pain, LTOT had no association with retention in care, but was associated with lower risk of virologic failure (OR = 0.56; 95% CI, 0.33-0.66).
The results were essentially unchanged in a subsequent analysis that took into account the specific pain relief medication and baseline viral load.
The authors emphasise that their results need to be validated in further research that is specifically designed to examine causality and the relationship between chronic pain and engagement with the HIV care continuum.
“Our study underscores the importance of chronic pain as a high-impact comorbidity among PLWH,” conclude the authors. “If studies confirm that chronic pain contributes to virologic failure, future work should include identifying effective chronic pain treatment for PLWH and investigating whether they improve HIV treatment outcomes. In addition, studies that assess potential measured confounders of the association between LTOT and retention are needed.”