Pain in ambulatory HIV-infected patients with and without intravenous drug use

The predictors of pain extent in people living with HIV

OBJECTIVE

To investigate the prevalence of widespread pain among people with HIV (PWH) and describe associations with antiretroviral therapy (ART) and markers of HIV disease stage.

DESIGN

Cross-sectional analysis of cohort study in the United Kingdom and Ireland.

METHODS

Pain information was collected during the baseline visit (conducted from 2013 to 2015) through a self-completed manikin identifying pain at 15 sites from five body regions. Pain was classified as widespread if reported at at least four regions and at least seven sites, or regional otherwise. Chi-squared tests, Kruskal-Wallis tests and ordinal logistic regression were used to consider associations between pain extent and sociodemographic and HIV-related factors.

RESULTS

Among the 1207 participants (614 PWH ≥ 50 years, 330 PWH < 50 years, 263 HIV-negative controls ≥50 years), pain was most commonly reported at the upper (left: 28.9%, right: 28.0%) and lower (left: 25.7%; right: 24.5%) leg, upper (18.6%) and lower (29.7%) back and shoulders (left: 16.0%; right: 16.8%). Widespread pain was more commonly reported in PWH than in HIV-negative controls (PWH ≥ 50 years: 18.7%; PWH < 50 years: 12.7%; HIV-negative ≥50 years: 9.5%) with regional pain reported in 47.6, 44.8 and 49.8%, respectively (global P = 0.001). In multivariable analyses, pain extent was greater in those with lower educational attainment, those exposed to more ART drugs, and those with a higher current CD4 cell count but longer exposure to immunosuppression.

CONCLUSION

Widespread pain is commonly reported in PWH and is associated with longer duration of exposure to HIV, immunosuppression and ART. Our findings call for greater awareness, and interventions to support the management, of pain in PWH.

Prescription of High-Dose Opioids Among People Living with HIV in British Columbia, Canada

People living with HIV (PLHIV) often experience pain for which opioid medications may be prescribed. Thus, these individuals are particularly vulnerable to opioid-related harms, including overdose, misuse, and addiction, particularly when prescribed at high doses. We used a comprehensive linked population-level database of PLHIV in British Columbia (BC) to identify demographic and clinical characteristics associated with being prescribed any high-dose opioid analgesic, defined as > 90 daily morphine milligram equivalents (MME/day). Among PLHIV who were prescribed opioids between 1996 and 2015 (n = 10,780), 28.2% received prescriptions of > 90 MME/day at least once during the study period. Factors positively associated with being prescribed high-dose opioid analgesics included: co-prescription of benzodiazepines (adjusted odds ratio [AOR] = 1.14; 95% confidence interval 1.11-1.17); presence of an AIDS-defining illness (ADI; AOR = 1.78; 95% CI 1.57-2.02); seen by an HIV specialist (AOR = 1.24; 95% CI 1.20-1.29); substance use disorder (AOR = 1.46; 95% CI 1.25-1.71); and more recent calendar year (AOR = 1.05; 95% CI 1.04-1.06). Given the known risks associated with high-dose opioid prescribing, future research efforts should focus on the clinical indication and outcomes associated with these prescribing practices.

Is symptom prevalence and burden associated with HIV treatment status and disease stage among adult HIV outpatients in Kenya? A cross-sectional self-report study

People with HIV experience a high prevalence and burden of physical and psychological symptoms throughout their disease trajectory. These have important public and clinical health implications. We aimed to measure: the seven-day period prevalence of symptoms, the most burdensome symptoms, and determine if self-reported symptom burden is associated with treatment status, clinical stage and physical performance. We conducted a cross-sectional study among adult (aged at least 18 years) patients with HIV, attending HIV outpatient care in Kenya. Data was gathered through self-report using the Memorial Symptom Assessment Scale-Short Form (MSAS-SF), file extraction (sociodemographic data, treatment status, CD4 count, clinical stage) and through observation using the Karnofsky Performance Scale (KPS). Multivariable ordinal logistic regression assessed the association of symptom burden (MSAS-SF) controlling for demographic and clinical variables. Of the 475 participants approached, 400 (84.2%) participated. Ordinal logistic regression showed that being on HIV treatment was associated lower global distress index (in quartiles) (odds ratio .45, 95% CI .23 to .88; p = 0.019). Pain and symptom burden still persist in the era of antiretroviral therapy. Routine clinical practice should incorporate assessment and management of pain and symptoms irrespective of disease stage and treatment status in order to achieve the proposed fourth ^"90" in the UNAIDS 90-90-90 targets (that is good quality of life).

Examining HIV-Related stigma in relation to pain interference and psychological inflexibility among persons living with HIV/AIDS: The role of anxiety sensitivity

Pain is highly prevalent among people living with HIV (PLHIV). Although the association between stigma and pain among stigmatized individuals has been well-established in the non- HIV chronic pain literature, little is known about the association between stigma and pain among PLHIV and the mechanisms that underlie this association. The present study examined the indirect effect of HIV stigma and pain via anxiety sensitivity (fear of anxiety symptoms). The sample included 97 PLHIV (60.2% male, M_age = 48.40, SD = 7.75). Results indicated significant and medium-sized indirect effects of HIV stigma on pain severity, pain interference, and psychological inflexibility in pain via anxiety sensitivity. Alternative models did not yield significant indirect effects. The results suggest anxiety sensitivity may explain the association between stigma and pain among PLHIV. These findings provide novel empirical insight into the nature of stigma-pain relation among PLHIV and could be used to guide pain-based intervention development for this population.

High prevalence of pain among adult HIV-infected patients at University of Gondar Hospital, Northwest Ethiopia

BACKGROUND

HIV/AIDS are pressing global health problems. Pain is a common symptom reported by patients living with HIV/AIDS. The exact cause of pain in HIV patients has not been thoroughly described, but it may, due to a symptom of HIV itself, result from opportunistic infections, as a side effect of antiretroviral drugs, concurrent neoplasia or other causes. In addition, pain perception of HIV-infected patients is highly variable and may vary based on cultural context and patient demographics. In Ethiopia, there is insufficient evidence on the prevalence and factors associated with HIV-related pain.

METHODS

A cross-sectional study was conducted among 422 adult HIV-infected patients at Gondar University Hospital antiretroviral care clinic from March 1 to May 1, 2016. Systematic random sampling was used to select study participants. A pretested interviewer-administered questionnaire and a standardized medical record data abstraction tool were used to collect data. A short form brief pain inventory tool was used to measure the outcome. Bivariate and multivariate logistic regression models were fitted to identify factors associated with pain among adult HIV patients.

RESULTS

The prevalence of pain was found to be 51.2% (95% CI: 46.4%-55.9%). Headache (17.9%), abdominal pain (15.6%), and backache (13.3%) were the most common symptoms of study participants. Being female (adjusted odds ratio [aOR]=1.8, 95% CI: 1.1-2.9); regular alcohol intake (aOR=3.3, 95% CI: 1.5-7.2); baseline World Health Organization clinical disease stage: II (aOR=2.5, 95% CI: 1.2-4.9), III (aOR=2, 95%, CI: 1.1-3.6), and IV (aOR=2.4, 95% CI: 1.1-5.3); and the presence of a chronic comorbid condition (aOR=5.9, 95% CI: 2.1-16.7) were significantly associated with pain.

CONCLUSION

Adult HIV patients in this sample reported a high level of chronic pain. Healthcare providers should better implement a routine pain assessment among HIV-positive patients to alleviate their suffering.

Physical pain is common and associated with nonmedical prescription opioid use among people who inject drugs

Background

People who inject drugs (PWID) often have poor health and lack access to health care. The aim of this study was to examine whether PWID engage in self-treatment through nonmedical prescription opioid use (NMPOU). We describe the prevalence and features of self-reported physical pain and its association with NMPOU.

Methods

PWID (N = 702) in San Francisco, California (age 18+) were recruited to complete interviewer administered surveys between 2011 and 2013. Multivariate logistic regression analysis was conducted to examine the associations among self-reported pain dimensions (past 24-h average pain, pain interference with functional domains) and NMPOU, controlling for age, sex, psychiatric illness, opioid substitution treatment, homelessness, street heroin use and unmet healthcare needs.

Results

Almost half of the sample reported pain, based on self-reported measures in the 24 h before their interview. The most common pain locations were to their back and lower extremities. Past 24-h NMPOU was common (14.7%) and associated with past 24 h average pain intensity on a 10 point self-rating scale (adjusted odds ratio [AOR] = 2.15, 95% confidence interval [CI] 1.21–3.80), and past 24 h pain interference with general activity (AOR 1.82 [95% CI 1.04–3.21]), walking ability (AOR 2.52 [95% CI 1.37–4.63]), physical ability (AOR 2.01 [95% CI 1.16–3.45]), sleep (AOR 1.98 [95% CI 1.13–3.48]) and enjoyment of life (AOR 1.79 [95% CI 1.02–3.15]).

Conclusion

Both pain and NMPOU are common among PWID, and highly correlated in this study. These findings suggest that greater efforts are needed to direct preventive health and services toward this population.

Pain and Mortality Risk in a Cohort of HIV-Infected Persons with Alcohol Use Disorders

Pain has been associated with increased risk for mortality in some studies. We analyzed data from a cohort study [HIV-longitudinal interrelationships of viruses and ethanol (HIV-LIVE)] of HIV-infected persons with alcohol use disorders enrolled 2001-2003 to explore whether reporting moderate or greater pain interference was associated with mortality. The main independent variable was pain that at least moderately interfered with work based on a single question from the SF-12. Primary analyses dichotomized at "moderately" or above. Cox proportional hazards models assessed the association between pain interference and death adjusting for demographics, substance use, CD4 count, HIV viral load and co-morbidities. Although significant in unadjusted models (HR = 1.58 (95 % CI 1.03-2.41; p value = 0.04)), after adjusting for confounders, ≥moderate pain interference was not associated with an increased risk of death [aHR = 1.30 (95 % CI 0.81-2.11, p value = 0.28)]. Among HIV-infected persons with alcohol use disorders, we did not detect a statistically significant independent association between pain interference and risk of death after adjustment for potential confounders.

Is HIV Painful? An Epidemiologic Study of the Prevalence and Risk Factors for Pain in HIV-infected Patients

OBJECTIVES

To evaluate the prevalence, impact, and risk factors for pain among a cohort of human immunodeficiency virus (HIV)-infected adults treated with combination antiretroviral therapy if indicated according to current guidelines.

METHODS

This was a cross-sectional epidemiological observational study. All patients attending 1 HIV-outpatient center in the United Kingdom in a 10-month period were eligible. Patients completed a validated questionnaire enquiring about demographics, HIV factors, and symptoms of pain.

RESULTS

Of 1050 eligible participants, 859 (82%) completed a questionnaire. The 1-month period prevalence of pain lasting >1 day was 62.8% among whom 63% reported current pain. The prevalence of pain at most anatomic sites was broadly similar to that observed in population studies using the same questionnaires except that we found considerably higher rates of foot/ankle pain. The median duration of pain was 3 years (range, 0 to 51 y) and the median pain score was 5.0 on an 11-point visual analogue score. Over 40% of people in pain had consulted their primary care physician and >20% were taking analgesics daily. Independent risk factors for current pain were older age (P=0.001), time since diagnosis of HIV infection (P=0.001), and receipt of a protease inhibitor-based regimen (P=0.04).

DISCUSSION

Pain, and notably foot/ankle pain, is common among adults living with prevalent HIV and is associated with substantial morbidity and health care utilization.

Denial of prescription analgesia among people who inject drugs in a Canadian setting

INTRODUCTION AND AIMS

Despite the high prevalence of pain among people who inject drugs (PWIDs), clinicians may be reluctant to prescribe opioid-based analgesia to those with a history of drug use or addiction. We sought to examine the prevalence and correlates of PWIDs reporting being denied of prescription analgesia (PA). We also explored reported reasons for and actions taken after being denied PA.

DESIGN AND METHODS

Using data from two prospective cohort studies of PWIDs, multivariate logistic regression was used to identify the prevalence and correlates of reporting being denied PA. Descriptive statistics were used to characterise reasons for denials and subsequent actions.

RESULTS

Approximately two-thirds (66.5%) of our sample of 462 active PWIDs reported having ever been denied PA. We found that reporting being denied PA was significantly and positively associated with having ever been enrolled in methadone maintenance treatment (adjusted odds ratio 1.76, 95% confidence interval 1.11-2.80) and daily cocaine injection (adjusted odds ratio 2.38, 95% confidence interval 1.00-5.66). The most commonly reported reason for being denied PA was being accused of drug seeking (44.0%). Commonly reported actions taken after being denied PA included buying the requested medication off the street (40.1%) or obtaining heroin to treat pain (32.9%).

DISCUSSION AND CONCLUSIONS

These findings highlight the challenges of addressing perceived pain and the need for strategies to prevent high-risk methods of self-managing pain, such as obtaining diverted medications or illicit substances for pain. Such strategies may include integrated pain management guidelines within methadone maintenance treatment and other substance use treatment programs.

Pain is associated with risky drinking over time among HIV-infected persons in St. Petersburg, Russia

BACKGROUND

Pain is highly prevalent among persons with HIV. Alcohol may be used to "self-medicate" pain. This study examined the association between pain and risky alcohol use over time in a cohort of HIV-infected Russian drinkers.

METHODS

This secondary analysis utilized longitudinal data from a randomized trial of a behavioral intervention. Subjects included HIV-infected adults who reported past 6-month risky drinking and unprotected sex and were recruited from HIV and addiction treatment sites in St. Petersburg, Russia. The main independent variable was pain that at least moderately interfered with daily living. The primary outcome was past month risky drinking amounts based on NIAAA guidelines. General estimating equations (GEE) logistic regression models were used to calculate odds ratios and 95% confidence intervals for the association between pain and risky drinking over time (i.e., baseline, 6 and 12 months), adjusting for potential confounders.

RESULTS

Baseline characteristics of participants (n=699) were mean age of 30 (SD ±5) years, 41% female, and 22% <9th grade education. Nearly one quarter (24%) had a CD4 cell count <200 cells/μl, and only 17% were on antiretroviral therapy. Nearly half (46%) reported at least moderate pain interference in the past month and 81% were drinking risky amounts. In adjusted longitudinal GEE models, pain was significantly associated with greater odds of reporting past month risky drinking (AOR = 1.34, 95% CI: 1.05-1.71, p value=0.02).

CONCLUSIONS

Among a cohort of HIV-infected Russian drinkers, pain that at least moderately interfered with daily living was associated with higher odds of reporting risky drinking amounts over time.

Pain in people living with HIV/AIDS: a systematic review

INTRODUCTION

Pain is one of the most commonly reported symptoms in people living with HIV/AIDS (PLWHA). However, wide ranges of pain prevalence have been reported, making it difficult to determine the relative impact of pain in PLWHA. A systematic review of the literature was conducted to establish the prevalence and characteristics of pain and to explore pain management in PLWHA.

METHODS

Studies that included cross-sectional data were included in the search, which was conducted in April 2012. Databases searched using a time limit of March 1982 to March 2012 included PubMed, Scopus, Africa-wide: NIPAD, CINAHL, PsychARTICLES, PSYCINFO, PSYCHIATRYONLINE, ScienceDirect and Web of Science. Search terms selected were "pain" and "HIV" or "acquired immune deficiency syndrome." Two reviewers independently screened all citation abstracts for inclusion. Methodological quality was evaluated using a standardized 11-item critical appraisal tool.

RESULTS

After full text review, 61 studies fulfilled the inclusion criteria. Prevalence of pain ranged from a point prevalence of 54% (95%CI 51.14-56.09) to 83% (95%CI 76-88) using a three-month recall period. The reported pain was of moderate-to-severe intensity, and pain was reported in one to two and a half different anatomical sites. Moderate levels of pain interference with function were reported. All nine studies reporting on the adequacy of pain management recorded marked under-treatment of pain.

DISCUSSION

The studies reviewed reported that pain commonly presents at multiple pain sites with a range of severity suggesting that there are several differing pathological processes contributing to pain at one time. The interplay of variables associated with pain suggests that the biopsychosocial model of pain is an appropriate paradigm from which to view pain in PLWHA and from which to approach the problem, explore causes and establish effective treatment.

CONCLUSIONS

The results highlight that pain is common in PLWHA at all stages of the disease. The prevalence rates for pain in PLWHA do not appear to have diminished over the 30 years spanning the studies reviewed. The body of work available in the literature thus far, while emphasizing the problem of pain, has not had an impact on its management.

Pain is associated with heroin use over time in HIV-infected Russian drinkers

AIMS

To evaluate whether pain was associated with increased risk of using heroin, stimulants or cannabis among HIV-infected drinkers in Russia.

DESIGN

Secondary analysis of longitudinal data from the HERMITAGE study (HIV's Evolution in Russia-Mitigating Infection Transmission and Alcoholism in a Growing Epidemic), a behavioral randomized controlled trial, with data collected at baseline, 6-month and 12-month visits.

SETTING

Recruitment occurred at HIV and addiction treatment sites in St Petersburg, Russian Federation.

PARTICIPANTS

Six hundred and ninety-nine HIV-infected adult drinkers.

MEASUREMENTS

The primary outcome was past month illicit drug use; secondary outcomes examined each drug (heroin, stimulants and cannabis) separately. The main predictor was pain that interfered at least moderately with daily living. General estimating equations (GEE) logistic regression models were used to evaluate the association between pain and subsequent illicit drug use, adjusting for potential confounders.

FINDINGS

Participants reporting pain appeared to have higher odds of using illicit drugs, although the results did not reach statistical significance [adjusted odds ratio (OR) = 1.32; 95% confidence interval (CI) = 0.99, 1.76, P = 0.06]. There was a significant association between pain and heroin use (OR = 1.54; 95% CI = 1.11-2.15, P = 0.01) but not use of other drugs (OR = 0.75; 95% CI =0.40-1.40, P = 0.35 for stimulants and OR = 0.70; 95% CI = 0.45-1.07, P = 0.09 for cannabis).

CONCLUSIONS

HIV-infected Russian drinkers who report pain are more likely to use heroin over time than HIV-infected Russian drinkers who do not report pain. Pain may be an unrecognized risk factor for persistent heroin use with implications for HIV transmission in Russia.

Pain treatment in patients infected with human immunodeficiency virus in later stages: pharmacological aspects

Pain is a common and debilitating symptom of human immunodeficiency virus (HIV) disease, although it is often underestimated and undertreated, especially in HIV-infected intravenous drug users. It is more likely to occur in the later stages of the HIV disease, where it assumes particular significance, especially in terminally ill patients. However, its successful management is possible, though the goal of effective therapy is hampered by the side effects of highly active antiretroviral therapy and drug-drug interactions. In order to appraise these issues, a search in MEDLINE database was conducted. Book reviews and a search on relevant Web sites were also included. Treatment of HIV is itself very complex and becomes even more difficult when palliative therapy is added. Protease inhibitors, mainly ritonavir, and nonnucleoside reverse transcriptase inhibitors have higher interaction potential, due to their inducer or inhibitory actions on cytochrome P450, posing a risk when coadministered with palliative treatments; so, better outcomes can be achieved with knowledge of pharmacological aspects.

Hepatitis C virus infection is associated with painful symptoms in HIV-infected adults

The study aim was to assess whether hepatitis C virus (HCV) was associated with painful symptoms among patients with HIV. Using data from a prospective cohort of HIV-infected adults with alcohol problems, we assessed the effects of HCV on pain that interfered with daily living and painful symptoms (muscle/joint pain, headache and peripheral neuropathy). Exploratory analyses assessed whether depressive symptoms and inflammatory cytokines mediated the relationship between HCV and pain. HCV-infected participants (n = 200) had higher odds of pain that interfered with daily living over time (adjusted odds ratio [AOR] 1.43; 95% CI: 1.02-2.01; p = 0.04) compared to those not infected with HCV. HIV/HCV co-infected participants had higher odds of muscle or joint pain (AOR 1.45; 95% CI: 1.06-1.97; p = 0.02) and headache (AOR 1.57; 95% CI: 1.18-2.07; p<0.01). The association between HCV and peripheral neuropathy did not reach statistical significance (AOR 1.33; 95% CI: 0.96-1.85; p = 0.09). Depressive symptoms and inflammatory cytokines did not appear to mediate the relationship between HCV and pain. Adults with HIV who are also co-infected with HCV are more likely to experience pain that interfered with daily living, muscle or joint pain, and headaches compared to those not co-infected. Research is needed to explore the association between HCV infection and pain, and to determine whether HCV treatment is an effective intervention.

The mediating role of pain in substance use and depressive symptoms among Multicenter AIDS Cohort Study (MACS) participants

Pain in human immunodeficiency virus (HIV) frequently co-occurs with substance use and depression. The complex associations among patient characteristics, pain, depression, and drug use in HIV suggests a role for testing models that can account for relationships simultaneously, control for HIV status, and also test for mediation. Using structural equation modeling, the current study examined associations among pain, sociodemographics, illicit drug use, and depressive symptoms in 921 HIV-seropositive and 1019 HIV-seronegative men from the Multicenter AIDS Cohort Study, an ongoing prospective study of the natural history of HIV infection among gay/bisexual men. Longitudinal repeated measures data collected over a 6-year period were analyzed using predictive path models in which sociodemographics, HIV status, and CD4+ cell counts predicted pain, which, in turn, predicted depressive symptoms and illicit drug use. The path models did not differ substantially between HIV-seropositive and -seronegative men. Analyses using the total sample indicated that pain served both as a mediator and as a predictor of more use of cannabis, cocaine, and heroin, as well as more depressive symptoms. HIV-seropositive status predicted more use of inhaled nitrites. In this cohort, having lower CD4+ cell counts (predicted by HIV status), being African American, less educated, and older were all associated with more pain, which, in turn, was associated with more illicit drug use and more depressive symptoms. The results underscore the need for adequate pain management, particularly among vulnerable subgroups of HIV-seropositive and HIV-seronegative men to reduce the risk of drug use and depression.

Chronic pain and hepatitis C virus infection in opioid dependent injection drug users

It is unknown whether infection with hepatitis C is a risk factor for pain among people who have used injection drugs. Multivariate regression was used to determine whether hepatitis C was associated with greater likelihood of reporting significant chronic pain and discomfort intolerance in a cohort of 97 injection drug users dependent on opioids. Study results suggest that participants with hepatitis C may be more likely to experience chronic pain (aOR=1.98; 95% confidence interval=0.76 to 5.12, p=0.16). Furthermore, hepatitis C was found to be associated with a higher discomfort intolerance scale score, reflecting intolerance to physical discomfort (β=2.34; 95% confidence interval=0.06 to 4.62; p=0.04). Hepatitis C may be a cause for chronic pain and discomfort intolerance that is overlooked among injection drug users dependent on opioids.

Sex differences in pain and misuse of prescription analgesics among persons with HIV

OBJECTIVE

Women represent the largest percentage of new HIV infections globally. Yet, no large-scale studies have examined the experience of pain and its treatment in women living with HIV.

DESIGN

This study used structural equation modeling to examine sex differences in pain and the use and misuse of prescription analgesics in a representative sample of HIV+ persons in the United Stated within a prospective, longitudinal design.

OUTCOME MEASURES

Bodily pain subscale of the Short-Form 36 and Modified Short Form of the World Health Organization's Composite International Diagnostic Interview (opioid misuse).

RESULTS

Women reported more pain than men over a roughly 6-month period regardless of mode of HIV transmission or prior drug use history. Men acknowledged more misuse of prescription analgesics over an approximate 1-year period compared with women, after taking into account pain, use of analgesics specifically for pain, and drug use history. Weaker associations between pain and use of analgesics specifically for pain that persisted over time were found among women compared with men. For both men and women, pain was stable over time. Problem drug use history exerted significant direct and indirect effects on pain, opioid misuse, and pain-specific analgesic use across sex.

CONCLUSION

The current findings are consistent with prior evidence indicating female pain predominance as well as the undertreatment of pain among women with HIV. Efforts should be made to improve the assessment and long-term management of pain in HIV+ persons.

Access to pain treatment as a human right

BACKGROUND

Almost five decades ago, governments around the world adopted the 1961 Single Convention on Narcotic Drugs which, in addition to addressing the control of illicit narcotics, obligated countries to work towards universal access to the narcotic drugs necessary to alleviate pain and suffering. Yet, despite the existence of inexpensive and effective pain relief medicines, tens of millions of people around the world continue to suffer from moderate to severe pain each year without treatment.

DISCUSSION

Significant barriers to effective pain treatment include: the failure of many governments to put in place functioning drug supply systems; the failure to enact policies on pain treatment and palliative care; poor training of healthcare workers; the existence of unnecessarily restrictive drug control regulations and practices; fear among healthcare workers of legal sanctions for legitimate medical practice; and the inflated cost of pain treatment. These barriers can be understood not only as a failure to provide essential medicines and relieve suffering but also as human rights abuses.

SUMMARY

According to international human rights law, countries have to provide pain treatment medications as part of their core obligations under the right to health; failure to take reasonable steps to ensure that people who suffer pain have access to adequate pain treatment may result in the violation of the obligation to protect against cruel, inhuman and degrading treatment.

Pain in persons living with HIV and comorbid psychologic and substance use disorders

OBJECTIVES

There is a dearth of information on the experience of pain in persons living with human immunodeficiency virus (HIV) and cooccurring psychologic and substance use problems. This study examined the prevalence and correlates of pain in 162 HIV-positive persons diagnosed with mood and/or anxiety disorders and substance use disorders.

METHODS

Bodily pain scores in the current sample were compared with pain scores in the United States general population and HIV-positive persons who screened negative for psychologic and substance use problems. Bivariate analyses were used to identify significant correlates of pain scores in the current sample, which were then subjected to multiple regression analysis.

RESULTS

Pain scores in the current sample were significantly lower (indicating more pain) than the general population and HIV-positive persons who screened negative for psychologic and substance use problems. Multivariate analysis indicated that the presence of mood disorder, older age, and lower CD4 cell counts (below 200) were associated with increased pain. Presence of mood disorder accounted for the largest amount of unique variance in pain scores.

DISCUSSION

HIV-positive persons with diagnosed mood/anxiety and substance use disorders reported substantially higher levels of pain than the general population and HIV-positive persons without these comorbid conditions. The presence of mood disorder emerged as an important marker for pain in the current sample. Given that individuals living with HIV and comorbid psychologic and substance use disorders are at increased risk for pain, concerted efforts should be directed at identifying and treating pain in this population.

Experience of pain among women with advanced HIV disease

We evaluated pain frequency and severity in 339 women enrolled in the Women's Interagency HIV Study (WIHS). Among these, 63% were 39 years of age or younger, 17% were white, 54% African American, and 29% Hispanic; 32% did not complete high school; 58% had a CD4 less than 200; 65% had clinical AIDS; 60% were on highly active antiretroviral therapy (HAART); and 32% had a viral load of 50,000 or more. Data were collected between 1996 and 1998. Within the past 6 months 190 (56%) women experienced pain 6 or more days and 168 (50%) women indicated pain severity scores of 4 or 5 (5-point scale). Pain frequency and pain severity were not associated with age, education, ethnicity, current therapy, or location of the WIHS site. Pain frequency and severity were related to lower CD4 count, higher depression, with a history and longer duration of smoking and use of marijuana. Severity was associated with a history of crack/cocaine or heroin use or with injection drug use as the transmission category. In the multivariate models, pain severity was related to CD4 count and depression and to current tobacco use but not to crack, cocaine, heroin, or marijuana use. Pain frequency was related to depression and to former tobacco, crack, cocaine, heroin, or marijuana use but not to current use. The long-term effects of tobacco use may be to increase pain experience but women may also smoke tobacco or use other substances to give mild pain relief. Pain is frequent and often severe among women with HIV requiring medical management.

Comparison of dorsal root ganglion gene expression in rat models of traumatic and HIV-associated neuropathic pain

To elucidate the mechanisms underlying peripheral neuropathic pain in the context of HIV infection and antiretroviral therapy, we measured gene expression in dorsal root ganglia (DRG) of rats subjected to systemic treatment with the anti-retroviral agent, ddC (Zalcitabine) and concomitant delivery of HIV-gp120 to the rat sciatic nerve. L4 and L5 DRGs were collected at day 14 (time of peak behavioural change) and changes in gene expression were measured using Affymetrix whole genome rat arrays. Conventional analysis of this data set and Gene Set Enrichment Analysis (GSEA) was performed to discover biological processes altered in this model. Transcripts associated with G protein coupled receptor signalling and cell adhesion were enriched in the treated animals, while ribosomal proteins and proteasome pathways were associated with gene down-regulation. To identify genes that are directly relevant to neuropathic mechanical hypersensitivity, as opposed to epiphenomena associated with other aspects of the response to a sciatic nerve lesion, we compared the gp120 + ddC-evoked gene expression with that observed in a model of traumatic neuropathic pain (L5 spinal nerve transection), where hypersensitivity to a static mechanical stimulus is also observed. We identified 39 genes/expressed sequence tags that are differentially expressed in the same direction in both models. Most of these have not previously been implicated in mechanical hypersensitivity and may represent novel targets for therapeutic intervention. As an external control, the RNA expression of three genes was examined by RT-PCR, while the protein levels of two were studied using western blot analysis.

Characterization of rodent models of HIV-gp120 and anti-retroviral-associated neuropathic pain

A distal symmetrical sensory peripheral neuropathy is frequently observed in people living with Human Immunodeficiency Virus Type 1 (HIV-1). This neuropathy can be associated with viral infection alone, probably involving a role for the envelope glycoprotein gp120; or a drug-induced toxic neuropathy associated with the use of nucleoside analogue reverse transcriptase inhibitors as a component of highly active anti-retroviral therapy. In order to elucidate the mechanisms underlying drug-induced neuropathy in the context of HIV infection, we have characterized pathological events in the peripheral and central nervous system following systemic treatment with the anti-retroviral agent, ddC (Zalcitabine) with or without the concomitant delivery of HIV-gp120 to the rat sciatic nerve (gp120+ddC). Systemic ddC treatment alone is associated with a persistent mechanical hypersensitivity (33% decrease in limb withdrawal threshold) that when combined with perineural HIV-gp120 is exacerbated (48% decrease in threshold) and both treatments result in thigmotactic (anxiety-like) behaviour. Immunohistochemical studies revealed little ddC-associated alteration in DRG phenotype, as compared with known changes following perineural HIV-gp120. However, the chemokine CCL2 is significantly expressed in the DRG of rats treated with perineural HIV-gp120 and/or ddC and there is a reduction in intraepidermal nerve fibre density, comparable to that seen in herpes zoster infection. Moreover, a spinal gliosis is apparent at times of peak behavioural sensitivity that is exacerbated in gp120+ddC as compared to either treatment alone. Treatment with the microglial inhibitor, minocycline, is associated with delayed onset of hypersensitivity to mechanical stimuli in the gp120+ddC model and reversal of some measures of thigmotaxis. Finally, the hypersensitivity to mechanical stimuli was sensitive to systemic treatment with gabapentin, morphine and the cannabinoid WIN 55,212-2, but not with amitriptyline. These data suggests that both neuropathic pain models display many features of HIV- and anti-retroviral-related peripheral neuropathy. They therefore merit further investigation for the elucidation of underlying mechanisms and may prove useful for preclinical assessment of drugs for the treatment of HIV-related peripheral neuropathic pain.

Pain, problem drug use history, and aberrant analgesic use behaviors in persons living with HIV

Little is known about the relationship between pain and aberrant use of prescription analgesics in persons living with HIV. We examined the predictive and concurrent associations among pain, aberrant use of opioids, and problem drug use history in a nationally representative longitudinal sample of 2267 HIV+ persons. Covariance structure analyses tested a conceptual model wherein HIV+ patients with a history of problematic drug use (n=870), compared to those without such history (n=1397), were hypothesized to report more pain and aberrant opioid use, as well as use of opioids specifically for pain at baseline and 6- and 12-month follow-ups, after controlling for key sociodemographic characteristics. In support of the hypothesized model, patients with a history of problematic drug use reported more pain, and were more likely to report aberrant use of prescription analgesics, as well as use of such medications specifically for pain, compared to patients without such history. We also found a trend toward greater stability of aberrant opioid use over time in problem drug users compared with non-problem users suggesting a persistent pattern of inappropriate medication use in the former group. Our findings suggest that even though HIV+ persons with a history of problematic drug use report on-going patterns of using prescription analgesics specifically for pain, these patients continued to experience persistently higher levels of pain, relative to non-problem users. Among non-problem users, pain was not linked to aberrant use of opioids, but was linked to the use of such medications specifically for pain.

Pharmacological, behavioural and mechanistic analysis of HIV-1 gp120 induced painful neuropathy

A painful neuropathy is frequently observed in people living with human immunodeficiency virus type 1 (HIV-1). The HIV coat protein, glycoprotein 120 (gp120), implicated in the pathogenesis of neurological disorders associated with HIV, is capable of initiating neurotoxic cascades via an interaction with the CXCR4 and/or CCR5 chemokine receptors, which may underlie the pathogenesis of HIV-associated peripheral neuropathic pain. In order to elucidate the mechanisms underlying HIV-induced painful peripheral neuropathy, we have characterised pathological events in the peripheral and central nervous system following application of HIV-1 gp120 to the rat sciatic nerve. Perineural HIV-1 gp120 treatment induced a persistent mechanical hypersensitivity (44% decrease from baseline), but no alterations in sensitivity to thermal or cold stimuli, and thigmotactic (anxiety-like) behaviour in the open field. The mechanical hypersensitivity was sensitive to systemic treatment with gabapentin, morphine and the cannabinoid WIN 55,212-2, but not with amitriptyline. Immunohistochemical studies reveal: decreased intraepidermal nerve fibre density, macrophage infiltration into the peripheral nerve at the site of perineural HIV-1 gp120; changes in sensory neuron phenotype including expression of activating transcription factor 3 (ATF3) in 27% of cells, caspase-3 in 25% of cells, neuropeptide Y (NPY) in 12% of cells and galanin in 13% of cells and a spinal gliosis. These novel findings suggest that this model is not only useful for the elucidation of mechanisms underlying HIV-1-related peripheral neuropathy but may prove useful for preclinical assessment of drugs for the treatment of HIV-1 related peripheral neuropathic pain.

Illness burden mediates the relationship between pain and illicit drug use in persons living with HIV

We investigated predictive and concurrent relationships among reported pain, HIV/AIDS illness burden, and substance use history in 2,267 participants in the longitudinal HIV Cost and Services Utilization Study (HCSUS). Substance use history was classified as screening positive for current illicit drug use (N=253), past drug use (N=617), and non-user (N=1,397) at baseline. To control for demographic correlates, age, sex and socioeconomic status (SES) were included as predictors. Covariance structure models indicated greater pain at baseline among participants acknowledging current substance use. Pain at baseline was also directly predicted by greater HIV/AIDS illness burden, lower SES, and older age. At 6 months, pain was directly predicted by prior pain, worse concurrent HIV/AIDS illness burden and female sex. At 12 months, pain was predicted by older age, prior pain, and concurrent HIV/AIDS illness. It was also modestly but significantly predicted by current substance use at baseline. In addition to the direct effects on pain, there were significant indirect effects of demographic and drug use variables on pain mediated through HIV/AIDS illness burden and prior pain. There were significant and positive indirect effects of current and past drug use, greater age, and lower SES on pain at all three time periods. Pain at 6 months and pain at 12 months were also indirectly impacted by previous illness burden. Our results indicate that HIV+persons who screened positive for current use of a range of illicit substances experienced greater HIV/AIDS illness burden which in turn predicted increased pain.

Painful and non-painful neuropathy in HIV-infected patients: an analysis of somatosensory nerve function

Fifteen to 50% of AIDS-patients suffer from distal predominantly sensory neuropathy (DSP), which is commonly associated with painful symptoms. In the present study, we have focused on the function of fine calibre nerve channels, in 36 consecutive HIV-1-infected patients with painful (PPN) (n=20; 54%) and non-painful (PN) (n=16) sensory neuropathy, assessed by clinical, quantitative thermal testing (QTT) (31/36), and peripheral nerve conduction examination (32/36). Control QTT data were obtained from 49 healthy subjects with a corresponding age- and sex distribution. Demographics, antiviral treatment, immunological status, and nerve conduction examination did not differ between patients with and without painful symptoms. Hypoaesthesia to warmth, cold, and heat pain was observed in both neuropathy groups when compared to healthy controls. However, the perception threshold to warmth was more often impaired (p<0.01) and the level of impairment was more pronounced (p<0.001) in patients with painful neuropathy. Furthermore, increased pain sensitivity to cold was found only in patients with painful symptoms (p<0.05). An abnormal outcome of any QTT parameter was found in all patients with pain, but only among 62% of patients without pain, p<0.01, and the cumulative frequency of abnormalities in any of the four thermal percepts (warmth, cold, heat pain, and cold pain) was higher in patients with painful symptoms, p<0.0001. This study demonstrates a more pronounced impairment of C-fibre-mediated innocuous warm perception in patients with painful neuropathy, which in the setting of impaired or absent heat pain perception suggests a more generalised loss of function in somatosensory C-fibre channels.