Although we did use propensity scoring to control for preexisting differences between marijuana use groups on variables that were thought to differentiate the groups, we did not account for other important variables that likely differ between marijuana users and nonusers that may have been related to tobacco use and thoughts about use.HIV infected individuals experience a wide range of medical and psychiatric co-morbidities such as neuropathy, anxiety and depression, as well as adverse side effects associated with antiretroviral treatment.Users of effective antiretroviral therapy experience a range of symptoms including neuropathic pain, nausea, diarrhea, loss of appetite, disturbed sleep, depression and anxiety, and physical sickness; these factors are cited as a common reason for delaying, missing, and discontinuing doses of ART.Despite the major benefits of ART on HIV-related survival, there is an ongoing need to help alleviate medication side effects in order to ensure the long term adherence to antiretroviral treatments that is necessary for optimal health outcomes. Initial randomized controlled studies of HIV-infected individuals with peripheral neuropathy suggest significant reduction of pain with daily marijuana use compared to placebo.The substance in marijuana thought to produce these beneficial effects is delta-9-THC. Several pharmaceutical oral formulations of delta-9-THC are currently FDA approved for treatment of loss of appetite in AIDS as well as chemotherapy-induced nausea and vomiting,ebb and flow bench including Marinol and Dronabinol.
Although Marinol and Dronabinol have been approved for use in AIDS since 1992, frequency of medical marijuana use among HIV-infected individuals has not been well studied. Observation studies of HIV-infected individuals in the U.S. have reported both that current marijuana use is relatively common and that its use may reduce HIV-related symptoms.Prevalence of marijuana use in the general U.S. population, by contrast, is between 3–7%. In a Canadian study, where cannabis has been legal for medicinal use in HIV since 2001, 61% of HIV-infected individuals classified themselves as current medical cannabis users .The demand for medical marijuana appears to be significant, but given that medicinal use is illegal in the majority of U.S. states, this presents a challenge to U.S. drug policy.A previous study in the Women’s Interagency HIV Study , a multisite longitudinal observational study of HIV infection among U.S. women, reported a high prevalence of lifetime marijuana use.Furthermore, a substantial subgroup currently used marijuana at least weekly, and 13% of the 2,308 WIHS women who were not weekly marijuana users at study baseline initiated weekly use between 1994 and 2000.We now extend this previous study to evaluate longitudinal patterns of marijuana use, as well as predictors and motivators of use over a 16-year period during which effective ART came into common use. Since the use of marijuana among chronically ill persons seems to be frequent and ongoing in the U.S., it is important to understand factors that influence use as well as the outcomes related to marijuana use.Interviewer-administered questionnaires are administered twice annually in WIHS, and data are routinely collected on the use of recreational and therapeutic drugs, alcohol, and cigarettes over the past six months .
Questions assess the prevalence and frequency of current marijuana use. Recent marijuana use was assessed by asking participants: “Since your last visit have you used marijuana or hash?” Frequency of use was assessed by asking, “On average, how often did you use marijuana or hash since your last visit?” Validity of self-reported drug use has been shown in multiple studies,although some studies suggest higher reporting of drug use using computer assisted self interview.Between 2004–2008 additional questions on reasons for marijuana use were added to the WIHS interview. Four specific reasons for marijuana use were queried at each visit 2004– 08: to relax, for social situations, to reduce HIV symptoms, and to increase appetite . Respondents reporting marijuana use for other reasons were also asked to describe those reasons with open text responses that were then grouped into meaningful categories. The range of reasons for use was similar at each visit and therefore only the cumulative prevalence of each reason are reported. Marijuana users on ART were also asked whether their marijuana affected how they took their ART medication . In 2009 a question on medicinal marijuana use was added for all women reporting recent marijuana use; this question asked women whether their use of marijuana was “medical, meaning prescribed by a doctor, or recreational, or both.” Each study visit also included collection of demographic, psychosocial, and biological variables as well as a physical examination and labs which include CD4 T-cell count and HIV viral load. The definition of ART was guided by the DHHS/Kaiser Panel 23 and is defined as: the reported use of three or more antiretroviral medications, one of which has to be a protease inhibitor , a non-nucleoside reverse transcriptase inhibitor , an integrase inhibitor, or an entry inhibitor, with one of the nucleoside reverse transcriptase inhibitors abacavir or tenofovir.
Covariates of interest included the following HIV-related variables: CD4 cell count tested at every visit , antiretroviral therapy use in the past six months ; and, among those on ART, adherence to the regimen defined as a self-report of taking antiretroviral drugs as prescribed ≥95% of the time. In addition, we evaluated co-morbidities including self-reported peripheral neuropathy defined as “since your last visit have you experienced numbness, tingling or burning sensations in your arms, legs, hands or feet that lasted for more than two weeks”; self-reported asthma; symptoms of depression assessed via Center for Epidemiologic Studies Depression Scale where a CESD≥16 is defined as a high level of symptoms; diabetes defined by self-report, taking diabetes medication or having serum glucose >125; and self-reported quality of life rated using a shortened Medical Outcome Study-HIV Health Survey with scores ranging from 0 to 10, where 6 or higher was defined as good perceived health. In addition we asked about any use in the past six months of: tobacco, cocaine, and injection drug use, as well as the number of sexual partners in the past six months and condom use during the past six months as measures of sexual risk taking; and age. Race and ethnicity were categorized as White non-Hispanic, Black non-Hispanic, other race nonHispanic, and Hispanic any race. As results were similar for Hispanics of any race and White non-Hispanics they were grouped together in the final analyses. IRB approval was obtained at each study site and informed consent obtained from each participant.We describe participant characteristics at study baseline and in 2010. Prevalence of current marijuana use was plotted over calendar time. Univariate and multivariate logistic regression models clustered by person using GEE were used to evaluate risk factors for current marijuana use at semi-annual visits between 1994 and 2010. Three separate models considered i) any current marijuana use , ii) current daily marijuana use current marijuana use among marijuana users as outcomes. Heavy marijuana use was defined as daily marijuana use in the past six months.We were especially interested in the association between ART use/adherence and marijuana use,4x8ft rolling benches as marijuana use has been reported to help alleviate some ART related side effects and might therefore increase adherence. At each visit, covariates of interest at the same visit were compared to marijuana use at that visit. These models included the following time updated variables: age, CD4 cell count, HIV-status, ART use in the past six months, ART adherence, current peripheral neuropathy, asthma, depression symptoms, diabetes, quality of life, current tobacco, cocaine, and injection drug use, recent number of sexual partners and recent condom use. Race/ethnicity, study site and enrollment wave into study were also included in these models.
All variables significant in univariate analysis and variables of a-priori interest were included in the multivariate models and removed in a stepwise fashion. Final multivariate models for each outcome retained all statistically significant variables as well as those variables of interest from previous research as well as variables significant in the other outcome models, for comparison. The association of current marijuana use on increased odds of ART adherence was similarly modeled. All analysis was done using Stata 11. In 2009–10, marijuana users were asked whether their use was recreational or medicinal . The majority of marijuana users reported some medicinal marijuana use, including 26% of users reporting purely medicinal use and another 29% of users reporting both medicinal and recreational usage,Table 2. Medicinal marijuana use was even more common among heavy marijuana users; among daily marijuana users, more than two-thirds reported some medicinal marijuana use, Table 2. While medicinal marijuana use was common among HIV-infected marijuana users, it remained rare in the study population overall, with 7.1% of women at the 2010 study visit reporting current medicinal marijuana use. More general reasons for marijuana use were asked between 2004 and 2008, with participants asked to indicate all reasons that applied to their marijuana use. The most common reasons reported for marijuana use were: relaxation , appetite stimulation , for social situations , and for reduction of HIV symptoms . Less common reasons reported for use included recreational use, physical pain relief, for mental health reasons, and as a sleep aid . Among those using marijuana daily, use for relaxation and social situations were also common,Table 2. However, daily marijuana users were more likely than less frequent marijuana users to report use for appetite stimulation or for reduction of HIV symptoms . Marijuana users consistently reported that their marijuana use did not affect how they took their HIV medications.This cohort study evaluated marijuana use and related reasons for use every six months over 16 years in a large multi-site study of HIV-infected women in the United States. The study demonstrates that marijuana use is common among HIV-infected women in the U.S., including both recreational and medicinal marijuana use. While the prevalence of marijuana use decreased during study follow-up as participants aged, an increasing proportion of HIV infected women using marijuana in the study also began using marijuana daily. These heavy users reported using marijuana primarily for medicinal purposes, suggesting the rationale for marijuana use among HIV-infected women in this HAART era study may have changed from purely recreational to a combination of recreational and medicinal usage. The prevalence of current marijuana use in this multi-center cohort of HIV-infected women in the U.S. was similar to that reported in several other U.S. studies, although it was lower than a Canadian study which reported 43% of HIV-infected participants used marijuana recently.A previous study of marijuana use in this same WIHS cohort had a lower prevalence of current marijuana use than this study because they had excluded women with an history of daily marijuana use before study baseline.The increasing use of medical marijuana among HIV-infected women in this study is consistent with previous studies showing medicinal use in the majority of HIV-infected marijuana users.In the most recent data in this study, some medicinal marijuana use was reported by 55% of current marijuana users, similar to other U.S. studies which reported medical use in 45–67% of HIV-infected marijuana users.Despite high rates of recreational marijuana use, current rates of medically-prescribed marijuana use remained uncommon overall, reported by 7.1% of HIV-infected women in 2010 in the current study; other studies reported a higher prevalence of current medicinal marijuana use among HIV-infected individuals, but this may in part be explained by our definition of medicinal marijuana use as being prescribed by a doctor. Many women who reporting using marijuana that was not medically prescribed, indicated relief of HIV-related symptoms or increasing appetite as a motivator for use . There was substantial variation in marijuana use between the six U.S. study sites. These differences may reflect differing state laws and availability of any marijuana and medically prescribed marijuana. In California, which had the highest prevalence and increase in medicinal marijuana use during the study, medical marijuana became legal in 1996. Medicinal marijuana was not legalized in the other states in this study during the study period, although in D.C. medicinal marijuana did become legal in 2010. A recent study suggested that states with legal medical marijuana use have a higher prevalence of marijuana use, but that the percent of marijuana users with marijuana dependence/abuse was similar in states with and without laws allowing medical marijuana use.