HIV Infection Care and Viral Suppression Among People Who Inject Drugs, 28 U.S. Jurisdictions, 2012-2013

INTRODUCTION

The National HIV/AIDS Strategy for the United States (NHAS) defines four primary goals: (1) reducing new human immunodeficiency virus (HIV) infections; (2) increasing access to care and improving health outcomes for people living with HIV; (3) reducing HIV-related disparities and health inequities; and (4) achieving a more coordinated

national response to the HIV epidemic [1]. While people who inject drugs (PWID) make up a relatively small share of the U.S. population, their risk of HIV infection is disproportionately high [2]. In 2010, there were more than 6.6 million people aged 13 years and older who had injected drugs during their lifetime and more than 188,000 who were infected with HIV [3, 4].

While new diagnoses of HIV infection among PWID declined from an estimated 6,004 in 2002 to an estimated 1,795 in 2011 (a 70% decrease) [5] and the number of people living with HIV infection attributed to injection-drug use (IDU) declined from 143,500 to 140,700 from 2008 to 2010 [6], continued vigilance is needed to detect PWID who are infected. In 2013 IDU was the third most commonly reported risk factor for HIV infection in the United States after male-to-male sexual contact and heterosexual contact, and IDU was the only known risk factor for an estimated 6.6% of HIV infection diagnoses (5.1% of males and 12.4% of females) [7]. For both male and female PWID almost half of HIV infections in 2013 were among blacks/African Americans. Among male PWID, Hispanics/Latinos and whites each accounted for just under 25% of HIV diagnoses, while among females whites accounted for 34% and Hispanics/Latinos for 15% [7].

The NHAS recommends engagement in care and integration of services for HIV testing and treatment provided by medical professionals, and mental health and substance abuse agencies and practitioners [7]. Specifically, to address the increased risk of PWID contracting HIV infection the NHAS recommends the development of evidence-based HIV prevention recommendations and voluntary routine testing at substance abuse and mental health clinics. However, recent surveys found that three of four PWID reported not participating in a HIV behavioral prevention program and half reported not having been tested for HIV in the past 12 months [8, 9]. Among PWID attending one of five community-based substance abuse treatment programs that offered free HIV testing, nearly one-third had not been tested in the prior 12 months [10]. Data from the Substance Abuse and Mental Health Services Administration (SAMHSA) indicate that less than 50% of substance abuse treatment programs provide on-site infectious disease screening and that inpatient facilities were more likely than non-inpatient facilities to offer such tests [11]. Notwithstanding these challenges, PWID have the lowest percentage of undiagnosed HIV infection [4].

HIV diagnosis is the entry point to the continuum of HIV care, and the 2013 Presidential Continuum of Care Initiative recommended identification of gaps in the other essential steps of the continuum, including linkage to care, retention in care, and antiretroviral (ARV) treatment to achieve the ultimate goal of viral suppression [12]. One study of outpatients presenting for initial HIV primary care found that the mean duration between HIV infection and presentation for HIV-related medical care is as long as eight years [13]. Torian (2008) found that testing at a community testing site or health department and IDU were risk factors for failure to link to care within 3 months of diagnosis [14]. PWID infected with HIV may also have challenges remaining engaged in care or achieve viral suppression. This analysis assessed linkage to and retention in care and viral suppression among people classified by the National HIV Surveillance System (NHSS) as having the single risk factor of injection-drug use. Analyses included examination of the characteristics of persons diagnosed with HIV linked to care, retained in care, and virally suppressed, linkage to care by type of facility at diagnosis and retention in care and viral suppression by stage of disease at diagnosis. This is the first study we know of to look at these components of the continuum of care for PWID using surveillance data, including place and stage of diagnosis for PWID infected with HIV.

METHODS

All data from the National HIV Surveillance System (NHSS), described elsewhere [15], reported to the CDC through December 2014 were used to identify cases of HIV infection meeting the CDC case definition [16] among PWID aged 13 years and older who had received a diagnosis of HIV infection before December 31, 2013 and whose residence at diagnosis was one of 28 jurisdictions. Data were included from jurisdictions that met three criteria:

1. the jurisdiction’s laws/regulations required the reporting of all CD4 and viral load results to the state/city health department;
2. laboratories that perform HIV-related testing for the areas had reported a minimum of 95% of HIV-related test results to the jurisdiction health department; and
3. by December 31, 2014, the jurisdiction had reported (to CDC) at least 95% of all CD4 and viral load test results received from January 2011 through September 2013.

The 28 jurisdictions that met these criteria were Alabama, Alaska, Arkansas, California, District of Columbia, Hawaii, Illinois, Indiana, Iowa, Louisiana, Maine, Maryland, Michigan, Missouri, Nebraska, New Hampshire, New York, North Dakota, Oregon, South Carolina, South Dakota, Tennessee, Texas, Utah, Virginia, Washington, West Virginia, and Wisconsin.

The linkage to care analysis was limited to PWID who were diagnosed with HIV infection during 2013. Linkage to care was defined as ≥1 CD4 or VL test within 3 months of diagnosis. The retention in care and viral load suppression analysis included people who were diagnosed before 2012 and were not known to be deceased on December 31, 2012. Data from 2012 were selected to allow for at least 18 months to report both HIV-infected people and deaths. Retention in care was defined as ≥2 CD4 or VL tests performed at least 3 months apart during 2012. Viral suppression was defined as a viral load test result of <200 copies/mL or, if the quantitative value was missing, a test interpretation value of “undetectable”, at the time of the most recent viral load test during 2012. Laboratory results with no month and year of specimen collection were excluded from the analysis. If there were two test results for the same month with conflicting viral suppression results, the test result that indicated lack of viral suppression was used. In addition, laboratory tests with a blank result and tests with specimen collection dates prior to the date of HIV infection diagnosis were excluded.

Analyses were adjusted for unknown transmission category [7]. Data were stratified by age group (13-24, 25-34, 35-44, 45-54, ≥55), sex, race/ethnicity (black/African American, white, Hispanic/Latino, other), and type of facility at diagnosis (inpatient, outpatient, screening/diagnostic/referral agency, and other). Stage of disease at diagnosis was categorized as early stage infection (defined as the absence of an HIV Stage 3 [AIDS] diagnosis within 3 months of an HIV diagnosis) or late stage infection (defined as the presence of a confirmed HIV Stage 3 [AIDS] diagnosis within 3 month of an HIV diagnosis). All analyses were conducted using SAS 9.3 (SAS Institute, Inc., Cary, NC).

RESULTS

Of the 1,409 PWID with HIV infection diagnosed during 2013 in the 28 jurisdictions, 1,106 (79.2%) were linked to care ≤3 months after HIV diagnosis (Table 1). The estimated percentage of males and females linked to care were similar (78.4% and 80.4%, respectively). African Americans/blacks (hereafter referred to as blacks) (77.5%) were linked to care less often than whites (81.6%) and Hispanic/Latinos (81.4%) as were those in younger age groups (e.g., linkage to care 69.0% among those aged 13-24 years vs. 81.8% among those aged 45-54years). The percentage linked to care was higher among those diagnosed in late-stage infection (98.1%) compared with those not diagnosed in late-stage infection (71.6%).

Linkage to care varied depending on the type of care at time of diagnosis (inpatient, 86.3%; outpatient, 80.4%; and screening, diagnostic or referral agency (SDR), 60.0%) (Table 2). This pattern was observed regardless of sex, race/ethnicity, age at diagnosis, or stage at diagnosis with the greatest absolute difference between inpatient and SDR agencies among those aged 13-24 years (absolute difference 41.9 percentage points), blacks (31.1 percentage points), and females (27.1 percentage points). Males and females diagnosed at inpatient (males=84.5%, females=89.1%), outpatient (males=79.0%, females=81.9%) and SDR (males=58.2%, females=62.0%) facilities were linked to care with similar frequency. Regardless of place of diagnosis, PWID with late stage disease were more likely to be linked to care within three months after care.

Of the 80,958 PWID with HIV infection diagnosed before 2012 and alive on December 31, 2012, 49.7% were retained in care and 42.8% achieved viral suppression (Table 3). Females were both retained in care (53.8%) and achieved viral suppression (45.2%) more often than males (47.1% and 41.3%, respectively). Whites were slightly less likely to be retained in care (47.0%) when compared to other race/ethnicity groups but more likely to achieve viral suppression (45.5%) (Table 3). By age group, both retention in care and viral suppression increased with age (retention in care: 13-24 years, 42.7% and 55 years and older, 49.8%; and viral suppression: 13-24 years, 30.6% and 55 years and older, 45.2%). Retention in care among PWID with infection diagnosed in late stage (47.1%) was lower than among those not with late stage disease (50.6%); viral suppression was similar among PWID with infection diagnosed late compared with those without late stage disease (42.4% and 43.0% respectively).

The higher percentage of retention in care among PWID with infection diagnosed during early stage when compared to those with late stage disease (Table 4) was also generally true by sex and age. By race/ethnicity, however, differences by disease severity at diagnosis were small except for Hispanics/Latinos. Hispanic/Latino PWID with HIV diagnosed late were less likely to be retained in care or have a suppressed viral load. By age, PWID aged <45 years and with HIV diagnosed late more commonly had a suppressed viral load compared with those without late stage disease; however, differences were small for older persons.

DISCUSSION/IMPLICATIONS

This study explores care and treatment among people with HIV infection, reported to the NHSS by December 31, 2014, whose only risk factor was injection drug use, by type of facility and stage of infection at diagnosis. While three of four PWID were linked to HIV care, less than half were retained in care or achieved viral suppression; slightly fewer than care and viral suppression among MSM [4]. Substance use has been linked with HIV infection since the beginning of the epidemic. In people already infected with HIV, substance abuse can impact overall health and accelerate disease progression and mortality [17]. Some studies have found that due to psycho-social instability and co-morbid addictions such as alcohol abuse PWID may be less willing to start or adhere to ARV medications than persons who do not actively inject drugs [17].While measuring adherence can be challenging [18], another study found that PWID were over three times as likely (OR 3.49; 95% CI, 1.45-8.40) to use ARV when enrolled in drug or alcohol treatment programs [19]. Comprehensive prevention strategies that address the complex or syndemic interaction of health, social, and environmental needs of HIV-infected PWID are needed [20-23] and should include HIV testing and counseling and treatment for substance abuse [24].

Similar to other studies, our analysis showed considerable variation in care use between demographic groups. Male PWID were as likely to link to care as female PWID but were less likely to receive regular care and achieve viral suppression. Whites were linked to care more often than blacks and Hispanic/Latinos; however, whites were least likely to be retained in care, although viral suppression was similar for all racial and ethnic groups (range 41.3%-43.7%) with the exception of the race/ethnicity of “other”. Finally, younger PWID were generally less likely to be linked to and retained in care and achieve viral suppression than older PWID [4, 25]. Implementing effective interventions among minorities, males, and youth could improve outcomes for HIV-infected PWID along the continuum of care [24].

In 2010 the National HIV/AIDS Strategy established a target that by 2015 the proportion of persons with HIV linked to care within 3 months of HIV diagnosis increase to 85% [1]. Our results indicate that in 2013, linkage to care was still well below this 2015 target for PWID. In comparing our findings to the continuum of care for men who have sex with men (MSM) [25], we noted that linkage to care among PWID (78.6%) was similar to that for MSM (77.5%). Retention in care estimate (MSM: 50.9%, PWID: 49.4%) and viral suppression were also similar for PWID (42.6%) and MSM (42.0%). In 2015 the updated National HIV/AIDS Strategy for the United States renewed that standard through 2020 but reduced the timeframe for linkage to care from three months to one month [26]. Efforts and resources are still needed to monitor and improve outcomes across the HIV continuum of care for these high-priority populations.

Continued focus on linkage to care is needed for those diagnosed in a screening, diagnostic, or referral agency, especially when compared to inpatient and outpatient settings, for every sex, race/ethnicity, age, and stage of diagnosis category assessed. Public clinics that provide these services play an important role in reaching out to people who do not seek care at traditional health care facilities. In addition to having routine HIV testing available, clinics must consider approaches to proactive linkage to care [14]. Ideally, clinic staff will assist people with HIV with setting up their first appointment and provide or refer PWID to substance abuse treatment programs. Likewise, substance abuse treatment programs could assist by offering on-site infectious disease screening and services for linking people with HIV to care [11]. Access to HIV counseling, testing, and treatment continues to vary widely across drug treatment programs [27], creating a missed public health opportunity to get HIV infections among PWID diagnosed and those living with HIV into care.

More than one in four PWID with HIV had stage 3 [AIDS] HIV infection at the time of diagnosis. Diagnosing HIV early in the course of infection is critical to allow prompt linkage to care and treatment to reduce morbidity and mortality and the potential for the onward transmission of the virus. In addition, diagnosis in the acute stage would benefit prevention as the high viral load levels found in the acute stage substantially increase the risk of transmission [28]. Recent studies found that more frequent and expanded HIV testing for PWID would reduce the number of new infections and be cost effective [29]; however less than half of PWID receive the recommended annual HIV testing [28]. People diagnosed with stage 3 [AIDS] HIV infection (AIDS) may have symptoms and therefore be more likely to be prescribed ARV medications. However, our results indicate that care and viral suppression was low even among PWID with infection diagnosed late.

This study is subject to at least four limitations. First, analysis of NHSS data is limited to 28 jurisdictions (61.4% of all persons aged ≥13 years living with diagnosed HIV infection at year-end 2012, the most recent data) with complete reporting of all levels of CD4 and VL test results and may not be representative of all people who inject drugs in the United States. Second, documentation of the most recent VL might not be indicative of consistent viral suppression in this population over time. Third, not all people with HIV infection are identified and entered in the NHSS, including those who are unaware of their HIV infection status (i.e., not yet diagnosed). Fourth, retention in care does not always mean that people were initiated on ART and thus the percentage of people reaching viral suppression includes both those initiated on ART and those not initiated on ART.

CONCLUSION

CDC has adopted a high-impact prevention approach to advance the goals of the National HIV/AIDS Strategy by using a combination of scientifically proven, cost-effective, and scalable interventions targeted to PWID and other populations at greatest risk for HIV infection [24]. Substance abuse treatment programs, syringe services programs, and community outreach are examples of the behavioral risk reductions and other public health strategies that are critical to the foundation of reducing HIV transmission between PWID and their sex partners [27].

Increasing the proportion of PWID living with HIV who are receiving care is critical for achieving the goals of the National HIV/AIDS Strategy to reduce new infections, improve health outcomes, and decrease health disparities. Greater access to HIV testing and drug treatment facilities as well as targeted strategies for high-risk groups, such as minorities, males and youths, may be needed to achieve improvements at each step of the HIV care continuum.

DISCLAIMER

The findings and conclusions in this report are those of the authors and do not necessarily represent the views of the Centers for Disease Control and Prevention.

CONFLICT OF INTEREST

The authors confirm that this article content has no conflict of interest.

REFERENCES