Michael G. Eberhart

Behind the Cascade: Analyzing Spatial Patterns along the HIV Care Continuum

Background:Successful HIV treatment as prevention requires individuals to be tested, aware of their status, linked to and retained in care, and virally suppressed. Spatial analysis may be useful for monitoring HIV care by identifying geographic areas with poor outcomes. Methods:Retrospective cohort of 1704 people newly diagnosed with HIV identified from Philadelphias Enhanced HIV/AIDS Reporting System in 2008–2009, with follow-up to 2011. Outcomes of interest were not linked to care, not linked to care within 90 days, not retained in care, and not virally suppressed. Spatial patterns were analyzed using K-functions to identify “hot spots” for targeted intervention. Geographic components were included in regression analyses along with demographic factors to determine their impact on each outcome. Results:Overall, 1404 persons (82%) linked to care; 75% (1059/1404) linked within 90 days; 37% (526/1059) were retained in care; and 72% (379/526) achieved viral suppression. Fifty-nine census tracts were in hot spots, with no overlap between outcomes. Persons residing in geographic areas identified by the local K-function analyses were more likely to not link to care [adjusted odds ratio 1.76 (95% confidence interval: 1.30 to 2.40)], not link to care within 90 days (1.49, 1.12–1.99), not be retained in care (1.84, 1.39–2.43), and not be virally suppressed (3.23, 1.87–5.59) than persons not residing in the identified areas. Conclusions:This study is the first to identify spatial patterns as a strong independent predictor of linkage to care, retention in care, and viral suppression. Spatial analyses are a valuable tool for characterizing the HIV epidemic and treatment cascade.

Factors associated with delayed entry into primary HIV medical care after HIV diagnosis.

The aim of the study was to assess the median time between HIV diagnosis and entry into primary HIV medical care in a large urban area and to assess the potential individual, diagnosing facility, and community level factors influencing entry into care. One thousand two hundred and sixty-six individuals diagnosed with HIV in Philadelphia between 1 July 2005 and 30 June 2006 were followed until entry into care through 15 June 2007. Time to entry into care was calculated as a survival time variable and was defined as the time in months between the date of HIV diagnosis and the date more than 3 weeks after diagnosis when a CD4 cell count or percentage and/or HIV viral load were obtained. The median time to entry into care for all individuals was 8 months, with a range of 1–26 months. Factors associated with delayed entry into care included age more than 40 years [hazard ratio (HR) = 0.85; 95% confidence interval (CI) = 0.75–0.97] and diagnosis as an inpatient in the hospital (HR = 0.37; 95% CI = 0.37–0.57). Factors associated with earlier entry into care included Hispanic ethnicity (HR = 1.39; 95% CI = 1.05–1.84), male sex with men as HIV transmission risk factor (HR = 1.27; 95% CI = 1.03–1.56), and residence in a census tract with a high poverty rate (HR = 1.68; 95% CI = 1.22–2.30). Individuals newly diagnosed with HIV in Philadelphia demonstrated marked delays in accessing care highlighting the tremendous need for interventions to improve overall linkage. These interventions should especially be targeted at those aged more than 40 years and those diagnosed in the hospital.

Accuracy of definitions for linkage to care in persons living with HIV

Objective:To compare the accuracy of linkage to care metrics for patients diagnosed with HIV using retention in care and virological suppression as the gold standards of effective linkage. Design:A retrospective cohort study of patients aged 18 years and older with newly diagnosed HIV infection in the City of Philadelphia, 2007–2008. Methods:Times from diagnosis to clinic visits or laboratory testing were used as linkage measures. Outcome variables included being retained in care and achieving virological suppression, 366–730 days after diagnosis. Positive predictive value (PPV), negative predictive value (NPV), and area under the curve (AUC) for each linkage measure and retention, and virological suppression outcomes are described. Results:Of the 1781 patients in the study, 503 (28.2%) were retained in care in the Ryan White system and 418 (23.5%) achieved virological suppression 366–730 days after diagnosis. The linkage measure with the highest PPV for retention was having 2 clinic visits within 365 days of diagnosis, separated by 90 days (74.2%). Having a clinic visit between 21 and 365 days after diagnosis had both the highest NPV for retention (94.5%) and the highest adjusted AUC for retention (0.872). Having 2 tests within 365 days of diagnosis, separated by 90 days, had the highest adjusted AUC for virological suppression (0.780). Conclusions:Linkage measures associated with clinic visits had higher PPV and NPV for retention, whereas linkage measures associated with laboratory testing had higher PPV and NPV for retention. Linkage measures should be chosen based on the outcome of interest.

Individual and community factors associated with geographic clusters of poor HIV care retention and poor viral suppression.

Background:Previous analyses identified specific geographic areas in Philadelphia (hotspots) associated with negative outcomes along the HIV care continuum. We examined individual and community factors associated with residing in these hotspots. Methods:Retrospective cohort of 1404 persons newly diagnosed with HIV in 2008–2009 followed for 24 months after linkage to care. Multivariable regression examined associations between individual (age, sex, race/ethnicity, HIV transmission risk, and insurance status) and community (economic deprivation, distance to care, access to public transit, and access to pharmacy services) factors and the outcomes: residence in a hotspot associated with poor retention-in-care and residence in a hotspot associated with poor viral suppression. Results:In total, 24.4% and 13.7% of persons resided in hotspots associated with poor retention and poor viral suppression, respectively. For persons residing in poor retention hotspots, 28.3% were retained in care compared with 40.4% of those residing outside hotspots (P < 0.05). Similarly, for persons residing in poor viral suppression hotspots, 51.4% achieved viral suppression compared with 75.3% of those outside hotspots (P < 0.0.05). Factors significantly associated with residence in poor retention hotspots included female sex, lower economic deprivation, greater access to public transit, shorter distance to medical care, and longer distance to pharmacies. Factors significantly associated with residence in poor viral suppression hotspots included female sex, higher economic deprivation, and shorter distance to pharmacies. Conclusions:Individual and community-level associations with geographic hotspots may inform both content and delivery strategies for interventions designed to improve retention-in-care and viral suppression.

Adolescent Sexually Transmitted Infections and Risk for Subsequent HIV

OBJECTIVES We estimated the risk of HIV associated with sexually transmitted infection (STI) history during adolescence. METHODS We retrospectively studied a cohort of adolescents (n = 75 273, born in 1985-1993) who participated in the Philadelphia High School STD Screening Program between 2003 and 2010. We matched the cohort to STI and HIV surveillance data sets and death certificates and performed Poisson regression to estimate the association between adolescent STI exposures and subsequent HIV diagnosis. RESULTS Compared with individuals reporting no STIs during adolescence, adolescents with STIs had an increased risk for subsequent HIV infection (incidence rate ratio [IRR] for adolescent girls = 2.6; 95% confidence interval [CI] = 1.5, 4.7; IRR for adolescent boys = 2.3; 95% CI = 1.7, 3.1). Risk increased with number of STIs. The risk of subsequent HIV infection was more than 3 times as high among those with multiple gonococcal infections during adolescence as among those with none. CONCLUSIONS Effective interventions that reduce adolescent STIs are needed to avert future STI and HIV acquisition. Focusing on adolescents with gonococcal infections or multiple STIs might have the greatest impact on future HIV risk.

Location of HIV diagnosis impacts linkage to medical care.

Abstract:We evaluated 1359 adults newly diagnosed with HIV in Philadelphia in 2010–2011 to determine if diagnosis site (medical clinic, inpatient setting, counseling and testing center (CTC), and correctional facility) impacted time to linkage to care (difference between date of diagnosis and first CD4/viral load). A total of 1093 patients (80%) linked to care: 86% diagnosed in medical clinics, 75% in inpatient settings, 62% in CTCs, and 44% in correctional facilities. Adjusting for other factors, diagnosis in inpatient settings, CTCs, and correctional facilities resulted in a 33% (adjusted hazard ratio = 0.77; 95% confidence interval: 0.64 to 0.92), 46% (0.56; 0.42–0.72), and 75% (0.25; 0.18–0.35) decrease in the probability of linkage compared with medical clinics, respectively.

Assessing the Overall Quality of Health Care in Persons Living with HIV in an Urban Environment

Ensuring high quality primary care for people living with HIV (PLWH) is important. We studied factors associated with meeting Health Resources and Services Administration-identified HIV performance measures, among a population-based sample of 376 PLWH in care at 24 Philadelphia clinics. Quality of care was assessed by a patient-level composite of 15 performance measures, focusing on HIV-specific care, vaccinations, and co-morbid condition screening. Adjusted incidence rate ratios (IRR) demonstrated relationships between patient and clinic factors and the performance measures score. The mean number of measures met was 8.52. Older age groups met more measures than 18- to 29-year-olds (age 40-49: adjusted IRR: 1.19, 95% CI: 1.05-1.35; age ≥50: adjusted IRR: 1.19, 95% CI: 1.03-1.35). Higher CD4 counts were associated with meeting more measures compared to CD4 <200 cells/μL (CD4 350-499 cells/μL: adjusted IRR: 1.14, 95% CI: 1.02-1.28; ≥500 cells/μL: adjusted IRR: 1.12, 95% CI: 1.01-1.26). PLWH attending clinics that provide adherence counseling or case management met more measures (adjusted IRR: 1.12, 95% CI: 1.04-1.21; adjusted IRR: 1.08, 95% CI: 1.02-1.14; respectively) than those attending clinics without these services. Limitations include potentially poor performance measure documentation and equal treatment of measures. Future work should focus on improving compliance with performance measures.

Comparison of geographic methods to assess travel patterns of persons diagnosed with HIV in Philadelphia

Travel distance to medical care has been assessed using a variety of geographic methods. Network analyses are less common, but may generate more accurate estimates of travel costs. We compared straight-line distances and driving distance, as well as average drive time and travel time on a public transit network for 1789 persons diagnosed with HIV between 2010 and 2012 to identify differences overall, and by distinct geographic areas of Philadelphia. Paired t-tests were used to assess differences across methods, and analysis of variance was used to assess between-group differences. Driving distances were significantly longer than straight-line distances (p<0.001) and transit times were significantly longer than driving times (p<0.001). Persons living in the northeast section of the city traveled greater distances, and at greater cost of time and effort, than persons in all other areas of the city (p<0.001). Persons living in the northwest section of the city traveled farther and longer than all other areas except the northeast (p<0.0001). Network analyses that include public transit will likely produce a more realistic estimate of the travel costs, and may improve models to predict medical care outcomes.

Viral Loads Among HIV-Infected Persons Diagnosed With Primary and Secondary Syphilis in 4 US Cities: New York City, Philadelphia, PA, Washington, DC, and Phoenix, AZ.

Background:Incident syphilis among HIV-infected persons indicates the ongoing behavioral risk for HIV transmission. Detectable viral loads (VLs) among coinfected cases may amplify this risk. Methods:Primary and secondary cases reported during 2009–2010 from 4 US sites were crossmatched with local HIV surveillance registries to identify syphilis case-persons infected with HIV before or shortly after the syphilis diagnosis. We examined HIV VL and CD4 results collected within 6 months before or after syphilis diagnosis for the coinfected cases identified. Independent correlates of detectable VLs (≥200 copies/mL) were determined. Results:We identified 1675 cases of incident primary or secondary syphilis among persons with HIV. Median age was 37 years; 99.5% were men, 41.1% were African American, 24.5% were Hispanics, and 79.9% of the HIV diagnoses were made at least 1 year before syphilis diagnosis. Among those coinfected, there were no VL results reported for 188 (11.2%); of the 1487 (88.8%) with reported VL results, 809 (54.4%) had a detectable VL (median, 25,101 copies/mL; range, 206–3,590,000 copies/mL). Detectable VLs independently correlated with syphilis diagnosed at younger age, at an sexually transmitted disease clinic, and closer in time to HIV diagnosis. Conclusions:More than half of syphilis case-persons identified with HIV had a detectable VL collected within 6 months of the syphilis diagnosis. This suggests virologic and active behavioral risk for transmitting HIV.

Antiretroviral Prescription and Viral Suppression in a Representative Sample of HIV-Infected Persons in Care in 4 Large Metropolitan Areas of the United States, Medical Monitoring Project, 2011-2013

Background: Comparisons of antiretroviral therapy (ART) prescription and viral suppression among people in HIV care across US metropolitan areas are limited. Medical Monitoring Project, 2011–2013, data were used to describe and compare associations between sociodemographics and ART prescription and viral suppression for persons receiving HIV care. Setting: Chicago, Los Angeles County (LAC), Philadelphia, and San Francisco in the United States. Methods: Bivariate and multivariable methods were used. Results: The proportion of patients prescribed ART (91%–93%) and virally suppressed (79%–88%) was consistent although more persons were virally suppressed in San Francisco compared with the other areas, and a smaller proportion was virally suppressed in Philadelphia compared with Chicago. In the combined cohort, persons aged 30–49 years were less likely than persons 50+ (adjusted prevalence ratio (aPR) –0.97, confidence interval (CI): 0.94 to 0.99); persons reporting non-injection drug use were less likely than non-users (aPR = 0.94, CI: 0.90 to 0.98); and Hispanics were more likely than whites (aPR – 1.04, CI: 1.01 to 1.08) to be prescribed ART. Blacks (aPR = 0.93; CI: 0.87 to 0.99) and homeless persons (aPR = 0.87; CI: 0.80 to 0.95) were less likely to be virally suppressed in the combined cohort. In LAC, persons aged 30–49 years were less likely than those 50+ to be prescribed ART (aPR = 0.94, CI: 0.90 to 0.98). Younger persons (18–29) (aPR = 0.77; CI: 0.60 to 0.99) and persons with less than a high school education (aPR = 0.80; CI: 0.67 to 0.95) in Philadelphia, blacks (aPR = 0.90; CI: 0.83 to 0.99) and men who have sex with women only (aPR = 0.89; CI: 0.80 to 0.99) in Chicago, and homeless individuals in LAC (aPR = 0.80; CI: 0.67 to 0.94) were less likely to be virally suppressed. Conclusion: Data highlight the need to increase ART prescription to achieve viral suppression among younger persons, noninjection drug users, blacks, and homeless persons in US metropolitan areas and underscores the importance of region-specific strategies for affected subgroups.