Association of HIV and viral suppression status with hospital acute kidney injury in the era of antiretroviral therapy.

In the modern era, it is unknown if people that are virally suppressed with HIV (PWH) are at increased risk for acute kidney injury (AKI) compared to people without HIV and no studies have compared the risk of AKI by viral suppression status. Here, we determined the associations of HIV status and AKI among PWH with and without viral suppression compared to people without HIV. An observational cohort study of PWH and people without HIV hospitalized in a large New York City health system between 2010-2019 was conducted. Multivariable Cox proportional hazards models were used to determine associations between HIV status and risk of AKI, severe AKI and development of chronic kidney disease (CKD). Among 173,884 hospitalized patients, 4,718 had HIV; 2,532 (53.7%) were virally suppressed and 2,186 (46.3%) were not suppressed. Compared to people without HIV, PWH with and without viral suppression were at increased risk of AKI (adjusted hazard ratio 1.27, 95% confidence interval 1.15, 1.40 and 1.73, 1.58, 1.90, respectively) and AKI requiring kidney replacement therapy (1.89, 1.27, 2.84 and 1.87, 1.23, 2.84, respectively). Incremental, graded associations were observed between HIV status and Stage 2 or 3 AKI, and among AKI survivors, and incident CKD. The elevated risk of AKI across ages of PWH was similar in magnitude to older people without HIV. Thus, regardless of virologic control, HIV is an independent risk factor for AKI among hospitalized patients. Future studies should determine the mechanisms by which HIV increases susceptibility to AKI and identify strategies to prevent AKI in PWH.

ASSOCIATION OF SOCIAL NEEDS WITH UNCONTROLLED VIREMIA IN PEOPLE WITH HIV.

Using a tool integrated into the electronic health record, we determined prevalence of 10 social needs among 377 people with HIV (PWH) and 27,833 patients without HIV receiving care in the Montefiore Health System. PWH (median age 53) were 55% women, 41% Black, 44% Hispanic. 33% of PWH reported at least one social need vs. 18% among patients without HIV, with healthcare transportation and housing needs significantly higher among PWH in adjusted analyses. PWH reporting transportation needs were 27% less likely to be virologically suppressed (< 200 copies/mL, adjusted prevalence ratio 0.73, 95% CI 0.55-0.96) compared with PWH without transportation needs.

RESUMEN: Por medio del uso de encuestas integradas en el registro electrónico de salud, determinamos la prevalencia de 10 necesidades sociales entre 377 personas con VIH (PCV) y 27 833 pacientes sin VIH que reciben atención en el Montefiore Health System. PCV (edad mediana de 53 años) fueron 55% mujeres, 41% negras, 44% hispanas. 33% de PCV reportó al menos una necesidad social vs. 18% de los pacientes sin VIH, siendo las necesidades de transporte a cuidados de salud y de vivienda significativamente mayores en PCV en análisis multivariable ajustado. PCV con necesidades de transportación fueron 27% menos probables de tener supresión viral (< 200 copias/ml, razón de prevalencias ajustada 0.73, IC 95% 0.55­0.96) comparada con PCV sin necesidades de transportación.

An expanded HIV screening strategy in the Emergency Department fails to identify most patients with undiagnosed infection: insights from a blinded serosurvey.

Screening for HIV in Emergency Departments (EDs) is recommended to address the problem of undiagnosed HIV. Serosurveys are an important method for estimating the prevalence of undiagnosed HIV and can provide insight into the effectiveness of an HIV screening strategy. We performed a blinded serosurvey in an ED offering non-targeted HIV screening to determine the proportion of patients with undiagnosed HIV who were diagnosed during their visit. The study was conducted in a high-volume, urban ED and included patients who had blood drawn for clinical purposes and had sufficient remnant specimen to undergo deidentified HIV testing. Among 4752 patients not previously diagnosed with HIV, 1403 (29.5%) were offered HIV screening and 543 (38.7% of those offered) consented. Overall, undiagnosed HIV was present in 12 patients (0.25%): six among those offered screening (0.4%), and six among those not offered screening (0.2%). Among those with undiagnosed HIV, two (16.7%) consented to screening and were diagnosed during their visit. Despite efforts to increase HIV screening, more than 80% of patients with undiagnosed HIV were not tested during their ED visit. Although half of those with undiagnosed HIV were missed because they were not offered screening, the yield was further diminished because a substantial proportion of patients declined screening. To avoid missed opportunities for diagnosis in the ED, strategies to further improve implementation of HIV screening and optimize rates of consent are needed.

PrEP in the Real World: Predictors of 6-Month Retention in a Diverse Urban Cohort.

The effectiveness of HIV pre-exposure prophylaxis (PrEP) depends on adherence, which requires retention in PrEP care. We sought to examine factors associated with six-month retention in PrEP care among individuals prescribed PrEP between 2011 and 2015 in a large, academic health system in the Bronx, New York. We used multivariable logistic regression to identify factors independently associated with six-month retention. Among 107 patients, retention at 6 months was 42%. In the multivariable analysis, heterosexual individuals were less likely to be retained in PrEP care at 6 months, but individuals who received prescriptions from attending physicians were more likely to be retained in care. Larger prospective studies are needed to better evaluate the individual and health system factors associated with long-term engagement in PrEP care.

Undiagnosed HIV and HCV Infection in a New York City Emergency Department, 2015.

OBJECTIVES: To measure undiagnosed HIV and HCV in a New York City emergency department (ED). METHODS: We conducted a blinded cross-sectional serosurvey with remnant serum from specimens originally drawn for clinical indications in the ED. Serum was deduplicated and matched to (1) the hospital's electronic medical record and (2) the New York City HIV and HCV surveillance registries for evidence of previous diagnosis before being deidentified and tested for HIV and HCV. RESULTS: The overall prevalence of HIV was 5.0% (250/4990; 95% confidence interval [CI] = 4.4%, 5.7%); the prevalence of undiagnosed HIV was 0.2% (12/4990; 95% CI = 0.1%, 0.4%); and the proportion of undiagnosed HIV was 4.8% (12/250; 95% CI = 2.5%, 8.2%). The overall prevalence of HCV (HCV RNA ≥ 15 international units per milliliter) was 3.9% (196/4989; 95% CI = 2.8%, 5.1%); the prevalence of undiagnosed HCV was 0.8% (38/4989; 95% CI = 0.3%, 1.3%); and the proportion of undiagnosed HCV was 19.2% (38/196; 95% CI = 11.4%, 27.0%). CONCLUSIONS: Undiagnosed HCV was more prevalent than undiagnosed HIV in this population, suggesting that aggressive testing initiatives similar to those directed toward HIV should be mounted to improve HCV diagnosis.

Missed Opportunities for HIV Prevention: Individuals Who HIV Seroconverted Despite Accessing Healthcare.

Individuals with a negative HIV test before a positive one (seroconverters) may represent missed opportunities for prevention. To inform HIV prevention strategies, we aimed to characterize patients who seroconverted despite accessing care. We identified patients at a large, urban healthcare system who seroconverted between 2009 and 2014. Demographics, visits, and HIV-related variables were extracted from the medical records. We performed descriptive statistics, assessed for trends, and tested for associations according to sex. 220 seroconverters were identified: 45% were female, 87% were non-Hispanic Black or Hispanic, and median number of negative tests prior to diagnosis was 2 (IQR 1-3). Overall, 49% reported heterosexual contact as their risk factor and the proportion with heterosexual risk increased over time (24% in 2009 vs. 56% in 2014, p = 0.03). Compared to men, women were older at the time of diagnosis (35 vs. 26 years old, p < 0.01), had more visits between their latest negative and positive HIV test (4 vs. 2, p < 0.01), and were more likely to be diagnosed in the context of screening (64% vs. 56%, p = 0.05). We identified a population that became HIV-infected despite multiple healthcare encounters and undergoing HIV testing multiple times. Patients were mostly heterosexual and almost half were female. To avoid missed opportunities for those already accessing care, HIV prevention efforts should include strategies tailored to individuals with less frequently recognized risk profiles.

Retrospective study of the prevalence and progression of monoclonal gammopathy in HIV positive versus HIV negative patients.

The significance of HIV associated paraproteins and their risk of progression to hematological malignancies remains unclear. We compared the development of hematological malignancies among HIV+ (n = 266) and HIV- (n = 537) patients with monoclonal gammopathies. HIV+ and HIV- patients with a positive serum protein electrophoresis test (SPEP) were studied. HIV+ SPEP+ were more likely to have faint and oligoclonal paraproteins (F-SPEP) and less likely to have discrete bands (D-SPEP) compared to HIV- SPEP+. The incidence of hematological malignancies was significantly lower in the HIV+ compared to the HIV- (6.4% vs 15.4%, p < 0.0002). Upon subgroup analysis, the lower incidence of hematological malignancies was noted for HIV+ patients with F-SPEP but not for those with D-SPEP. Copyright © 2015 John Wiley & Sons, Ltd.

Reaching Key Populations: PrEP Uptake in an Urban Health Care System in the Bronx, New York.

Pre-exposure prophylaxis (PrEP) has been established as an effective HIV prevention tool, but real world studies are limited. To inform dissemination efforts, we sought to describe individuals prescribed PrEP in the largest health care system in the Bronx, New York, an urban region with a high burden of HIV. We used a clinical database and chart review to identify individuals prescribed PrEP between 2011 and 2015 (n = 108). A majority were Black and Hispanic, half were men who have sex with men, and nearly a third were cisgender women who have sex with men. Primary care settings were the most common site of PrEP prescription and PrEP prescription rates increased over time. Despite reaching a diverse patient population, PrEP prescribing rates were low, underscoring the urgent need for PrEP scale-up.

Emerging from the database shadows: characterizing undocumented immigrants in a large cohort of HIV-infected persons.

Little is known about how HIV affects undocumented immigrants despite social and structural factors that may place them at risk of poor HIV outcomes. Our understanding of the clinical epidemiology of HIV-infected undocumented immigrants is limited by the challenges of determining undocumented immigration status in large data sets. We developed an algorithm to predict undocumented status using social security number (SSN) and insurance data. We retrospectively applied this algorithm to a cohort of HIV-infected adults receiving care at a large urban healthcare system who attended at least one HIV-related outpatient visit from 1997 to 2013, classifying patients as "screened undocumented" or "documented". We then reviewed the medical records of screened undocumented patients, classifying those whose records contained evidence of undocumented status as "undocumented per medical chart" (charted undocumented). Bivariate measures of association were used to identify demographic and clinical characteristics associated with undocumented immigrant status. Of 7593 patients, 205 (2.7%) were classified as undocumented by the algorithm. Compared to documented patients, undocumented patients were younger at entry to care (mean 38.5 years vs. 40.6 years, p < 0.05), less likely to be female (33.2% vs. 43.1%, p < 0.01), less likely to report injection drug use as their primary HIV risk factor (3.4% vs. 18.0%, p < 0.001), and had lower median CD4 count at entry to care (288 vs. 339 cells/mm3, p < 0.01). After medical record review, we re-classified 104 patients (50.7%) as charted undocumented. Demographic and clinical characteristics of charted undocumented did not differ substantially from screened undocumented. Our algorithm allowed us to identify and clinically characterize undocumented immigrants within an HIV-infected population, though it overestimated the prevalence of patients who were undocumented.

Viral co-infections and paraproteins in HIV: effect on development of hematological malignancies.

The role of viral co-infections and paraproteins in the development of hematological malignancies (HMs) in HIV remains unclear. Using our large database of HIV+ patients, we investigated whether co-infection and paraproteinemia increase the risk of HM. Data on demographics, hepatitis B (HBV) and hepatitis C virus (HCV) co-infections, paraproteinemia, HIV characteristics, and biopsy proven malignant hematological disorders for HIV+ patients were collected over a 10-year period in a large urban hospital setting. We identified 10,293 HIV+ patients who were followed for a median duration of 53 months. Of the 10,293 patients with HIV, 229 (2.2 %) were diagnosed with a HM. Over 85 % of patients in both groups were tested; no significant difference in the prevalence of chronic HBV or HCV was noted between the HM positive (n = 229) and HM negative (n = 9992) patients. The serum protein electrophoresis test was performed for 1371 of the 10,221 patients. HM positive patients, compared to HM negative, were more likely to be tested for paraproteins (OR 3.3, 95 % CI 2.5-4.4) and more likely to have a discrete paraprotein band (OR 3.3, 95 % CI 1.2-8.9). Discrete paraproteins exclusively correlated with the development of plasma cell malignancies. Faint or oligoclonal protein bands were seen in high grade B cell lymphomas but did not show a significant correlation with HM development. Chronic hepatitis B or C infections did not correlate with the development of HM in HIV; however, viral influence on host gene transformation may have been impacted by anti-viral therapy limiting the duration of high viremic states.

Increased HIV testing among hospitalized patients who declined testing in the emergency department.

Health-care systems have serial encounters with many of the same patients across care settings; however, few studies have examined the role of reoffering HIV testing after a patient declines. We assessed whether an intervention to increase HIV testing among hospitalized patients was associated with increased testing among those who declined a test while in the Emergency Department (ED). We studied 8-week periods pre- and post-implementation of an electronic medical record (EMR)-based intervention to increase HIV testing among hospitalized patients. We included all patients 21-64 years old who had no prior HIV test, declined HIV testing in the ED, and were subsequently hospitalized. We used logistic regression to test for an association between time of hospital admission (pre- vs. post-intervention) and whether an HIV test was performed prior to discharge. Pre- and post-implementation, 220 and 218 patients who declined HIV testing in the ED were hospitalized, respectively. There were no significant demographic or clinical differences among patients pre- and post-implementation. Pre- and post-implementation, the median proportion of patients tested weekly was 6.7% (IQR 6.5%, 10.0%) and 41.4% (IQR 33.3%, 41.9%), respectively (aOR 6.2: 95%CI: 3.6, 10.6). HIV testing increased among hospitalized patients who declined a test in the ED after implementation of an EMR-based intervention. Almost half of the patients who declined testing in the ED ultimately underwent testing after it was reoffered during hospitalization, suggesting that the decision to undergo HIV testing is a dynamic process. Leveraging EMR resources may be an effective tool for expanding HIV testing, and testing should be reoffered to patients who previously declined.

Development of an electronic medical record-based algorithm to identify patients with unknown HIV status.

Individuals with unknown HIV status are at risk for undiagnosed HIV, but practical and reliable methods for identifying these individuals have not been described. We developed an algorithm to identify patients with unknown HIV status using data from the electronic medical record (EMR) of a large health care system. We developed EMR-based criteria to classify patients as having known status (HIV-positive or HIV-negative) or unknown status and applied these criteria to all patients seen in the affiliated health care system from 2008 to 2012. Performance characteristics of the algorithm for identifying patients with unknown HIV status were calculated by comparing a random sample of the algorithm's results to a reference standard medical record review. The algorithm classifies all patients as having either known or unknown HIV status. Its sensitivity and specificity for identifying patients with unknown status are 99.4% (95% CI: 96.5-100%) and 95.2% (95% CI: 83.8-99.4%), respectively, with positive and negative predictive values of 98.7% (95% CI: 95.5-99.8%) and 97.6% (95% CI: 87.1-99.1%), respectively. Using commonly available data from an EMR, our algorithm has high sensitivity and specificity for identifying patients with unknown HIV status. This algorithm may inform expanded HIV testing strategies aiming to test the untested.

National HIV and HCV Screening Rates for Hospitalized People who Use Drugs Are Suboptimal and Heterogeneous Across 11 US Hospitals.

Background: To end the HIV and hepatitis C virus (HCV) epidemics, people who use drugs (PWUD) need more opportunities for testing. While inpatient hospitalizations are an essential opportunity to test people who use drugs (PWUD) for HIV and HCV, there is limited research on rates of inpatient testing for HIV and HCV among PWUD. Methods: Eleven hospital sites were included in the study. Each site created a cohort of inpatient encounters associated with injection drug use. From these cohorts, we collected data on HCV and HIV testing rates and HIV testing consent policies from 65 276 PWUD hospitalizations. Results: Hospitals had average screening rates of 40% for HIV and 32% for HCV, with widespread heterogeneity in screening rates across facilities. State consent laws and opt-out testing policies were not associated with statistically significant differences in HIV screening rates. On average, hospitals that reflexed HCV viral load testing on HCV antibody testing did not have statistically significant differences in HCV viral load testing rates. We found suboptimal testing rates during inpatient encounters for PWUD. As treatment (HIV) and cure (HCV) are necessary to end these epidemics, we need to prioritize understanding and overcoming barriers to testing.

Infection rate following total joint arthroplasty in the HIV population.

The purpose of this study is to review a large series of HIV-infected patients who underwent total joint arthroplasty and identify potential risk-factors for infection. Sixty-nine HIV-infected arthroplasty cases were analyzed with 138 matched controls. Deep infection rate following total hip or knee arthroplasty was 4.4% (3 of 69) among HIV cases compared to 0.72% (1 of 138) among controls, yielding a non-significant 6.22 times increased odds of infection (95% CI 0.64-61.0, P=0.11). Kaplan-Meier survival curves for infection free survival and revision free survival revealed non-significantly decreased survival in HIV cases compared to controls (P=0.06 and P=0.09). Our results suggest that the rate of early joint infection following primary total joint arthroplasty in the HIV-infected population is lower than reported in a number of previously published studies.

Comparing Routine HIV and Hepatitis C Virus Screening to Estimate the Effect of Required Consent on HIV Screening Rates Among Hospitalized Patients.

OBJECTIVES: Routine screening for HIV and hepatitis C virus (HCV) among specified age cohorts is recommended. New York State requires consent before screening for HIV but not HCV. We sought to estimate the effect of the consent requirement on screening rates for HIV. METHODS: We performed a retrospective study of patients hospitalized in 2015-2016 at a tertiary care hospital in the Bronx, New York, during a period when prompts in the electronic health record facilitated screening for HIV and HCV among specified age cohorts. We compared proportions of patients eligible for screening for HIV and/or HCV who underwent screening and used generalized estimating equations and a meta-analytic weighted average to estimate an adjusted risk difference between undergoing HIV screening and undergoing HCV screening. RESULTS: Among 11 938 hospitalized patients eligible for HIV and/or HCV screening, 38.5% underwent screening for HIV and 59.1% underwent screening for HCV. The difference in screening rates persisted after adjusting for patient and admission characteristics (adjusted risk difference = 22.0%; 95% CI, 20.6%-23.4%). CONCLUSIONS: Whereas the requirement for consent was the only difference in the processes of screening for HIV compared with screening for HCV, differences in how the 2 viruses are perceived may also have contributed to the difference in screening rates. Nevertheless, our findings suggest that requiring consent continues to impede progress toward the public health goal of routine HIV screening.

Cryptococcal Antigen Screening and Missed Opportunities for Earlier Diagnosis Among People With HIV and Poor Virologic Control in the Bronx, NY.

BACKGROUND: There is no established cryptococcal antigen (CrAg) screening guideline for people with HIV who are antiretroviral therapy experienced but have poor virologic control. We assessed factors associated with CrAg screening and describe missed opportunities for earlier testing. SETTING: Ambulatory clinics affiliated with Montefiore Medical Center, Bronx, NY. METHODS: This was a retrospective chart review of CrAg screening among asymptomatic people with HIV with absolute CD4 counts 200 cells/mm 3 and HIV viral loads (VLs) > 200 copies/mL receiving HIV care from 2015 to 2020. We used Cox proportional hazards regression to identify predictors of screening, including longitudinal CD4 count and HIV VL as time-varying covariables. Among cases of diagnosed cryptococcosis, we assessed for opportunities for earlier diagnosis. RESULTS: Screening CrAg was performed in 2.9% of 2201 individuals meeting the inclusion criteria. Compared with those not screened, those who were screened had a shorter duration of HIV infection (0.09 vs. 5.1 years; P = 0.001) and lower absolute CD4 counts (12 vs. 24 cells/mm 3 ; P < 0.0001). In a multivariable model stratified by median HIV duration, CD4 < 100 [hazard ratio (HR), 7.07; 95% confidence interval (CI): 2.43 to 20.6], VL > 10,000 (HR, 15.0; 95% CI: 4.16 to 54.0), and a shorter duration of HIV infection (HR, 0.60; 95% CI: 0.42 to 0.86) were associated with screening for those with HIV < 5 years. Among those diagnosed with cryptococcosis (n = 14), 6 individuals had an ambulatory visit in the preceding 6 months but did not undergo screening. CONCLUSION: CrAg screening was infrequently performed in this at-risk population. Those with a longer duration of HIV infection were less likely to undergo CrAg screening, highlighting potential missed opportunities for earlier diagnosis.

Clinical Outcomes and Inflammatory Markers by HIV Serostatus and Viral Suppression in a Large Cohort of Patients Hospitalized With COVID-19.

BACKGROUND: Limited data exist about clinical outcomes and levels of inflammatory and immune markers among people hospitalized with COVID-19 by HIV serostatus and by HIV viral suppression. SETTING: Large tertiary care health system in the Bronx, NY, USA. METHODS: We conducted a retrospective cohort study of 4613 SARS-CoV-2 PCR-positive patients admitted between March 10, 2020, and May 11, 2020. We examined in-hospital intubation, acute kidney injury (AKI), hospitalization length, and in-hospital mortality by HIV serostatus, and by HIV-viral suppression and CD4 counts among people living with HIV (PLWH) using adjusted competing risks regression. We also compared immune and inflammatory marker levels by HIV serostatus and viral suppression. RESULTS: Most patients were either non-Hispanic Black (36%) or Hispanic (37%); 100/4613 (2.2%) were PLWH, among whom 15 had detectable HIV viral load. PLWH compared to patients without HIV had increased intubation rates (adjusted hazard ratio 1.73 [95% CI: 1.12 to 2.67], P = 0.01). Both groups had similar rates of AKI, length of hospitalization, and death. No (0%) virally unsuppressed PLWH were intubated or died, versus 21/81 (26%, P = 0.04) and 22/81 (27%, P = 0.02) of virally suppressed PLWH, respectively. Among PLWH, higher CD4 T-cell counts were associated with increased intubation rates. C-reactive protein, IL-6, neutrophil counts, and ferritin levels were similar between virally suppressed PLWH and patients without HIV, but significantly lower for unsuppressed PLWH (all P < 0.05). CONCLUSIONS: PLWH had increased risk of intubation but similarly frequent rates of AKI and in-hospital death as those without HIV. Findings of no intubations or deaths among PLWH with unsuppressed HIV viral load warrant further investigation.

Brief Report: Acute Kidney Injury in People Living With HIV Hospitalized With Coronavirus Disease 2019: Clinical Characteristics and Outcomes.

BACKGROUND: Data on clinical characteristics and outcomes of people living with HIV (PLWH) hospitalized with coronavirus disease 2019 (COVID-19) who develop acute kidney injury (AKI) are limited. SETTING: Large tertiary health care system in the Bronx, NY. METHODS: We performed a retrospective cohort study of 83 PLWH and 4151 patients without HIV hospitalized with COVID-19 from March 10, 2020, to May 11, 2020. We compared the clinical characteristics and outcomes associated with AKI by HIV serostatus and evaluated HIV-related factors for AKI among PLWH. AKI was defined and staged using Kidney Disease Improving Global Outcomes criteria. RESULTS: The incidence of AKI in hospitalized patients with COVID-19 did not differ significantly by HIV serostatus (54.2% in PLWH vs 49.5% in patients without HIV, P = 0.6). Despite a higher incidence of stage 3 AKI (28.9% vs 17.1% P = 0.05) in PLWH compared with those without HIV, there was no significant difference in the need for renal replacement therapy (22.2% vs 13.4% P = 0.12), renal recovery (76.9% vs 82.5% P = 0.61), or dependence on renal replacement therapy (7.7% vs 3.8% P = 0.27). CD4 T-cell count, HIV-1 RNA viral suppression, and antiretroviral therapy use were not associated with AKI. AKI was associated with increased need for invasive ventilation and in-hospital death, but HIV was not an independent risk factor of in-hospital death after AKI [adjusted hazard ratio 1.01 (95% CI: 0.59 to 1.72), P = 0.98]. CONCLUSIONS: HIV-related factors were not associated with increased risk of AKI in PLWH hospitalized with COVID-19. PLWH hospitalized with COVID-19 had more stage 3 AKI, but outcomes after AKI were similar to those without HIV.

Evaluation of Algorithms Used for PrEP Surveillance Using a Reference Population From New York City, July 2016-June 2018.

OBJECTIVE: Daily tenofovir disoproxil fumarate/emtricitabine (TDF/FTC) use as HIV preexposure prophylaxis (PrEP) is monitored by identifying TDF/FTC prescriptions from pharmacy databases and applying diagnosis codes and antiretroviral data to algorithms that exclude TDF/FTC prescribed for HIV postexposure prophylaxis (PEP), HIV treatment, and hepatitis B virus (HBV) treatment. We evaluated the accuracy of 3 algorithms used by the Centers for Disease Control and Prevention (CDC), Gilead Sciences, and the New York State Department of Health (NYSDOH) using a reference population in Bronx, New York. METHODS: We extracted diagnosis codes and data on all antiretroviral prescriptions other than TDF/FTC from an electronic health record database for persons aged ≥16 prescribed TDF/FTC during July 2016-June 2018 at Montefiore Medical Center. We reviewed medical records to classify the true indication of first TDF/FTC use as PrEP, PEP, HIV treatment, or HBV treatment. We applied each algorithm to the reference population and compared the results with the medical record review. RESULTS: Of 2862 patients included in the analysis, 694 used PrEP, 748 used PEP, 1407 received HIV treatment, and 13 received HBV treatment. The algorithms had high specificity (range: 98.4%-99.0%), but the sensitivity of the CDC algorithm using a PEP definition of TDF/FTC prescriptions ≤30 days was lower (80.3%) than the sensitivity of the algorithms developed by Gilead Sciences (94.7%) or NYSDOH (96.1%). Defining PEP as TDF/FTC prescriptions ≤28 days improved CDC algorithm performance (sensitivity, 95.8%; specificity, 98.8%). CONCLUSIONS: Adopting the definition of PEP as ≤28 days of TDF/FTC in the CDC algorithm should improve the accuracy of national PrEP surveillance.