Abstract
Objectives. We estimated the proportions of persons living with HIV/AIDS (PLWHA) in New York City (NYC) retained in care and virally suppressed.
Methods. We used routinely reported laboratory surveillance data to measure trends in retention in care and viral suppression in PLWHA in NYC from 2006 through 2010. Our denominator excluded persons lacking any HIV-related laboratory tests during the 5 years prior to the year of analysis.
Results. The proportion of patients retained in care (≥ 1 care visit in a calendar year) was stable, at 82.5% in 2006 and 81.8% in 2010. However, the proportion of persons with evidence of viral suppression increased significantly, from 44.3% to 59.1%. Blacks were least likely to have viral suppression (adjusted prevalence ratio [APR] = 0.89; 95% confidence interval [CI] = 0.87, 0.90). A U-shaped relationship between age and viral suppression was observed, with the 20- to 29-year age group least likely to have a suppressed viral load.
Conclusions. Higher and more plausible proportions retained in care and virally suppressed than national estimates may reflect the difference in methodology and our comprehensive HIV-related laboratory reporting system.
Suppression of viremia in HIV-infected persons is associated with improvements in morbidity and mortality and reduced transmission to uninfected partners.1–6 The US Department of Health and Human Services Panel on Antiretroviral Guidelines for Adults and Adolescents recommends that all patients with HIV undergo regular monitoring of disease status and be treated with antiretroviral therapy (ART).7 However, despite the wide availability of HIV care services in the United States, many HIV-infected persons are not engaged in regular care or receiving ART.8–11
The US National HIV/AIDS Strategy (NHAS) has set many goals, among which are an increase in the proportion of newly diagnosed patients linked to clinical care, the proportion of diagnosed patients receiving regular HIV care, and the proportion achieving and maintaining viral suppression.12 HIV surveillance data routinely reported by state and local health departments to the Centers for Disease Control and Prevention (CDC) have been used to evaluate local and national progress toward meeting the goals.13–16
The CDC recently estimated that among persons living with HIV/AIDS (PLWHA), 45% were retained in care, 40% were prescribed ART, and 31% had a suppressed viral load (≤ 200 copies/mL).17 These estimates were surprisingly low considering the natural history of HIV and wide availability of HIV care in the United States.18–23 The CDC estimate of diagnosed patients receiving ART in the United States was even lower than the global average, 40% in the United States versus 47% worldwide (more than 8 million out of 17 million).24
Monitoring local progress toward meeting the NHAS goals requires accurate estimates, backed up by complete, high-quality data and generated by appropriate methods. In this analysis, we used New York City (NYC) HIV diagnosis and laboratory surveillance data to estimate the proportions of HIV patients retained in care and virally suppressed in NYC from 2006 through 2010.
METHODS
The NYC HIV/AIDS Reporting System is a document-based registry that contains data on all persons in NYC diagnosed and reported with AIDS since 1981 and with HIV since 2000. All positive confirmatory tests for HIV antibody (Western blot or immunofluorescence assay, the prevailing standards in 2006–2010), CD4 counts, viral loads, and nucleotide sequences obtained for genotypic analysis are electronically reportable by laboratories.25 The registry is continuously updated with vital events, laboratory reports matched to existing cases, and new diagnoses obtained through laboratory or provider reporting and confirmed by field investigation. As of December 31, 2012, the registry contained a cumulative total of over 228 000 cases and more than 7 million laboratory reports.
Population
The population included in the analysis consisted of persons diagnosed with HIV in NYC or elsewhere and living in the city as of the end of each calendar year between 2006 and 2010. The NYC Department of Health and Mental Hygiene conducts routine registry data matches to ascertain deaths that occur within the United States and dependent areas, but it has limited means to identify persons who have relocated out of NYC after diagnosis or the last time they received HIV care in NYC. Therefore, we used a method previously described by Dombrowski et al. to include only those patients who had at least 1 HIV-related test (Western blot, CD4, viral load, or genotype) in NYC during the 5 years preceding the year of analysis.26 We excluded patients who were in the NYC HIV registry but had no HIV-related tests in NYC in the past 5 years on the premise that previously diagnosed persons for whom no data existed for such a long period of time were not likely to be living in NYC, particularly those diagnosed with AIDS, those meeting the changing federal thresholds for initiation of ART, and others needing care because of advancing disease.
Variable Definitions
We used the presence of any CD4 or viral load report in the registry to indicate a care visit.9 We defined retention in care as 1 or more visits in a calendar year, retention in continuous care (also known as “engagement in care”) as 2 or more visits at least 3 months apart in a calendar year, and viral suppression as a viral load value of less than 400 copies per milliliter on the last viral load measure of the calendar year.27 Covariates included in the analyses were gender, age, race/ethnicity, transmission risk, area of birth, and clinical status. These variables followed conventions established by the CDC for state and local surveillance reporting.17,27 We classified gender as male or female. We classified current age in years (as of December 31 of each calendar year) as birth to 12 years, 13 to 19 years, 10-year age groups from 20 to 59 years, and 60 years and older. We classified race/ethnicity as Hispanic for persons of any race who were of Hispanic ethnicity and according to race for all others. Transmission risk was the likely mode of HIV transmission as documented in the patient’s medical record. We classified area of birth as United States, United States dependency, foreign country, or unknown. We dichotomized clinical status as ever diagnosed with AIDS or with HIV infection only (non-AIDS) by the end of each calendar year.
Statistical Analysis
We included all 5-year data in the trends analysis of the proportions of persons retained in care, retained in continuous care, and virally suppressed from 2006 to 2010 in NYC. We used 1-year data on patients diagnosed, reported, and living in NYC as of December 31, 2010 to (1) describe care and viral suppression status among NYC PLWHA by demographic and clinical characteristics and (2) estimate adjusted prevalence ratios (APRs) and 95% confidence intervals (CIs) for retention in care and viral suppression from log-binominal models, using gender, age, race/ethnicity, transmission risk, area of birth, and clinical status as the independent variables. Because of the large sample size (> 80 000), we judged significant differences on the basis of both statistical significance (P < .05) and practical importance (≥ 5% difference in APR). We conducted all analyses using SAS version 9.2 (SAS Institute, Cary, NC).
RESULTS
We estimated that between the years 2006 and 2010, there were 80 547, 82 357, 84 091, 85 615, and 87 146 PLWHA in NYC, respectively. The proportion of patients retained in care was essentially stable over the analysis period, with 82.5% in 2006 and 81.8% in 2010; the proportion of patients retained in continuous care was also stable, with 67.5% in 2006 and 68.5% in 2010. By contrast, the proportion of persons with evidence of viral suppression increased significantly, from 44.3% to 59.1%, during the same period (Figure 1).
FIGURE 1—
Proportions of persons living with HIV/AIDS who were retained in care, retained in continuous care, or virally suppressed: New York City, 2006–2010.
Demographic and Clinical Characteristics
The population of PLWHA in NYC as of the end of 2010 was 70.4% male and 29.6% female, 45.3% Black and 32.6% Hispanic, and 34.8% aged 40 to 49 years and 28.0% aged 50 to 59 years. Fifty-nine percent had ever been diagnosed with AIDS, and 41.0% had been diagnosed with HIV infection only (Table 1).
TABLE 1—
Proportions of Persons Living With HIV/AIDS Who Were Retained in Care, Retained in Continuous Care, or Virally Suppressed, by Demographic and Clinical Characteristics: New York City, 2010
| Characteristic | Total, No. (Column %) | Retained in Care (≥ 1 Care Visit), No. (Row %) | Retained in Continuous Care (≥ 2 Care Visits, 3 mo Apart), No. (Row %) | Virally Suppressed (< 400 Copies/mL), No. (Row %) |
| Total | 87 146 (100.0) | 71 255 (81.8) | 59 664 (68.5) | 51 504 (59.1) |
| Gender | ||||
| Male | 61 344 (70.4) | 49 574 (80.8) | 41 130 (67.0) | 36 387 (59.3) |
| Female | 25 802 (29.6) | 21 681 (84.0) | 18 534 (71.8) | 15 117 (58.6) |
| Race/ethnicity | ||||
| Black | 39 488 (45.3) | 32 057 (81.2) | 26 566 (67.3) | 21 705 (55.0) |
| Hispanic | 28 445 (32.6) | 23 848 (83.8) | 20 648 (72.6) | 17 274 (60.7) |
| White | 17 254 (19.8) | 13 748 (79.7) | 11 091 (64.3) | 11 245 (65.2) |
| Asian/Pacific Islander | 1497 (1.7) | 1218 (81.4) | 1032 (68.9) | 987 (65.9) |
| Native American | 233 (0.3) | 200 (85.8) | 175 (75.1) | 141 (60.5) |
| Multiracial | 46 (0.1) | 36 (78.3) | 30 (65.2) | 25 (54.3) |
| Unknown | 183 (0.2) | 148 (80.9) | 122 (66.7) | 127 (69.4) |
| Age group, y | ||||
| Birth–12 | 273 (0.3) | 242 (88.6) | 226 (82.8) | 158 (57.9) |
| 13–19 | 1070 (1.2) | 924 (86.4) | 811 (75.8) | 518 (48.4) |
| 20–29 | 7253 (8.3) | 5402 (74.5) | 3974 (54.8) | 2883 (39.7) |
| 30–39 | 13 932 (16.0) | 10 613 (76.2) | 8441 (60.6) | 7010 (50.3) |
| 40–49 | 30 335 (34.8) | 24 776 (81.7) | 20 704 (68.3) | 17 670 (58.2) |
| 50–59 | 24 436 (28.0) | 20 845 (85.3) | 18 033 (73.8) | 16 132 (66.0) |
| ≥ 60 | 9847 (11.3) | 8453 (85.8) | 7475 (75.9) | 7133 (72.4) |
| Transmission risk | ||||
| MSM | 30 931 (35.5) | 24 983 (80.8) | 20 374 (65.9) | 18 901 (61.1) |
| IDU | 14 616 (16.8) | 12 503 (85.5) | 11 012 (75.3) | 8510 (58.2) |
| Heterosexual | 18 351 (21.1) | 15 214 (82.9) | 12 809 (69.8) | 10 747 (58.6) |
| Perinatal | 1827 (2.1) | 1606 (87.9) | 1436 (78.6) | 917 (50.2) |
| Other or unknown | 21 421 (24.6) | 16 949 (79.1) | 14 033 (65.5) | 12 429 (58.0) |
| Area of birth | ||||
| United States | 49 415 (56.7) | 40 414 (81.8) | 33 599 (68.0) | 28 012 (56.7) |
| US dependency | 4754 (5.5) | 4004 (84.2) | 3502 (73.7) | 2675 (56.3) |
| Foreign | 15 571 (17.9) | 12 581 (80.8) | 10 640 (68.3) | 9 624 (61.8) |
| Unknown | 17 406 (20.0) | 14 256 (81.9) | 11 923 (68.5) | 11 193 (64.3) |
| Clinical status | ||||
| HIV (non-AIDS) | 35 731 (41.0) | 26 353 (73.8) | 20 913 (58.5) | 18 078 (50.6) |
| AIDS | 51 415 (59.0) | 44 902 (87.3) | 38 751 (75.4) | 33 426 (65.0) |
Note. IDU = injection drug user; MSM = men who have sex with men.
Overall, 81.8% of PLWHA were retained in care in 2010 and 68.5% retained in continuous care. Females were more likely to be retained in care (84.0% vs 80.8%) and in continuous care (71.8% vs 67.0%) than males. Age at both ends of life was associated with high proportions retained in care (e.g., aged birth–12 years: 88.6%; aged 20–29 years: 74.5%; aged ≥ 60 years: 85.8%) and in continuous care (e.g., aged birth–12 years: 82.8%; aged 20–29 years: 54.8%; aged ≥ 60 years: 75.9%). Patients with perinatal transmission risk had the highest proportions retained in care (87.9%) and in continuous care (78.6%), followed by injection drug users, with 85.5% retained in care and 75.3% in continuous care. Patients with AIDS were significantly more likely than those with HIV non-AIDS to be retained in care (87.3% vs 73.8%) and in continuous care (75.4% vs 58.5%; Table 1).
Overall, 59.1% of PLWHA in NYC were virally suppressed in 2010. By race/ethnicity, Blacks had the lowest proportion (55.0%) with viral suppression, and Whites (65.2%) and Asians/Pacific Islanders (65.9%) had the highest; persons in the 20- to 29-year age group had the lowest viral suppression proportion (39.7%), and persons aged 60 years or older had the highest (72.4%); patients with perinatal transmission risk were least likely to have a suppressed viral load (50.2%; Table 1).
Multivariable Analysis of Retention in Care and Viral Suppression
The multivariable logistic regression analysis showed that there were significant differences in retention in care and continuous care by age and clinical status. Compared with the 20- to 29-year age group, persons aged birth to 12 years (APR = 1.16; 95% CI = 1.13, 1.20), 13 to 19 years (APR = 1.13; 95% CI = 1.10, 1.15), 50 to 59 years (APR = 1.07; 95% CI = 1.06, 1.09), and 60 years or older (APR = 1.08; 95% CI = 1.07, 1.10) were more likely to be retained in care, and even more likely to be in continuous care (APR = 1.45 [95% CI = 1.40, 1.51], 1.31 [95% CI = 1.27, 1.36], 1.22 [95% CI = 1.20, 1.25], and 1.26 [95% CI = 1.23, 1.29], respectively). Persons with AIDS diagnoses were more likely to be retained in care (APR = 1.16; 95% CI = 1.15, 1.17) and in continuous care (APR = 1.22; 95% CI = 1.21, 1.23). There were no significant differences in retention in care by gender, transmission risk, or area of birth, and no differences in continuous care by transmission risk or area of birth (Table 2). Males were slightly less likely to be in continuous care than females (APR = 0.94; 95% CI = 0.93, 0.95).
TABLE 2—
Factors Associated With Retention in Care, Retention in Continuous Care, and Viral Suppression Among Persons Living With HIV/AIDS: New York City, 2010
| Retained in Care (≥ 1 Care Visit) |
Retained in Continuous Care (≥ 2 Care Visits, 3 Months Apart) |
Virally Suppressed (< 400 Copies/mL) |
||||||||||
| Variable | Crude PR (95% CI) | P | APR (95% CI) | P | Crude PR (95% CI) | P | APR (95% CI) | P | Crude PR (95% CI) | P | APR (95% CI) | P |
| Gender | ||||||||||||
| Male | 0.96 (0.95, 0.97) | < .001 | 0.96 (0.95, 0.97) | < .001 | 0.93 (0.92, 0.94) | < .001 | 0.94 (0.93, 0.95) | < .001 | 1.01 (1.00, 1.02) | .09 | 0.96 (0.94, 0.97) | < .001 |
| Female (Ref) | 1.00 | . . . | 1.00 | . . . | 1.00 | . . . | 1.00 | . . . | 1.00 | . . . | 1.00 | . . . |
| Race/ethnicity | ||||||||||||
| Black | 1.02 (1.01, 1.03) | < .001 | 1.03 (1.02, 1.03) | < .001 | 1.05 (1.03, 1.06) | < .001 | 1.04 (1.03, 1.06) | < .001 | 0.84 (0.83, 0.86) | < .001 | 0.89 (0.87, 0.90) | < .001 |
| Hispanic | 1.05 (1.05, 1.06) | < .001 | 1.05 (1.04, 1.06) | < .001 | 1.13 (1.12, 1.15) | < .001 | 1.11 (1.10, 1.13) | < .001 | 0.93 (0.92, 0.95) | < .001 | 0.98 (0.97, 1.00) | .02 |
| White (Ref) | 1.00 | . . . | 1.00 | . . . | 1.00 | . . . | 1.00 | . . . | 1.00 | . . . | 1.00 | . . . |
| Asian/Pacific Islander | 1.02 (0.99, 1.04) | .2 | 1.05 (1.02, 1.07) | < .001 | 1.07 (1.03, 1.11) | < .001 | 1.10 (1.06, 1.13) | < .001 | 1.01 (0.97, 1.05) | .69 | 1.03 (1.00, 1.07) | .06 |
| Other or unknown | 1.05 (1.00, 1.09) | .03 | 1.06 (1.02, 1.10) | < .01 | 1.10 (1.04, 1.17) | < .01 | 1.13 (1.07, 1.19) | < .001 | 0.97 (0.91, 1.04) | .44 | 1.03 (0.96, 1.09) | .42 |
| Age group, y | ||||||||||||
| Birth–12 | 1.20 (1.15, 1.26) | < .001 | 1.16 (1.13, 1.20) | < .001 | 1.53 (1.44, 1.62) | < .001 | 1.45 (1.40, 1.51) | < .001 | 1.48 (1.33, 1.64) | < .001 | 1.58 (1.43, 1.76) | < .001 |
| 13–19 | 1.17 (1.13, 1.20) | < .001 | 1.13 (1.10, 1.15) | < .001 | 1.39 (1.33, 1.45) | < .001 | 1.31 (1.27, 1.36) | < .001 | 1.23 (1.15, 1.31) | < .001 | 1.23 (1.15, 1.32) | < .001 |
| 20–29 (Ref) | 1.00 | . . . | 1.00 | . . . | 1.00 | . . . | 1.00 | . . . | 1.00 | . . . | 1.00 | . . . |
| 30–39 | 1.03 (1.01, 1.05) | < .001 | 1.00 (0.98, 1.01) | .86 | 1.12 (1.09, 1.14) | < .001 | 1.06 (1.04, 1.09) | < .001 | 1.28 (1.24, 1.32) | < .001 | 1.22 (1.18, 1.26) | < .001 |
| 40–49 | 1.11 (1.09, 1.13) | < .001 | 1.04 (1.03, 1.06) | < .001 | 1.26 (1.23, 1.29) | < .001 | 1.16 (1.13, 1.18) | < .001 | 1.49 (1.44, 1.53) | < .001 | 1.39 (1.35, 1.43) | < .001 |
| 50–59 | 1.16 (1.14, 1.18) | < .001 | 1.07 (1.06, 1.09) | < .001 | 1.37 (1.33, 1.40) | < .001 | 1.22 (1.20, 1.25) | < .001 | 1.69 (1.64, 1.74) | < .001 | 1.57 (1.52, 1.62) | < .001 |
| ≥ 60 | 1.17 (1.15, 1.19) | < .001 | 1.08 (1.07, 1.10) | < .001 | 1.41 (1.37, 1.44) | < .001 | 1.26 (1.23, 1.29) | < .001 | 1.85 (1.80, 1.91) | < .001 | 1.69 (1.64, 1.75) | < .001 |
| Transmission risk | ||||||||||||
| MSM (Ref) | 1.00 | . . . | 1.00 | . . . | 1.00 | . . . | 1.00 | . . . | 1.00 | . . . | 1.00 | . . . |
| IDU | 1.07 (1.06, 1.07) | < .001 | 0.99 (0.98, 1.00) | < .01 | 1.15 (1.14, 1.17) | < .001 | 1.00 (0.99, 1.02) | .62 | 0.96 (0.94, 0.97) | < .001 | 0.87 (0.85, 0.88) | < .001 |
| Heterosexual | 1.03 (1.02, 1.04) | < .001 | 0.97 (0.96, 0.98) | < .001 | 1.06 (1.05, 1.08) | < .001 | 0.96 (0.95, 0.97) | < .001 | 0.96 (0.95, 0.98) | < .001 | 0.92 (0.90, 0.93) | < .001 |
| Other or unknown | 0.99 (0.98, 1.00) | .04 | 0.96 (0.95, 0.97) | < .001 | 1.01 (1.00, 1.03) | < .05 | 0.95 (0.94, 0.96) | < .001 | 0.94 (0.93, 0.96) | < .001 | 0.91 (0.90, 0.93) | < .001 |
| Area of birth | ||||||||||||
| United State (Ref) | 1.00 | . . . | 1.00 | . . . | 1.00 | . . . | 1.00 | . . . | 1.00 | . . . | 1.00 | . . . |
| US dependency | 1.04 (1.02, 1.05) | < .001 | 0.99 (0.97, 1.00) | .02 | 1.09 (1.07, 1.11) | < .001 | 0.98 (0.97, 1.00) | .05 | 0.99 (0.97, 1.02) | .68 | 0.93 (0.91, 0.96) | < .001 |
| Foreign | 0.99 (0.98, 1.00) | < .01 | 0.99 (0.98, 1.00) | .03 | 1.00 (0.99, 1.02) | .5 | 1.00 (0.99, 1.01) | .72 | 1.09 (1.07, 1.11) | < .001 | 1.08 (1.06, 1.09) | < .001 |
| Unknown | 1.00 (0.99, 1.01) | .49 | 0.99 (0.98, 1.00) | .02 | 1.01 (1.00, 1.02) | .09 | 0.99 (0.97, 1.00) | < .01 | 1.14 (1.13, 1.16) | < .001 | 1.06 (1.05, 1.07) | < .001 |
| Clinical status | ||||||||||||
| HIV (non-AIDS) (Ref) | 1.00 | . . . | 1.00 | . . . | 1.00 | . . . | 1.00 | . . . | 1.00 | . . . | 1.00 | . . . |
| AIDS | 1.19 (1.18, 1.20) | < .001 | 1.16 (1.15, 1.17) | < .001 | 1.24 (1.23, 1.25) | < .001 | 1.22 (1.21, 1.23) | < .001 | 1.29 (1.28, 1.31) | < .001 | 1.22 (1.20, 1.23) | < .001 |
Note. APR = adjusted prevalence ratio; CI = confidence interval; IDU = injection drug user; MSM = men who have sex with men; PR = prevalence ratio.
The multivariable analysis of viral suppression showed that Blacks were least likely to have a suppressed viral load (APR = 0.89 vs Whites; 95% CI = 0.87, 0.90). Compared with men who have sex with men, injection drug users (APR = 0.87; 95% CI = 0.85, 0.88) and heterosexuals (APR = 0.92; 95% CI = 0.90, 0.93) were less likely to be virally suppressed. There was a U-shaped relationship between age and viral suppression, with the 20- to 29-year age group least likely to have a suppressed viral load and the birth to 12-year age group (APR = 1.58; 95% CI = 1.43, 1.76) and the 60 years and older age group (APR = 1.69; 95% CI = 1.64, 1.75) most likely to be suppressed.
DISCUSSION
Using a previously described laboratory surveillance method, we estimated the proportions of PLWHA in NYC that were retained in care and virally suppressed. These estimates were higher than the national estimates17,27,28 and higher than those we would calculate using a conventional denominator composed of all persons diagnosed and reported in NYC and not known to be dead or to have moved out of jurisdiction. Our better-than-national results may be partly explained by wider availability and accessibility of HIV care in NYC as well as early uptake of early ART by physicians and patients, but they are equally or perhaps more likely attributable to the different methodology we used to generate a more accurate, realistic estimate of our PLWHA denominator.
Why does this approach work in NYC? The city has comprehensive electronic reporting of HIV-related laboratory tests as well as names, including aliases, and other unique identifiers that significantly improve the accuracy of matching and deduplication over that possible at the national level. Moreover, care in NYC is highly accessible. The city has 32 Designated AIDS Centers (multidisciplinary hospitals with experience and expertise in HIV diagnosis and care) and hundreds of free-standing clinics, the majority located in the neighborhoods with the heaviest burden of disease. All Designated AIDS Centers are readily accessible via a public transportation system that may be the best in the United States. New York State’s public benefit package ensures that no one goes without HIV care or ART because of lack of resources, and coverage is available to all regardless of citizenship or immigration status. The benefits extend beyond care and treatment to housing, nutrition, entitlements advocacy, and legal assistance. The city health department identifies and offers case management and assistance with return to care to persons with a care hiatus of 9 months or more.29 Identifying the relative contributions of problems with access to care or continuity of ART supply, patient compliance, and natural progression of disease despite appropriate therapy would allow us to focus on the range of problems that require interventions and to prioritize appropriate services to those in greatest need.
Local health departments conduct routine registry matches to ascertain deaths among PLWHA, but they have limited means to identify patients who have died outside the United States or migrated out of jurisdiction after diagnosis or since the last time they received HIV care. The CDC sponsors a process entitled Routine Interstate Duplicate Review to deduplicate cases across the states based on Soundex, a phonetic algorithm for indexing names.30 However, this process is imperfect. Patients with duplicate records that at the time of this analysis had not yet been detected and removed or reconciled would have at least 1 record that made them appear to be out of care. During death registry matching, patients who have died may also be missed because of inconsistencies in names and other matching variables or death outside of the United States or US dependencies; these patients would be mistakenly classified as out of care and virally unsuppressed.31 Failure to remove patients who have migrated out of the jurisdiction or died would overestimate the denominator (i.e., the number of PLWHA) and underestimate the proportions of patients retained in care and virally suppressed.
In our analyses, we removed patients from the denominator who had no HIV-related tests in the past 5 years. In doing so, we have reported higher proportions of patients retained in care and virally suppressed than national estimates17,26–28 and the proportions that we calculated using a conventional denominator. Given the natural history of HIV infection and wide availability of HIV care in the United States and NYC,23 few patients will be able to stay out of care for 5 or more years, particularly in NYC, where 60% of PLWHA have AIDS and more than half of all newly diagnosed persons have already reached the 2006 to 2010 federal treatment thresholds. Our estimates of the denominator and proportions of patients retained in care and virally suppressed may thus be more plausible.
NYC experienced stable rates of retention in care but significant increases in viral suppression from 2006 through 2010. Stable rates of retention in care may suggest little improvement over time in engaging out-of-care patients into HIV care; improvements in viral suppression may be a result of increasingly early uptake of ART in NYC, an expanded formulary, drugs with better bioavailability, simpler dosing schedules, and improved adherence support.
Our analysis has limitations. First, the method depends on the quality and completeness of HIV-related laboratory data reporting. The surveillance registry is continuously updated with new laboratory and vital events so that ascertainment of care and vital status is virtually complete. Undercounting of events can occur because of inconsistencies in names and other matching variables, such as name change and missing social security number. These issues are endemic to surveillance systems and are the driving force behind every jurisdiction’s heavy emphasis on and investment of time and personnel in quality control. A recent internal review comparing electronic laboratory reporting with medical record abstraction showed more than 97% concordance. Because only in-care patients can be missed by incomplete laboratory reporting (out-of-care patients by definition have no HIV-related tests to report), incomplete reporting would result in underestimates of our outcomes; that is, the actual proportions of patients retained in care and virally suppressed may be even higher than estimated.
Second, we considered patients with no HIV-related tests in the past 5 years to be no longer living in NYC and removed them from the denominator. Some patients may be able to stay out of care for more than 5 years. Misclassifying these persons as out of jurisdiction would underestimate the denominator and overestimate the proportions retained in care and virally suppressed. We tested the return rate after a 5-year absence. Only 834 (3.3%) of the 25 154 PLWHA with no laboratory tests during the 5-year period 2006 through 2010 returned for care in 2011 through 2012. If we had reinstated them into the population, they would have accounted for only 0.9% of the total percentage of PLWHA in NYC as of the end of 2010 (834/[87 146 + 834] = 0.9%). The proportions of persons retained in care and virally suppressed would only decrease from 81.8% to 81.0% and from 59.1% to 58.6%, respectively.
Third, our inclusion of all persons who had at least 1 HIV-related test in the past 5 years in the denominator may misclassify some out-of-jurisdiction individuals as living in NYC but out of care. For example, a patient who last had a test in NYC in 2006 would be included in the denominator for the calendar year 2010 analysis, despite the fact that the patient had no HIV-related tests in NYC for the 4 years between 2007 and 2010. The 2010 US Census reported that 39% of individuals moved out of their county in the previous 5 years.32 Although HIV-infected persons may be less likely to migrate than HIV-negative individuals, there still could be a substantial number of patients who migrated out of jurisdiction after diagnosis or the last time they received care.33 By mistakenly including these patients in the denominator, we would underestimate the proportions of patients retained in care and virally suppressed in NYC. The true proportions would be even higher than estimated.
Fourth is the absence of ART information in the HIV registry. We argue that although ART data are needed to measure the success of ART, they are not needed for this analysis, whose focus is on population viral suppression. Under current federal guidelines and NYC recommendations to treat all HIV-infected individuals, regardless of CD4 count, many more patients in care after 2012 will likely have been offered ART compared with those analyzed in this report.7,34 Surveillance is reviewing the feasibility of periodic medical record reabstraction to capture information ART.
Using a method that removed patients who were likely to have migrated out of jurisdiction after diagnosis or the last time they received care, we reported higher and more plausible proportions of patients retained in care and virally suppressed in NYC. The stable trend in retention in care means that the city continues to face the challenge of engaging or reengaging thousands of out-of-care New Yorkers. Persons who are out of care are at higher risk for HIV-related morbidity and mortality and for transmitting the virus to others because of unsuppressed HIV viral load.1,35 To improve the length and quality of life of PLWHA and to reduce secondary transmission, NYC needs innovative intervention programs to reengage out-of-care patients.29 Although the overall proportion with viral suppression has been steadily increasing, some subgroups (e.g., younger patients, Blacks, and injection drug users) consistently have higher proportions with viremia. Although ART adherence support should be offered to all persons in care, special emphasis may be needed for subgroups facing special challenges.
We suggest that each jurisdiction, when preparing to use surveillance data for measuring NHAS outcomes, evaluate the accuracy and completeness of its surveillance system and explore methods that most accurately count patients who are still living in the jurisdiction. These will become increasingly important as surveillance and policymakers enter the era of universal treatment and must monitor outcomes such as viral suppression and reduced incidence that represent true epidemic control.
Acknowledgments
This study was supported in part by a Cooperative Agreement with the Centers for Disease Control and Prevention (PS08-80202, #UC62/CCU223595).
This work was presented in part at the Conference on Retroviruses and Opportunistic Infections; March 3–6, 2014; Boston, MA (abstract 890).
Human Participant Protection
This study was an analysis of routinely collected New York City population surveillance data and as such did not require human participant review.
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