Concordance of HIV surveillance and medical record data: What do CD4 and viral loads not tell us about

linkage to HIV care?

Charu Sabharwal, MD MPHMedical DirectorEpidemiology and Field Services ProgramBureau of HIV/AIDS Prevention and ControlNYC Department of Health

Acknowledgements• Sarah Braunstein• Rebekkah Robbins• Colin Shepard• HIV Epidemiology and Field Services Program

Background

• NHAS (July, 2010) - first comprehensive roadmap

• A more coordinated response to the HIV epidemic

• Primary Goals for 2015:– Reduce infections– Increase access to care– Reduce health disparities

National HIV/AIDS Strategy

HIV Continuum of Care

Das, Moupali Prevention of HIV Acquisition: Behavioral, Biomedical, and Other Interventions. Medscape 2012

• HIV Care = outpatient HIV visit with provider authorized to prescribe ART1

• Clinical monitoring/treatment guidelines2 – Traditionally, 1st CD4/VL at initial HIV care visit– CD4/VL: every 3-6 months; frequency after ART initiation

• CD4/VLs proxy for HIV care [HIV care visits not reported]• Since 2004, CSTE encouraged all states (59

jurisdictions) to report all CD4 and VLs3 [New York2005]

• Limited comprehensive evaluation of the validity of surveillance data as proxy of HIV care

Monitoring HIV Care – CD4/VL

1Health Resources and Services Administration. The HIV/AIDS Program: HAB Performance Measures Group 1. In; 2009. 2DHHS Guidelines for the Use of Antiretroviral Agents in HIV-1-Infected Adults and Adolescents. In; 2012. 3 CSTE Position statement 04-ID-07

• Surveillance traditionally measures linkage by a single event: 1st reported CD4/VL on/after HIV diagnosis date

• Accuracy of 1st CD4/VL1,2 drawn prior to referral to HIV care. For example, at the time of– Confirmatory testing after + rapid/point-of-care test – Inpatient diagnosis: CD4 impacts treatment decision

• In New York City: routine medical record (MR) abstraction for linkage to care is not feasible– 3,500 diagnosing providers; 3,000+ HIV cases yearly– Timely linkage – entry into care within 3 months of

diagnosis. Local3 and national measure

Measuring linkage to care

1 Bertolli A. et al The Open AIDS Journal 2012,6:131-141. 2Keller et al. J Acquir Immune Defic Syndr 2013. 3New York City HIV/AIDS Surveillance Slide Sets. http://www.nyc.gov/html/doh/html/data/epi-surveillance.shtml

New York City’s Care Validation Study

• Validate CD4 and VL tests for persons living with HIV (PLWH) in NYC as proxy measure for HIV care in the first year after diagnosis

1° Objective – evaluate the correspondence

between a patients 1st CD4/VL on/after HIV diagnosis and linkage HIV care

PurposeValidate 1st lab test (CD4/VL) from the diagnosing facility as measure of timely linkage to HIV care • Hypothesis: early post-diagnostic lab

tests within first 2 weeks are part of diagnostic work-up and not an actual linkage event

Methods

Methods

• Selected high-volume HIV diagnosing sites with co-located care (n=24) –Patients with new, confirmed HIV diagnosis

in 2009 reported the Registry–Patients who had to linked to care at the

same diagnosing facility within 12 months as per the Registry • PLEASE NOTE – Even though Surveillance does not

require linkage to care at the same site of diagnosis, we did in order to conduct this validation study

Study population selection: New York City HIV Registry

3,536 new, confirmed HIV diagnoses among > 13 years in NYC in 2009

1,263 (36%) patients reported from high-volume (> 20 diagnoses) co-located HIV care sites

947 (75%) patients had 1st CD4/VL reported from co-located site within 12 months of diagnosis

eligible for medical record (MR) abstractions

165 (17%) excluded: MR unavailable

Figure 1: Final study population

782 (83%) patients Registry (1st CD/VL) and MR (care visit) data

Data Analysis

Analytic population (n=782)Linkage within 12 months, per Registry

No medical visit group Medical visit group

HIV care visit confirmed by MR

Compared the subgroups based on:• Key demographic characteristics (age, gender, risk)• Proportion concurrently diagnosed with HIV/AIDS

(AIDS within 31 days of HIV diagnosis – local definition)• Proportion diagnosed on inpatient service• Proportion that died within 12 months of diagnosis

YESNO

Timely linkage to HIV care

• Compared the proportion who linked to HIV care within 3 months of diagnosis (timely) by Registry (1st CD/VL) vs. MR (care visit)

Do 1st reported CD4/VLs indicate timely linkage to HIV care?

• Compared subgroups:– Median time to 1st lab per the Registry– Proportion of 1st labs in 0-7 days and 0-14 days

• Calculated sensitivity, specificity, positive predictive value (PPV), negative predictive value (NPV) of Registry data in correctly classifying patients’ true timely linkage to care status based on the 1st CD/VL within:– 0-91 days (no labs excluded: National standard)– 8-91 days (excluded labs from 0-7 days)– 15-91 days (excluded labs from 0-14 days)

RESULTS

Figure 2: Linkage to care (n=782)Registry vs. MR

Registry MR0%

20%

40%

60%

80%

100%

% L

inke

d to

care

with

in

12 m

onth

s of d

iagn

osis

Medical visit80% (n=625)

1st CD4/VL100% (n=782)

No Medical visit20% (n=157)

No medical visit

N=157

Medical visit

N=625 P value

Age at HIV diagnosis (median, range) 42 (16-80) 37 (15-78) 0.001

Male Gender (%) 69.4 74.2 0.220

Race/ethnicity (%)

Black 54.1 48.0 0.370

Hispanic 36.9 37.4

White 7.6 11.0

Transmission risk (%)

Men who have sex with men 18.5 42.9 <0.001

Injection drug use 8.9 4.2

Heterosexual 33.8 29.3

No identified risk 38.9 23.7

Concurrent AIDS diagnosis 61.8 37.0 <0.001

Table 1: Demographics/clinical outcomes

Figure 3: Inpatient diagnoses

Diagnosed in acute setting0%

20%

40%

60%

80%

100%

73%

32%

% S

tudy

pop

ulati

on

p<0.001

No medical visit Medical visit

Figure 4: Mortality outcomes:Deaths within 12 months of HIV diagnosis

No medical visit Medical visit0

5

10

15

20

18%

1 %

% D

ied

with

in 1

2 m

onth

s of H

IV d

i-ag

nosi

s

p<0.001

Timely Linkage to Care

Figure 5: Timely linkage to careRegistry vs. MR

Registry MR0%

20%

40%

60%

80%

100%

% L

inke

d to

care

with

in

12 m

onth

s of d

iagn

osis

97%

1st CD4/VL(proxy measure):

0-91 days

75%

True linkage event(HIV care visit):

0-91 days

Timely linkageAre labs within the early

post-diagnostic period indicative of timely linkage to care?

Figure 6: Median time (days) to linkage based on 1st CD4/VL, by subgroups

MR0%

20%

40%

60%

80%

100%

% L

inke

d to

care

with

in 1

2 m

onth

s of d

iagn

osis

8 days (IQR 0-20days)

1 day (IQR 0-5 days)No medical visit

Medical visit

p <0.001

Figure 7: Proportion of 1st labs in the early post-diagnostic period, by subgroups

0 - 7 days 0 - 14 days0%

20%

40%

60%

80%

100%

80% 85%

49%66%

% P

atien

ts w

ith fi

rst l

ab o

ccur

ing

in

time

perio

d

No medical

visit

No medical

visit Medical

visit Medical

visit

p <0.001p <0.001

31%

19%

Sensitivity Specificity PPV NPV0%

20%

40%

60%

80%

100%

84%

24%

76%

33%

73%

23%

73%

22%

11%

77%

96%99%

0-91 days 8-91 days 15-91 days

Figure 8: Performance of Registry data

Refinement of NYC’s timely linkage to care indicator

Figure 9: Final study population: Refining timely linkage to care

Study population0

20

40

60

80

100 97%

81%75%

% L

inke

d tim

ely

(with

in 3

m

onth

s) to

care

Gold standard: care visit

Lag applied

No lag applied

Figure 10: New York City’s refined Timely linkage to care indicator

All new 2009 diagnoses All new 2010 diagnoses0

20

40

60

80

100

75% 73%66% 66%

% L

inke

d tim

ely

to ca

re

No lagLag

No lagLag

Conclusions• First population-based study to validate the use of HIV

Surveillance’s proxy measure of timely linkage to care• Substantial misclassification of timely linkage in the

early post-diagnostic period • NYC DOHMH implemented a refined definition of

timely linkage to care (labs 8-91 days after diagnosis)– HIV labs in 1st 7 days not indicative of linkage

• Surveillance data overestimated linkage for older persons, non-traditional HIV risk transmission, and those who died soon after diagnosis

Limitations• Selection of provider– A portion had a CD4/VL at an alternate provider which may

be the linkage to care visit –DID NOT validate if these patients EVER linked

– Oversampled the acute care setting

• Selection of study population – Due to the complexities of HIV laboratory reporting, the

1st lab may have been misclassified to the incorrect provider

Future directions• Exploration of surveillance-based retention in

care measures vs. medical abstraction data– All care visits at diagnosing provider during first 12

months immediately following diagnosis

• In depth exploration of mortality within 12 months of HIV diagnosis

cjain@health.nyc.gov

Thank you!