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Antiretroviral Therapy
Do Persons Living with HIV Continue to
Fill Prescriptions for Antiretroviral Drugs
during a Gap in Care? Analysis of a Large
Commercial Claims Database
Kathy K. Byrd, MD, MPH
1
, Tim Bush, MS
1
,
and Lytt I. Gardner, PhD
1
Abstract
The significance of a gap in HIV care depends, at least partially, on whether patients continue to fill prescriptions for antiretroviral
(ARV) drugs during the gap in care. We used a billing claims database to determine the proportion of persons who filled 1
prescription for ARV drugs during a gap in care (no clinic visit in >6 months). Persons were stratified into 3 groups: “never”
(prescriptions never filled), “sometimes” (prescriptions filled >0%-<100% of months), and “always” (prescriptions filled monthly).
Logistic regression analyses were conducted to determine factors associated with “never” filling ARV drugs. Of 14 308 persons,
69% (n ¼9817), 13% (n ¼1928), and 18% (n ¼2563) “never,” “sometimes,” and “always” filled ARV drugs during the gap in care.
Persons aged 18 to 29 years (odds ratio [OR] ¼1.56, 95% confidence interval [CI] 1.39-1.74), women (OR ¼1.67, CI 1.52-1.83),
and persons from the Northeast region of the United States (OR ¼1.86, CI 1.69-2.03) were more likely to never fill ARV drugs
than persons aged 30 years, men, and persons outside the Northeast, respectively. Efforts should be made to minimize gaps in
care, emphasize importance of therapy, and provide adherence support.
Keywords
HIV, AIDS, antiretroviral therapy, adherence, health care
Introduction
Retention in HIV care is associated with initiation of antire-
troviral (ARV) therapy (ART), viral suppression, reduced
mortality, and transmission risk.
1-4
Despite the importance
of being retained in care, in the United States, a substantial
proportion of persons living with HIV experience gaps in HIV
care (defined as no clinic visit in >6 months). In 2 recent
studies in the United States of publicly and commercially
insured persons with HIV, up to 30%experienced gaps in
care.
5,6
Although persons who have gaps in care are consid-
ered to be out of care, it is conceivable that some of these
individuals continue to fill ARV drug prescriptions, during
the gap, and could reach viral suppression.
In 2012, the US Department of Health Human Services
recommended that all persons living with HIV be prescribed
ART.
7
Because all persons living with HIV should be on ART,
ARV drug prescription filling behavior can indicate that a per-
son is engaged in care even if he or she has not recently been
seen by a clinic provider. The significance of a gap in HIV care
depends, at least partially, on whether patients continue to fill
ARV drug prescriptions during the gap. Information on filling
ARV drug prescriptions has seldom been evaluated in previous
studies of gaps in HIV care because of the lack of available
prescription data. We used a commercial claims database,
which contains pharmacy and diagnosis claims data, to deter-
mine whether persons who experienced gaps in HIV care con-
tinued to fill ARV drug prescriptions during the gap. To our
knowledge, this is the first analysis that examines filling of
ARV drug prescriptions during a gap in care.
Methods
We used the 2012 to 2014 Truven Health MarketScan Commer-
cial Claims and Encounters Databases (Truven Health) to deter-
mine the unweighted proportion of persons with HIV who
experienced a gap in care and who filled 1 prescription for an
ARV medication during each individual gap month. The datab ase
contains paid, patient-level health care, procedure, and pharmacy
billing claims from inpatient and outpatient services for active
1
Division of HIV/AIDSPrevention, Centers for Disease Control and Prevention,
Atlanta, GA, USA
Corresponding Author:
Kathy K. Byrd, Division of HIV/AIDS Prevention, Centers for Disease Control
and Prevention, 1600 Clifton Rd, MS E-45, Atlanta, GA, 30333, USA.
Email: gdn8@cdc.gov
Journal of the International
Association of Providers of AIDS Care
2017, Vol. 16(6) 632–638
ªThe Author(s) 2017
Reprints and permission:
sagepub.com/journalsPermissions.nav
DOI: 10.1177/2325957417729750
journals.sagepub.com/home/jia
employees, their spouses and dependents, early retirees, and
COBRA continuers insured by employer-sponsored plans in the
United States.
8
The 2012 MarketScan Commercial Claims and
Encounters Database included 53 131 420 unique enrollees.
Case Definition and Cohort Inclusion/Exclusion Criteria
Persons with HIV were identified using the 2012 MarketScan
database. A person was defined as having HIV if he or she had
an inpatient or outpatient service claim with 1 of the following
International Classification of Diseases, 9th Revision, Clinical
Modification (ICD-9 CM) diagnosis codes: 042, V08, 079.53,
and 795.71. An outpatient visit claim was defined using the
following Current Procedural Terminology (CPT) codes:
99201, 99202, 99203, 99204, 99205, 99212, 99213, 99214, and
99215. Antiretroviral drugs were defined using National Drug
Codes (http://www.accessdata.fda.gov/scripts/cder/ndc/
default.cfm). A gap in care was defined as no outpatient visit
claim with a physician, nurse practitioner, or physician assistant
in more than 6 months.
9
Persons who were 18 years of age in
2012, who had 1 gap in care that was 6monthsinlength
between 2012 and 2014, and who were continuously enrolled in
employer-sponsored insurance for the entire duration of the gap
were included in the analysis. Persons with gaps that were more
than 6 months in length were excluded because they were few in
number and the length of their gaps varied substantially. To
evaluate individual months of the gap, persons with ARV drug
prescriptions for more than a 30-day supply of medication were
excluded. Finally, persons who filled an ARV drug prescription
prior to the start of the gap, which covered part of the gap, were
also excluded. The final study sample included 14 308 persons.
Data Analysis
Analyses were restricted to each person’s first gap in care.Median
length of the gap was determined and stratified by age, sex, and
region of country. The Kruskal-Wallis test was used to determine
the difference between median gap length by characteristic. The
length of the gap in care was measured from 187 days after the last
clinic visit to the date of the next clinic visit. For each month
(30-day period) after day 187, we calculated the unweighted
proportion of persons who filled a prescription for at least 1 ARV.
We stratified persons into 3 groups based on how often they filled
an ARV drug prescription during the length of the gap: “never”
for persons who never filled an ARV drug prescription in any
month of the gap, “sometimes” for persons who filled a prescrip-
tion in >0%to <100%of the months, and “always” for persons
who filled an ARV drug prescription in every month of the gap.
Because 13%of persons who didn’t have a clinic visit in
>6 months (180 days) returned for a clinic visit by day 186, a
grace period of 7 days was given and the gap was calculated from
day 187 from the last clinic visit.
The proportion of persons who never, sometimes, or always
filled an ARV drug prescription were stratified by the length of
the gap. To determine whether the proportion of persons who
filled an ARV drug prescription changed as the length of the
gap increased, we conducted a w
2
test for trend in each cate-
gory. Because there were only 2 possible categories (never and
always) for filling an ARV drug prescription for persons with
gaps 1 month in length, we excluded persons with 1-month gap
when calculating the test for trend to keep all trends consistent.
The proportion of persons who never, sometimes, or always
filled an ARV drug prescription during their gap months was
also stratified by age, sex, and region of country; Pearson’s w
2
test was used to test for differences between groups. Race/
ethnicity data were not available in the MarketScan Commer-
cial Claims and Encounters Database.
Univariate and multivariable logistic regression analyses
were conducted to determine factors associated with increased
odds of never filling an ARV drug prescription in any gap
month; the outcome was never filling an ARV drug prescrip-
tion versus filling an ARV drug prescription sometimes or
always. We calculated odds ratios with 95%confidence inter-
vals (CIs), using age, sex, and region of country as explanatory
variables in the model. Backward selection was used for the
multivariable model.
10
All analyses were performed using SAS
9.3 (SAS Institute Inc).
Results
There were a total of 70 854 persons with HIV identified in the
2012 MarketScan Commercial Claims and Encounters Data-
base. Between 2012 and 2014, a total of 22 089 persons had a
gap in care, of whom 2774 had a gap >6 months in length. After
excluding persons with ARV drug prescriptions for >30-day
supply of medication (n ¼1783) and those with an ARV drug
prescription that overlapped the start of the gap (n ¼3224), a
total of 14 308 people were included in the study. The median
age was 44 years (interquartile range [IQR]: 36-50). Persons
aged 40 to 49 years made up the largest proportion of the
sample (38%). Seventy-eight percent of the sample was male
and 40%resided in the Southern United States (Table 1).
Characteristics of Gaps in Care
The median length of the first gap was 43 days (IQR: 20-85;
Table 1). Persons aged 18 to 29 years had the longest median
gap length at 54 (IQR: 25-101) days compared to each of the
older age-groups. Women had longer median gap length at 50
(IQR: 23-93) days than men; persons residing in the northeast
region had longer median gap length at 49 (IQR: 23-92) days
compared to persons residing in each of the other geographical
regions. Persons who sometimes filled an ARV drug prescrip-
tion had longer median gap length at 84 days (IQR: 16-78) than
persons who always (33 days [IQR: 21-65]) and never (36 days
[IQR: 16-78]) filled an ARV drug prescription.
Proportion of Persons Who Filled an ARV Drug
Prescription during the First Gap in Care
Overall, 69%(n ¼9,817), 13%(n ¼1,928), and 18%(n ¼2,563)
of persons never, sometimes, and always filled an ARV drug
Byrd et al 633
prescription during the gap (Table 2). Over 70%of persons
who sometimes filled an ARV drug prescription filled a
prescription in at least 50%of their gap months (data not
shown). Between 17%and 28%of the entire sample filled
an ARV drug prescription during any given gap month (data
not shown).
Between 60%and 78%of persons never filled an ARV drug
prescription in any gap month depending on the gap length.
After excluding gaps that lasted for 1 month, there was no
significant difference in the proportion of persons who never
filled an ARV drug prescription, as the length of the gap
increased. Between 20%and 33%of persons filled an ARV
drug prescription in some but not all months of the gap. The
proportion of persons who sometimes filled an ARV drug pre-
scription increased as the length of the gap increased (Pfor
trend .001). Between 7%and 22%of persons filled an ARV
drug prescription in every month. Forty-four percent of the
sample’s first gap was short at 7 to 30 days in length. After
excluding gaps that lasted for 1 month, the proportion of
persons who filled a prescription each month, throughout the
entire length of their gap, decreased as the gap length increased
(Pfor trend .001; Table 2).
Seventy-six percent of persons aged 18 to 29 years
(compared with 65%-69%for all other age-groups, all Pvalues
<.001), 77%of women (compared with 66%of men, P< .001),
and 78%of persons from the Northeast region (compared with
63%-67%for all other regions, all Pvalues <.001) never filled
an ARV drug prescription in any month of the gap (Table 3).
The proportion of persons who sometimes and always filled an
ARV drug prescription during the gap is presented, by charac-
teristic, in Table 3.
Factors Associated with Never Filling an ARV Drug
Prescription during the First Gap in Care
The results of the univariate and multivariable logistic regres-
sion analyses are presented in Table 4. On multivariable anal-
ysis, persons aged 18 to 29 years (OR ¼1.56, 95%CI 1.39-
1.74), women (OR ¼1.67, CI 1.52-1.83), and persons from the
Northeast region (OR ¼1.86, 1.69-2.03) were more likely to
never fill an ARV drug prescription during the gap than persons
aged 30 years, men, and persons from outside the Northeast
region, respectively (Table 4).
Discussion
Using a commercial claims database, we found that a substan-
tial proportion (69%) of persons living with HIV who had a gap
in HIV care failed to fill any ARV drug prescription throughout
the duration of the gap. Women, persons aged 18 to 29 years,
and persons residing in the Northeast region all had longer gap
duration and were all more likely to never fill an ARV drug
prescription compared to men, persons 30 years of age, and
persons residing in all other regions. While the proportion who
never filled an ARV drug prescription, during the gap,
remained stable regardless of the length of the gap, the propor-
tion of persons who always filled an ARV drug prescription
decreased as the length of the gap increased.
Studies found poor ART adherence to be associated with
low self-efficacy, current substance use, concerns about ART
safety, mistrust of the prescriber, stigma, poor health literacy,
and family responsibilities.
11-15
These factors may all play a
role in failing to fill ARV drug prescriptions during overly
long intervals between clinic visits. While nonadherence fac-
tors may be important, a less recognized reason for failing to
fillARVdrugprescriptions,duringagapincare,mightbea
lack of access. Although the Department of Health and
Human Services recommends that all persons living with HIV
be prescribed ART, it is possible that some individuals in this
study were never prescribed ART.
7
If true, the failure of such
an individual to fill an ARV drug prescription is an issue of
access rather that compliance. Another issue is the prescrip-
tion interval. Because a gap in care in this study starts at least
6 months after the last clinic visit, some in this study popu-
lation may not have had an active ARV drug prescription
during their gap and been unable to refill. The pattern of
filling prescriptions seen among the always group in this
study suggests this; the proportion of those who always filled
a prescription decreased as gap length increased. This pattern
may also represent treatment fatigue.
16
Women and younger persons were more likely to never fill
an ARV drug prescription during the gap in care. This finding
is congruent with the findings from several studies of lower
ART adherence among younger persons and women.
17-20
This
finding also follows a frequently reported trend of poorer reten-
tion in care and viral suppression among younger
persons.
5,17,21-23
Studies, however, have also shown that
younger persons are less likely to be prescribed ART, which
Table 1. Sample Demographics and Median Length of the First Gap in
Care.
n (%)
Median Gap Length,
Days (IQR)
a
Total 14 308 (100) 43 (20-85)
Age (years)
18-29 (referent) 1978 (14) 54 (25-101)
30-39 2871 (20) 48 (23-89)
b
40-49 5368 (38) 41 (19-82)
b
50 4091 (29) 37 (17-78)
b
Sex
Male (referent) 11 224 (78) 42 (19-83)
Female 3084 (22) 50 (23-93)
b
Region
Northeast (referent) 3488 (24) 49 (23-92)
North Central 2076 (15) 41 (20-81)
b
South 5785 (40) 40 (18-79)
b
West 2959 (21) 44 (20-91)
c
Abbreviation: IQR, interquartile range.
a
A gap in care was defined as no outpatient visit claim with a physician, nurse
practitioner, or physician assistant in more than 6 months. Length of the gap was
measured from 187 days after the last clinic visit to the date of the nextclinic visit.
b
Kruskal-Wallis test Pvalue of < .001.
c
Kruskal-Wallis test Pvalue of .015 comparing median gap length of the
referent to the West region.
634 Journal of the International Association of Providers of AIDS Care 16(6)
may account for some of the difference seen in our study.
24-27
Studies have shown mixed results regarding the proportion of
persons prescribed ARV drugs, by sex.
2,24,25,27
Both younger
persons and women had longer median gap length than older
persons and men which may amplify the failure to fill ARV
drug prescriptions during these gaps. Persons from the
Northeast region also were more likely to never fill an ARV
drug prescription during the gap. The reason for this finding
is unknown.
The definition of a gap in care used in this analysis was
based on the Department of Health and Human Services’ long-
est recommended intervisit interval of 6 months.
7
Some
Table 2. Proportion of Persons Who Filled 1 ARV during the First Gap in Care, by Length of the Gap and Frequency of the Action.
a
How often an ARV Was Filled during the Gap
Length of First Gap in Days
b
n
“Never”
c
(n ¼9817) “Sometimes”
c
(n ¼1928) “Always”
c
(n ¼2563)
n (%) n (%) n (%)
7-30 6325 4937 (78) n/a 1,388 (22)
31-60 3194 1968 (62) 638 (20)
d
588 (18)
d
61-90 1878 140 (61) 451 (24) 287 (15)
91-120 1304 811 (62) 344 (26) 149 (11)
121-150 991 594 (60) 292 (29) 105 (11)
151-180 616 367 (60) 203 (33) 46 (7)
Abbreviations: ARV, antiretroviral; n/a, not available.
a
N¼14 308.
b
Represents 30-day periods past 180 days from the last clinic visit. Because 13% of persons who didn’t have a clinic visit in >6 months (180 days) returnedfora
clinic visit by day 186, a grace period of 7 days was given and the gap started on day 187 from the last clinic visit. The first, 30-day period, therefore, represents days
7 to 30 after the start of the gap.
c
The frequency of having filled an ARV drug prescription during the gap was stratified into 3 groups: “never,” for persons who never filled an ARV drug
prescription in any month of the gap; “sometimes,” for persons who filled an ARV drug prescription in >0% to <100% of the months; and “always,” for persons
who filled an ARV drug prescription in every month of the gap.
d
After excluding gaps of 1 month in length, w
2
test for trend Pvalue of <.001.
Table 3. Proportion of Persons Who Filled 1 ARV Drug Prescription during the First Gap in Care, by Characteristic and Frequency of the
Action.
a
How often an ARV Was Filled during the Gap
n “Never”
b
(Total n ¼9817) “Sometimes”
b
(Total n ¼1928) “Always”
b
(Total n ¼2563)
Characteristic n (%) n (%) n (%)
Age, years
18-29 (referent) 1978 1499 (76)
c
227 (11) 252 (13)
c
30-39 2871 1971 (69) 414 (14)
d
486 (17)
40-49 5368 3507 (65) 790 (15)
e
1071 (20)
50 4091 2840 (69) 497 (12) 754 (18)
Sex
Male (referent) 11 224 7443 (66)
c
1,951 (14)
c
2190 (20)
c
Female 3084 2374 (77) 337 (11) 373 (12)
Region
Northeast (referent) 3488 2719 (78)
c
347 (10) 422 (12)
c
North Central 2076 1397 (67) 278 (13)
f
401 (19)
South 5,785 3822 (66) 833 (14)
e
1130 (20)
West 2959 1879 (63) 470 (16)
g
610 (21)
Abbreviation: ARV, antiretroviral.
a
N¼14 308.
b
The frequency of having filled an ARV drug prescription during the gap was stratified into 3 groups: “never,” for persons who never filled an ARV drug
prescription in any month of the gap; “sometimes,” for persons who filled an ARV drug prescription in >0% to <100% of the months; and “always,” for persons
who filled an ARV drug prescription in every month of the gap.
c
Pearson w
2
test Pvalue of <.001 comparing the referent to each characteristic within the “never,” “sometimes,” and “always” categories.
d
Pearson w
2
test Pvalue of .003 comparing persons aged 18 to 29 years to persons aged 30 to 39 years within the “sometimes” category.
e
Pearson w
2
test Pvalue of <.001 comparing persons aged 18 to 29 years to persons aged 40 to 49 years within the “sometimes” category.
f
Pearson w
2
test Pvalue of <.001 comparing persons from the Northeast region to persons residing each in the North central and South regions within the
“sometimes” category.
g
Pearson w
2
test Pvalue of .005 comparing persons from the Northeast region to persons residing in the West region.
Byrd et al 635
providers, however, might intentionally prolong the period
between scheduled appointments for patients who are stably
virally suppressed. Regardless of a person’s clinic visit sched-
ule, filling ARV drugs between visits might be considered a
measure of continued care. However, only 18%of persons,
within this analysis, filled ARV drug prescriptions consistently
between visits suggesting that a gap in care may be an indicator
of potential poor adherence.
For those prescribed ARV drugs, the failure to fill ARV
drug prescriptions during a gap in care is concerning because
suboptimal adherence can lead to inadequate viral suppres-
sion, increased transmission risk, and poor clinical outcomes
including increased morbidity and mortality.
28-32
An adher-
ence level of 70%to 95%is estimated to be necessary for viral
suppression, and studies have shown that even short treatment
interruptions can increase the risk of viral rebound.
31-38
A
study by Haberer et al found that the odds of viral rebound
increased by a factor of 1.25 for each day after 48 hours off
medication.
37
A study by Parienti et al found that the number
of treatment interruptions was associated with higher odds of
viral rebound.
36
While the majority of persons in our study
failed to ever fill a prescription during the gap, 13%filled
ARV drug prescriptions intermittently (ie, the “sometimes”
people), which may also put them at risk of viral rebound.
However, 44%of persons within our study had a gap that
lasted for 1 month; some of these individuals may have had
extra medication from a previous prescription that could be
used to cover the gap.
Failure to fill ARV drug prescriptions can be detected at
multiple steps before the prescribing provider is aware of the
situation, including by the filling pharmacies, insurers, and
pharmacy benefit managers. Using pharmacy filling data to
identify persons who fail to fill prescriptions and then to
intervene has been demonstrated with other chronic dis-
eases. For example, a study conducted by Lawrence et al
used pharmacy claims data to identify persons who were
60 days late filling prescriptions for a variety of cardiovas-
cular and diabetes medications. Identified persons received
a telephone intervention by care managers who counseled
patients on medication adherence. They found improved
rates of medication reinitiation (59%versus 42%in the
control group) and a shorter time to reinitiation (59 versus
107 days) postintervention.
39
Another study used prescrip-
tion fill data to determine persons who never filled an initial
prescription and followed up these individuals with tele-
phone reminders to fill their prescriptions. Persons who
received the intervention had improved primary adherence
(risk ratio 1.6, 95%CI 1.5-1.8) compared to the control
group.
40
Real-time monitoring of pharmacy claims data
could be used to intervene upon people who are no longer
filling their ARV drug prescriptions and to offer adherence
and other support.
41
This study is not without limitations. We restricted the
analysis to the first gap in care; filling behavior may have
changed during subsequent gaps. However, the median
number of gaps for persons included in the study was 1.
No HIV viral load data were available and, therefore, we
were unable to determine whether failing to fill ARV drug
prescriptions led to poor viral suppression. It is possible that
persons filled ARV drug prescriptions using a second
insurer (eg, spousal insurance benefit), which would not
be accounted for in this analysis. We were unable to deter-
mine whether persons had active prescriptions for ARV
drugs during the gap and, therefore, were unable to deter-
mine whether failure to fill was due to an access issue.
Finally, all persons within the sample were privately
insured; the results, therefore, may not be generalizable to
all persons with HIV, particularly to uninsured persons or to
persons who use alternative avenues to fill prescriptions
such as drug assistance programs.
The majority of persons who experienced a gap in HIV care
failed to fill an ARV drug prescription during the gap. The
failure to fill ARV drug prescriptions during a gap in care
emphasizes the importance of retention in HIV care, where
patients can receive adherence support and the importance of
treatment can be emphasized.
Authors’ Note
The findings and conclusions in this study are those of the authors and
do not necessarily represent the views of the Centers for Disease
Control and Prevention.
Declaration of Conflicting Interests
The author(s) declared no potential conflicts of interest with respect to
the research, authorship, and/or publication of this article.
Table 4. Factors Associated with Increased Odds of Never versus
Ever Filling 1 ARV Drug Prescription during a First Gap in Care.
a,b
Characteristic
n, (total
N¼14 308)
Univariate Multivariable
c
Odds ratio
(95% CI)
Odds ratio
(95% CI)
Age, years
18-29 1978 Referent 1.56 (1.39-1.74)
30-39 2871 1.03 (0.94-1.13)
40-49 5368 0.76 (0.71-0.82)
50 4091 1.01 (0.94-1.10)
Sex
Male 11 224 Referent
Female 3084 1.80 (1.64-1.98) 1.67 (1.52-1.83)
Region
Northeast 3488 Referent 1.86 (1.69-2.03)
North Central 2076 0.91 (0.83-1.01)
South 5785 0.79 (0.73-0.85)
West 2959 0.76 (0.69-0.82)
Abbreviations: ARV, antiretroviral; CI, confidence interval.
a
N¼14 308.
b
The outcome of the logistic regression analyses was “never” filling an ARV
drug prescription versus filling an ARV “sometimes” or “always.”
c
Multivariable logistic regression analysis comparing 18-29 years to persons
30 years, females to males and persons residing in the Northeast region to all
other regions combined.
636 Journal of the International Association of Providers of AIDS Care 16(6)
Funding
The author(s) disclosed receipt of the following financial support for
the research, authorship, and/or publication of this article: This study
was conducted as part of the authors’ normal work activities at the
Centers for Disease Control and Prevention. No outside funding was
used to conduct the study.
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