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Excellent Adherence Shifts Medical Costs from Inpatient Care to Prescription ART Costs
Edward Gardner*1,2, M Maravi1, W Burman1,2, C Rietmeijer1,2, and A Davidson1,2
1Denver Publ Hlth, CO, US and 2Univ of Colorado Hlth Sci Ctr, Denver, US
Background: Adherence to potent ART is associated with
improved health outcomes. Cost models suggest that excellent adherence would be
cost saving, but this has not been assessed with patent data.
Methods: Retrospective analysis of treatment-naïve
patients starting ART (≥3 antiretroviral medications), 1997-2003, followed
for at least 6 months. Adherence was calculated using pharmacy refill data for
the initial 6 months of therapy. Medical charges, obtained from administrative
databases, were adjusted to 2005 US$. Average wholesale price (2005)
was used for ART.
Results: We included 310 patients starting ART. The
cohort was mostly men (89%), median age 37 years, and most were men who have
sex with other men (64%). Median baseline CD4 count and HIV-1 viral load were 168
cells/mL
(interquartile range [IQR] 54 to 286) and 5.0 log
copies/mL (IQR 4.5 to 5.6), respectively. We divided
the cohort into adherence quartiles and evaluated annualized costs. In a
multivariate logistic regression model, lower baseline CD4 count (OR 1.30,
95%CI 1.12 to 1.49, per 100 cell decrease, p
<0.001) and higher adherence (OR 1.21, 95%CI 1.09 –to 1.34, per 10%
increase, p <0.001) were
significantly associated with annualized total medical costs above the median.
Patients in the lowest adherence quartile, compared to the upper 3 quartiles,
were more likely to have at least 1 inpatient stay (53% vs
32%, p <0.001) and at least one1
emergency room visit (53% vs 39%, p = 0.03).
Adherence
Quartile
|
Median
Adherence %
(IQR)
|
Mean
Years of Follow-up
|
Median
Baseline CD4
Count (IQR)
|
Mean Total Medical Cost
|
Mean
Inpatient
Cost
|
Mean Outpatient Cost
|
Mean ART Cost
|
First
|
100 (100-100)
|
3.4
|
215 (45-387)
|
$25,185
|
$1,824
|
$6,265
|
$17,096
|
|
Second
|
97.4 (96.2-98.4)
|
3.7
|
179 (63-321)
|
$26,221
|
$3,861
|
$6,604
|
$15,756
|
|
Third
|
86.1 (82.0-91.3)
|
3.0
|
137 (31-250)
|
$24,608
|
$3,010
|
$7,501
|
$14,096
|
|
Fourth
|
47.3 (20.2-65.6)
|
3.1
|
156 (72-343)
|
$21,548
|
$5,163
|
$7,772
|
$8,613
|
|
p value
|
N/A
|
0.15
|
0.15
|
<0.001
|
<0.001
|
0.26
|
<0.001
|
Conclusions: Excellent ART adherence shifted, but did not
decrease healthcare costs in a cohort of previously ART-naïve patients. Of
medical costs evaluated, drug costs may be the most fluid; thus, lower drug
costs and excellent adherence could decrease total healthcare costs. Other
potential cost advantages (productivity, quality of life, etc.) associated with
excellent adherence should be evaluated in future studies.
|
