520
Adherence Levels, Virological Responses, and Immunological Outcomes among Patients Initiating cART in the VA Healthcare System
Scott Braithwaite*1, M Kozal1, C Chang2, M Roberts2, S Fultz1, M Goetz3, C Gibert4, M Rodriguez-Barradas5, L Mole6, and A Justice1
1Yale Univ, New Haven, CT, US; 2Univ of Pittsburgh, PA, US; 3Univ of California, Los Angeles, US; 4George Washington Univ Med Ctr, Washington, DC, US; 5Baylor Coll of Med, Houston, TX, US; and 6VA Ctr for Quality Mgmt in Publ Hlth, Palo Alto, CA, US
Background: Few data directly compare the effectiveness of
boosted-protease inhibitor (b-PI) regimens and efavirenz (EFV) -based regimens in
ART-naïve populations in routine clinical care.
Methods: We synthesized administrative, laboratory,
and pharmacy data from the VA Healthcare System to compare the outcomes of patients
starting combination ART (cART). We limited analyses to patients unlikely to
have prior ART exposure, and varied the identification algorithm in sensitivity
analyses. Regimens were divided into EFV, nevirapine (NVP), b-PI, and
non-boosted PI (s-PI) -based categories. b-PI were further divided into newer
(lopinavir, fosamprenavir, or atazanavir) and older (including none of these
drugs) subgroups. Outcome measures were adherence, viral load suppression at 1
year, and changes in log viral load and CD4 counts at 1 year. Adherence was
estimated from pharmacy refill records using previously validated algorithms.
Multivariate models were used to adjust for covariates and propensity scoring
was used to adjust for confounding by treatment assignment.
Results: In the VA system between 1997 and 2004, 6394 individuals
with little likelihood of prior ART exposure started cART. While adherence
overall was poor (63% of doses taken as prescribed), adherence with EFV (67%)
and NVP (65%) regimens was significantly greater than adherence with b-PI (59%)
or s-PI (61%) regimens (p <0.001).
EFV regimens were more likely to suppress viral load at 1 year (81%) than were
NVP (72%), b-PI (70%), or s-PI (65%) regimens (all p <0.001). In multivariate analyses, viral load suppression was inferior
for NVP (OR 0.60), b-PI (OR 0.57), and s-PI (OR 0.48) regimens compared to EFV (all
p <0.001). When b-PI were divided into
newer and older groups, EFV suppressed viral load more effectively than older
b-PI, but its superiority to newer b-PI was less robust, varying with covariate
and propensity score assumptions. Overall, EFV also yielded more favorable
immunological outcomes than other regimens (CD4 increase, 18 to 31 cells/mm3
higher; p <0.05).
Conclusions: In this VA cohort of >6000 HIV+
individuals initiating their first cART, EFV-based regimens had improved
virologic and immunologic outcomes and higher adherence levels than those
starting s-PI- or b-PI-based regimens.
|
