Background:  Use of abacavir (ABC) has been associated with increases in cardiovascular disease and markers of inflammation. Further evaluation of ABC use and inflammation is needed.

Methods:  We identified Multicenter AIDS Cohort Study (MACS) men and Womens’ Interagency HIV Study (WIHS) women who initiated ABC either at or after first HAART initiation while under follow-up. Propensity score methods were used to identify ABC-unexposed person-visits matched by race/ethnicity, age, calendar time, smoking, body mass index, HDL, HCV serostatus, pre-HAART ART use, duration and consistency of HAART use, CD4, and HIV RNA levels. High-sensitivity C-reactive protein (hsCRP), interleukin-6 (IL-6), and D-dimer levels were measured at the pre-HAART visit (baseline) and at the on-HAART index visit defined as the first visit  at which ABC use was reported (exposed) or a matched visit without ABC use (unexposed). Since visits were semi-annual, onset of ABC use could be <1 to 6 months before the study visit. Random-effects models were used to compare log-transformed markers and changes from pre-HAART levels in ABC and non-ABC initiators.

Results:  We measured hsCRP and D-dimer levels in 326 matched pairs (197 women; 129 men) and IL-6  levels in 290 matched pairs (194 women; 96 men). In unadjusted models, ABC users at the index visit had 7% lower mean D-dimer levels (0.26 vs 0.28 mg/mL, p = 0.40), 8% higher hsCRP (1.69 vs 1.56 mg/mL, p = 0.41), and 1% higher IL-6 (2.20 vs 2.17 pg/mL, p = 0.90) than non-ABC users. In multivariate models, differences at index visit between ABC exposed and unexposed were:  –3% for D-dimer (p = 0.66), +2% for hsCRP (p = 0.80), and –5% for IL-6 (p = 0.58). In this model women had lower mean D-dimer levels (–5% difference, p = 0.70), significantly lower hsCRP levels (–33%, p = 0.01), and significantly lower IL-6 levels (­–38%, p = 0.001) than men. Comparisons of baseline and index visits (mean 4.2 years apart) revealed decreases in D-dimer (p <0.001) and IL-6 (p = 0.08) and increases in hsCRP levels (p <0.001). However, the changes in markers between visits were not significantly different when comparing ABC exposed and unexposed persons (D-dimer p = 0.82, hsCRP p = 0.64, and IL-6 p = 0.47).

Conclusions:  ABC use was not independently associated with elevated plasma levels of hsCRP, IL-6, and D-dimer. While changes in the levels of these markers were seen between the baseline and index visits (D-dimer and IL-6 decreases, hsCRP increases), they were comparable among persons who initiated ABC versus non-ABC containing HAART. Women had higher D-dimer and lower CRP levels than men.