Bilirubin levels in infants following in utero atazanavir exposure compared to exposure to other antiretrovirals

Chee and colleagues showed results from a small retrospective cohort study looking at infant billirubin levels in infants of mothers enrolled from a pregnancy registry at Inova Fairfax Hospital, Richmond, Virginia.

The primary outcome in this study was mean billirubin level within 72 hours after birth among three groups: atazanavir (ATV), another PI or NNRTI exposure. The secondary outcome was the proportion of infants with billirubin levels greater than 5mg/dL within 24 hours and reported clinical jaundice.

The investigators reported that, out of 52 infants born between 1999 to 2009 to mothers receiving ATV (n=12), another PI (n=21) or a NNRTI (n=19), 22 had billirubin levels measured to secondary to jaundice risk factors or clinical jaundice.

They found mean billirubin levels of: 6.7mg/dL (95% CI, 4.9-8.5), 5.5mg/dL (95% CI, 2.9-8.1) and 4.8 mg/dL (95% CI, 0-11.2, p=0.36), in the ATV, other PI and NNRTI groups respectively. Among the 16 infants with levels measured within 24 hours 7/8 (88%), 3/6 (50%) and 0/2 had concentrations greater than 5mg/dL, in the same groups respectively, p=0.03.

They noted that all preterm infants <37 weeks infants or those with a history of jaundiced sibling had billirubin greater than 5mg/dL at 24 hours. Clinical jaundice was recorded in 3/12 (25%), 4/21 (19%) and 1/19 (5%) in the ATZ, other PI and NNRTI respectively.

They concluded that at 72 hours billirubin levels were not significantly different among the three groups but the difference at 24 hours in the proportion of infants with concentrations greater than 5mg/dL was significant. They suggested that, although ATV exposed infants could be at increased risk for elevated billirubin levels, these levels may not lead to clinically significant jaundice.

Ref: Chee JE et al. Comparison of neonatal bilirubin levels following in utero exposure to atazanavir versus exposure to other antiretroviral agents. 50th ICAAC Boston, 12-15 September 2010. Poster abstract H1664.