HIV-positive Brazilian women find adherence hard

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The majority of HIV-positive Brazilian women do not adhere properly to their HAART regimens, however, if a woman is pregnant her adherence is better, according to a poster presentation to the 43rd ICAAC in Chicago on September 15th.

The finding that Brazilian women have low levels of adherence is in stark contrast to Brazilian adherence studies presented to the International AIDS Society conference in Paris in July, which suggested that HAART-treated Brazilians usually achieve very high levels of adherence to anti-HIV therapy.

A prospective cohort of 72 HIV-positive pregnant women and 79 HIV-positive women who were not pregnant and receiving care at a public HIV clinic at a university in San Paulo were included in the study. Adherence was assessed monthly using a pill count and a structured questionnaire which asked about pill taking in the previous four days. Women were assessed as adherent if they took at least 95% of their doses correctly.

Glossary

odds ratio (OR)

Comparing one group with another, expresses differences in the odds of something happening. An odds ratio above 1 means something is more likely to happen in the group of interest; an odds ratio below 1 means it is less likely to happen. Similar to ‘relative risk’. 

prospective study

A type of longitudinal study in which people join the study and information is then collected on them for several weeks, months or years. 

p-value

The result of a statistical test which tells us whether the results of a study are likely to be due to chance and would not be confirmed if the study was repeated. All p-values are between 0 and 1; the most reliable studies have p-values very close to 0. A p-value of 0.001 means that there is a 1 in 1000 probability that the results are due to chance and do not reflect a real difference. A p-value of 0.05 means there is a 1 in 20 probability that the results are due to chance. When a p-value is 0.05 or below, the result is considered to be ‘statistically significant’. Confidence intervals give similar information to p-values but are easier to interpret. 

pill burden

The number of tablets, capsules, or other dosage forms that a person takes on a regular basis. A high pill burden can make it difficult to adhere to an HIV treatment regimen.

There were no social or educational differences between the pregnant and non-pregnant women. The pregnant women, however, tended to be younger (mean age 29 years versus 39 years, p

The number of pills which the pregnant women were being asked to take was significantly higher than the number that non-pregnant women were taking, with 63.9% taking six or more pills a day compared to only 13.9% of their non-pregnant peers (p

According to the pill count, 43.1% of pregnant women achieved 95% adherence. This was significantly higher than non-pregnant women: only 17.7% of non-pregnant women managed to take at least 95% of their doses (p

The level of adherence to protease inhibitor-containing regimens was not significantly worse than adherence to those containing an NNRTI (p=0.74), despite the fact that protease inhibitors are associated with higher pill counts and more side-effects.

Factors independently associated with higher levels of adherence were being pregnant (odds ratio [OR] 2.5), being aged at least 29 years (OR = 3.5), and a pill burden of six or less a day (OR = 2.6).

The investigators concluded that optimum adherence to HAART was rare. Even though pregnant women achieved better levels of adherence than those who were not pregnant, the average level of adherence was still low, and at such a suboptimal level that effective antiretroviral prophylaxis to prevent mother-to-baby transmission of HIV could be compromised. It should, however, be pointed out that this conclusion is flawed as the investigators did not gather data on adherence to therapy at delivery and post-partum, which is key to preventing mother-to-baby transmission of HIV.

References

Vaz MJR et al. Adherence with antiretroviral therapy during pregnancy. 43rd ICAAC, abstract H-859, Chicago September 14 - 17th, 2003.