The contribution of birth defects to preterm birth and low birth weight.

OBJECTIVE: To assess the impact of birth defects on preterm birth and low birth weight. METHODS: Data from a large, prospective multi-center trial, the First and Second Trimester Evaluation of Risk (FASTER) Trial, were examined. All live births at more than 24 weeks of gestation with data on outcome and confounders were divided into two comparison groups: 1) those with a chromosomal or structural abnormality (birth defect) and 2) those with no abnormality detected in chromosomes or anatomy. Propensity scores were used to balance the groups, account for confounding, and reduce the bias of a large number of potential confounding factors in the assessment of the impact of a birth defect on outcome. Multiple logistic regression analysis was applied. RESULTS: A singleton liveborn infant with a birth defect was 2.7 times more likely to be delivered preterm before 37 weeks of gestation (95% confidence interval [CI] 2.3-3.2), 7.0 times more likely to be delivered preterm before 34 weeks (95% CI 5.5-8.9), and 11.5 times more likely to be delivered very preterm before 32 weeks (95% CI 8.7-15.2). A singleton liveborn with a birth defect was 3.6 times more likely to have low birth weight at less than 2,500 g (95% CI 3.0-4.3) and 11.3 times more likely to be very low birth weight at less than 1,500 g (95% CI 8.5-15.1). CONCLUSION: Birth defects are associated with preterm birth and low birth weight after controlling for multiple confounding factors, including shared risk factors and pregnancy complications, using propensity scoring adjustment in multivariable regression analysis. The independent effects of risk factors on perinatal outcomes such as preterm birth and low birth weight, usually complicated by numerous confounding factors, may benefit from the application of this methodology, which can be used to minimize bias and account for confounding. Furthermore, this suggests that clinical and public health interventions aimed at preventing birth defects may have added benefits in preventing preterm birth and low birth weight. LEVEL OF EVIDENCE: II.

Health literacy, antiretroviral adherence, and HIV-RNA suppression: a longitudinal perspective.

BACKGROUND: Low health literacy has been associated with worse adherence to antiretroviral therapy (ART) and higher HIV-RNA levels, but these relationships have not been evaluated in longitudinal analyses. METHODS: We evaluated literacy using the Rapid Estimate of Adult Literacy in Medicine (REALM) (< or = 6th grade, 7th to 8th grade, > or = 9th grade) in the HIV-Alcohol Longitudinal Cohort study of HIV-infected persons with a history of alcohol problems, conducted from 1997 to 2001. We tested HIV-RNA levels and administered a standardized questionnaire regarding demographics, substance use, receipt of ART, and adherence with ART, every 6 months for up to 7 occasions. Among the 235 subjects on ART, we investigated the relationship between literacy and 2 outcomes: 100% 3-day self-reported adherence and HIV-RNA suppression (<500 copies). RESULTS: Subjects' literacy levels were the following: 14% < or = 6th grade, 29% 7th to 8th grade, and 57% > or = 9th grade. In 66% of the observations (478/725), subjects reported 100% 3-day adherence with ART. Of the 685 HIV-RNA assays from these subjects, 62% had <500 copies. In unadjusted analyses, subjects with the lowest literacy level (< or = 6th grade) had a higher odds of adherence (odds ratio [OR] 2.23, 95% confidence interval 1.15 to 4.30) and HIV-RNA suppression (OR 2.01, 95% confidence interval 1.03 to 3.90) compared with those with > or = 9th grade literacy. This trend persisted but was no longer statistically significant in adjusted models of adherence (AOR 1.93, 95% confidence interval 0.86 to 4.31) and HIV-RNA suppression (AOR 1.70, 95% confidence interval 0.79 to 3.65). CONCLUSION: Contrary to our hypothesis, low literacy was not associated with a lower odds of adherence or virologic suppression in this longitudinal analysis of HIV-infected patients with a history of alcohol problems. Indeed, trends in these data suggest the possibility that low literacy may be associated with a higher odds of adherence and virologic suppression. These counterintuitive findings underscore the need to pursue a fuller understanding of the mechanisms by which literacy affects health outcomes.