Smoking, HIV, and risk of pregnancy loss

Abstract

Objective:Cigarette smoking during pregnancy increases risks of poor pregnancy outcomes including miscarriage and stillbirth (pregnancy loss), but the effect of smoking on pregnancy loss among HIV-infected women has not been explored. Here, investigated the impact of smoking on risk of pregnancy loss among HIV-positive and HIV-negative women, and estimated the potential impact of realistic smoking cessation interventions on risk of pregnancy loss among HIV-positive women.Design:We analyzed pregnancy outcomes in HIV-positive and HIV-negative participants in the Women's Interagency HIV Study between 1994 and 2014.Methods:We estimated effects of current smoking at or immediately before pregnancy on pregnancy loss; we controlled for confounding using regression approaches, and estimated potential impact of realistic smoking cessation interventions using a semiparametric g-formula approach.Results:Analysis examined 1033 pregnancies among 659 women. The effect of smoking on pregnancy loss differed dramatically by HIV status: adjusted for confounding, the risk difference comparing current smokers to current nonsmokers was 19.2% (95% confidence limit 10.9–27.5%) in HIV-positive women and 9.7% (95% confidence limit 0.0–19.4%) in HIV-negative women. These results were robust to sensitivity analyses. We estimated that we would need to offer a realistic smoking cessation intervention to 36 women to prevent one pregnancy loss.Conclusion:Smoking is a highly prevalent exposure with important consequences for pregnancy in HIV-positive pregnant women in the United States, even in the presence of potent highly active antiretroviral therapy. This evidence supports greater efforts to promote smoking cessation interventions among HIV-positive women, especially those who desire to become pregnant.

Pregnancy Loss in Women With Hiv Is Not Associated With Hiv Markers: Data From a National Study in Italy, 2001-2018

“…We also found no effect of BMI, another potentially modifiable risk factor for pregnancy loss,10 also when the risk was assessed specifically for the presence of overweight and/or obesity (data not shown). Finally, we found no significant role of smoking, in discordance with the observations by Flenady et al in the general population10 and by Westreich et al in women with HIV 16. We also found no association of pregnancy loss with hypertension and parity, that represented risk factors in larger studies evaluating the general population 9,10.…”

Attributes of HIV infection over decades (1982–2018): A systematic review and meta‐analysis

“…HIV‐positive people who smoke are more likely to get HIV‐related infections such as thrush or pneumonia (Dharma N. Bhatta, Subedi, & Sharma, 2018; Rahmanian et al., 2011). Moreover, smoking causes an increase in the MTCT of HIV (Westreich et al., 2017). Likewise, alcohol is the most commonly abused substance in HIV patients and correlates with illicit drug use (Galvan et al., 2002).…”

A Review of Time Scale Fundamentals in the g-Formula and Insidious Selection Bias

“…[46]), pooled linear regression (e.g. [59] [30]), multi-state models (e.g. [14, 60]), multinomial regression (e.g.…”

“…The point exposure case has become a relatively common example of the g-formula (e.g. [10, 18, 28, 30–32, 34, 39, 43, 65–73]); likely because it is a straightforward extension to common modeling frameworks. We focus on the more general case of using the g-formula for survival analysis with time-varying exposure and confounders.…”

“…In other cases, landmark events such as HIV seroconversion [50], pregnancy [30, 31] or hospitalization [32] define the start of the time scale. In the case of seroconversion and pregnancy, the precise start of the time scale may be unknown, and current approaches to this problem with the g-formula involve imputing the start of the time scale (e.g.…”