The predicted risk of adverse pregnancy outcomes as a result of treatment-associated obesity in a hypothetical population receiving TAF/FTC/DTG, TDF/FTC/DTG or TDF/FTC/EFV.

Objective Integrase inhibitors, including dolutegravir (DTG), are associated with weight gain and obesity, especially when combined with tenofovir alafenamide (TAF). Obesity increases the risk of adverse pregnancy outcomes (APOs). This study aimed to predict the risk of APOs caused by treatment-associated obesity, using a hypothetical sample based on the ADVANCE trial. Design Risk prediction. Methods Firstly, a meta-analysis was performed to determine the relative risk (RR) for APOs in women with obese (≥30) versus normal prepregnancy BMIs (18.5-24.9). For the hypothetical sample, 3000 nonpregnant women with normal BMIs at Week 0 of treatment were evenly allocated across the following treatment arms: TAF/FTC+DTG, TDF/FTC+DTG, TDF/FTC/EFV. The treatment-associated obesity rates from ADVANCE were used to calculate the number of women with obese and normal BMIs expected at Week 96 in our sample. This was combined with the APO RRs to predict the number of women at risk of APOs, in each treatment arm, assuming they conceived at Week 96. Results At Week 96, the percentage of women predicted to be obese was 14.1% with TAF/FTC+DTG, 7.9% with TDF/FTC+DTG and 1.5% with TDF/FTC/EFV. The RR in women with obese versus normal BMIs was significantly higher for most APOs. Therefore, the number of women at risk of APOs was higher with TAF/FTC+DTG than TDF/FTC+DTG and TDF/FTC/EFV. For example, 11/1000 additional gestational hypertension cases were predicted with TAF/FTC+DTG, 6/1000 with TDF/FTC+DTG and 1/1000 with TDF/FTC/EFV. Conclusion Treatment-associated obesity increased the APO risk in women. This risk is likely to increase, as preliminary data from ADVANCE demonstrates ongoing weight gain beyond Week 96.