Clinical Influence of Nonadherence With Prophylactic #Aspirin in Preventing #Preeclampsia in High-Risk Pregnancies

..Women with inadequate adherence had higher incidence of early-onset preeclampsia (17% versus 2%; odds ratio [OR], 1.9 [95% CI, 1.1–8.7]; P=0.04), late-onset preeclampsia (41% versus 5%; OR, 4.2 [95% CI, 1.4–19.8]; P=0.04), intrauterine growth restriction (29% versus 5%; OR, 5.8; [95% CI, 1.2–8.3]; P=0.001), preterm delivery (27% versus 10%; OR, 5.2 [95% CI, 1.5–8.7]; P=0.008), and higher likelihood of increase in antihypertensives antenatally (60% versus 10%; OR, 4.6 [95% CI, 1.2–10.5]; P=0.003).

Kaplan-Meier analysis demonstrated lower incidence of premature delivery in the ≥90% adherent group (HR, 0.3 [95% CI, 0.2–0.5]; P<0.001).Kappa coefficient agreement between qualitative and quantitative assessment of adherence was moderate (κ=0.48; SE=0.029; P<0.0001).

Our data demonstrates that aspirin is an effective prophylactic agent with an absolute risk reduction of 51% (number needed to treat, 2) when adherence is ≥90%, compared with women with inadequate adherence. Women who were <90% adherent had higher rates of preeclampsia, intrauterine growth restriction, preterm delivery, and increase in antenatal antihypertensive requirements. Self-reported adherence does not accurately reflect actual adherence