18 - Blood Pressure Control in Patients with Chronic Hypertension and Diabetes: Should <130/80 be the target?

The Chronic Hypertension and Adverse Pregnancy Study (CHAP) demonstrated that a target blood pressure of < 140/90mm Hg during pregnancy is associated with improved perinatal outcomes. Patients with pregestational diabetes may benefit from even tighter control with a target blood pressure (BP) < 130/80 mm Hg. We aimed to compare perinatal outcomes in patients with hypertension and diabetes who achieve BP < 130/80 versus 130-139/80-89.

Study Design:

Secondary analysis of the CHAP study, a multi-center randomized controlled trial. Participants were included in this secondary analysis if they had pregestational diabetes or gestational diabetes (GDM) diagnosed < 20 weeks and at least three BP measurements prior to delivery. Average systolic and diastolic BP were calculated using the baseline BP and prenatal clinic BPs. The primary composite outcome was preeclampsia with severe features, indicated preterm birth < 35 weeks, or placental abruption. Secondary outcomes were components of the primary outcome, fetal or neonatal death, and small for gestational age (SGA). Comparisons were made between those with an average systolic BP < 130 and average diastolic BP < 80 to those with an average blood pressure 130-139/81-89 using Student’s t-test and chi-squared tests. Multivariable log-binomial regression models accounted for differences between groups.

Results:

Of 434 participants included, 217 had an average BP < 130/80 and 217 had an average BP 130-139/80-89. Participants with an average BP < 130/80 were more likely to have newly diagnosed chronic hypertension, be on medications at the start of pregnancy and more likely to have newly diagnosed GDM. Participants with an average BP 130-139/80-89 were more likely to have the primary adverse perinatal outcome (51.6% vs 22.6%, adjusted relative risk (aRR) 2.31, p< 0.01) without a decrease in the risk of SGA (9.2% vs 5.1%, aRR 1.87, p=0.08) or fetal or neonatal death (3.2% vs < 1%, aRR 3.91, p=0.08).

Conclusion:

Treating patients with DM and chronic hypertension to a goal blood pressure of < 130/80 may be associated with improved perinatal outcomes.