Factors Associated with Refractory Severe Hypertension in Patients with Preeclampsia.

Objective:  This study aimed to identify factors associated with refractory severe hypertension that does not resolve after an initial dose of antihypertensive medication in patients with preeclampsia.

Study design:  This was a retrospective study of all pregnant and postpartum individuals with a diagnosis of preeclampsia, superimposed preeclampsia, HELLP (hemolysis, elevated liver enzymes, low platelet) syndrome, or eclampsia who delivered at 22 weeks or greater at a single academic institution from 2010 to 2020. Inclusion criteria were patients with preeclampsia who developed severe hypertension (systolic pressure ≥160 mm Hg or diastolic pressure ≥110 mm Hg) and received antihypertensive medications for acute severe hypertension. We defined refractory severe hypertension as a systolic blood pressure of ≥160 mm Hg or a diastolic blood pressure of ≥110 mm Hg that did not improve after receiving the initial treatment. To evaluate for factors associated with refractory severe hypertension, we developed multivariable modified Poisson regression using all variables with p-value <0.1 on bivariable analysis and calculated adjusted relative risks (aRRs) with 95% confidence intervals (95% CIs).

Results:  Of 850, 386 (45.4%) had refractory severe hypertension and 464 (54.6%) responded to the initial antihypertensive medications. Factors associated with refractory severe hypertension included higher body mass index (BMI), chronic hypertension, and higher systolic pressure. Every 5 kg/m² increase in BMI was associated with a 7% increased risk of refractory severe hypertension (aRR = 1.07; 95% CI: 1.02-1.12). Every 10 mm Hg increase in systolic blood pressure was associated with a 10% increased risk of refractory severe hypertension (aRR = 1.10; 95% CI: 1.04-1.17). Chronic hypertension was associated with a 25% increased risk of refractory severe hypertension (aRR = 1.25; 95% CI: 1.01-1.56) in the diastolic pressure model.

Conclusion:  Refractory severe hypertension was associated with elevated BMI, chronic hypertension, and higher systolic blood pressure.

Key points: · Risk factors for refractory severe hypertension are not well-known.. · Almost half of the patients had refractory severe hypertension.. · Higher BMI, chronic hypertension, and higher systolic pressure were the risk factors.. · These patients would require closer follow-up and prompt response to vital signs..