Committee for Academic Affairs JSSHP Research Award 2019 Clinical Research Hyperbaric area index, a novel method to predict outcome of patients with hypertension disorder pregnancy

Introduction: The aim of the study was to evaluate if hyperbaric area index (HBI) can be a good predictor for adverse neonatal outcome in patients with hypertensive disorder pregnancy. Method: A retrospective study enrolled 78 cases whose 24 hours ambulatory blood pressure monitoring (ABPM) was measured before delivery was performed. Patients were divided into two groups by the timing of measurement after 20 gestational weeks or not. HBI scores that obtained by integral calculator of the difference between the measured blood pressure and base line to time axis were calculated. Neonatal outcomes including gestational week at birth and infant weight were evaluated. The ROC curve was used to determine the association between scores and neonatal outcomes. Result: Of 78 women, 33 were measured less than 20 weeks and 45 were measure after 20 weeks. The mean gestational weeks at delivery was 36 ± 2.2 weeks, and the mean birth weight was 2,540 ± 590 g. When the blood pressure baseline was set as 140 mmHg, the cutoff value of the score is 43.5 mmHg-hour (AUC is 0.741), and the odds ratio of birth weight < 2,000 g is 8.3 (95%CI: 2.7–28.0). However, the AUCs were 0.778 in the group after 20 weeks and 0.345 in the group less than 20 weeks respectively. When the blood pressure criteria value was set to 135 mmHg, the AUC in the group less than 20 weeks increased to 0.707. Conclusion: HBI can be a useful predictor for adverse neonatal outcome in patients with hypertensive disorder pregnancy.