title: Prediction of progression to severe disease in women with late preterm hypertensive disorders of pregnancy.
abstract: BACKGROUND
  If hypertensive disorders of pregnancy are diagnosed before term, the benefits of immediate delivery need to be weighed against the neonatal consequences of preterm delivery. If we are able to predict which women are at high risk of progression to severe disease, they could be targeted for delivery and maternal complications might be reduced. In addition, this may prevent unnecessary preterm births in women at low risk.
  
  
  METHODS
  We developed a prediction model using data from the HYPITAT-II trail, which evaluated immediate delivery vs. expectant monitoring in women with non-severe hypertensive disorders of pregnancy between 34 and 37 weeks of gestation. Univariate and multivariate logistic regression analysis were used to identify relevant variables from clinical and laboratory parameters. The performance of the resulting prediction model was assessed by receiver operating characteristic analysis, calibration and bootstrapping, using the average predicted probabilities.
  
  
  RESULTS
  We included 519 women, 115 (22.2%) of whom developed severe hypertensive disorders of pregnancy. The prediction model included: maternal age (odds ratio 0.92 per year), gestational age (odds ratio 0.87 per week), systolic blood pressure (odds ratio 1.05 per mmHg), the presence of chronic hypertension (odds ratio 2.4), platelet count (odds ratio 0.996), creatinine (odds ratio 1.02) and lactate dehydrogenase (odds ratio 1.003). The model showed good fit (p = 0.64), fair discrimination (area under the curve 0.76, 95% confidence interval 0.73-0.81, p < 0.001) and could stratify women in three risk groups of average, intermediate and high risk (predicted probabilities <0.22, <0.44 and >0.45, respectively).
  
  
  CONCLUSIONS
  In women with non-severe hypertension in pregnancy near term, progression to severe disease can be predicted. This model requires external validation before it can be applied in practice.
authors: Department of Obstetrics and Gynecology, University of Groningen, University Medical Center Groningen, Groningen, The Netherlands.
authors: Eva F
authors: EF
authors: Zwertbroek
authors: Department of Obstetrics and Gynecology, University of Groningen, University Medical Center Groningen, Groningen, The Netherlands.
authors: Kim
authors: http://orcid.org/0000-0002-0441-7108
authors: K
authors: Broekhuijsen
authors: Department of Obstetrics and Gynecology, Atrium Medical Center Parkstad, Heerlen, The Netherlands.
authors: Josje
authors: http://orcid.org/0000-0003-0107-2332
authors: J
authors: Langenveld
authors: Department of Obstetrics and Gynecology, Academic Medical Center, Amsterdam, The Netherlands.
authors: Gert-Jan
authors: GJ
authors: van Baaren
authors: Department of Obstetrics and Gynecology, University of Groningen, University Medical Center Groningen, Groningen, The Netherlands.
authors: Paul P
authors: http://orcid.org/0000-0003-2241-3001
authors: PP
authors: van den Berg
authors: Department of Obstetrics and Gynecology, Reinier de Graaf Gasthuis, Delft, The Netherlands.
authors: Henk A
authors: HA
authors: Bremer
authors: Department of Obstetrics and Gynecology, Academic Medical Center, Amsterdam, The Netherlands.
authors: Wessel
authors: http://orcid.org/0000-0002-7243-2115
authors: W
authors: Ganzevoort
authors: Department of Obstetrics and Gynecology, Martini Hospital, Groningen, The Netherlands.
authors: Aren J
authors: AJ
authors: van Loon
authors: The Robinson Research Institute, School of Pediatrics and Reproductive Health, University of Adelaide, Adelaide, SA, Australia.
authors: Ben W J
authors: http://orcid.org/0000-0001-8337-550X
authors: BW
authors: Mol
authors: Department of Obstetrics and Gynecology, Onze Lieve Vrouwe Gasthuis, Amsterdam, The Netherlands.
authors: Maria G
authors: http://orcid.org/0000-0002-3020-8908
authors: MG
authors: van Pampus
authors: Department of Obstetrics and Gynecology, Medical Center Leeuwarden, Leeuwarden, The Netherlands.
authors: Denise A M
authors: DA
authors: Perquin
authors: Department of Obstetrics and Gynecology, Jeroen Bosch Hospital, 's-Hertogenbosch, The Netherlands.
authors: Robbert J P
authors: RJ
authors: Rijnders
authors: Department of Obstetrics and Gynecology, Grow, School for Oncology and Developmental Biology, Maastricht University Medical Center, Maastricht, The Netherlands.
authors: Hubertina C J
authors: HC
authors: Scheepers
authors: Department of Obstetrics and Gynecology, ZGT Almelo, Amelo, The Netherlands.
authors: Marko J
authors: MJ
authors: Sikkema
authors: Department of Obstetrics and Gynecology, Radboud University Medical Center, Nijmegen, The Netherlands.
authors: Mallory D
authors: MD
authors: Woiski
authors: Department of Epidemiology-HPC FA40, University of Groningen, University Medical Center Groningen, Groningen, The Netherlands.
authors: Henk
authors: H
authors: Groen
authors: Department of Obstetrics and Gynecology, University of Groningen, University Medical Center Groningen, Groningen, The Netherlands.
authors: Maureen T M
authors: http://orcid.org/0000-0001-6887-0262
authors: MT
authors: Franssen
mesh_terms: D000328:Adult; D001794:Blood Pressure; D003404:Creatinine / Q000032:analysis; D018450:Disease Progression; D005260:Female; D005865:Gestational Age; D006801:Humans; D046110:Hypertension, Pregnancy-Induced / Q000453:epidemiology*; D007770:L-Lactate Dehydrogenase / Q000032:analysis; D008423:Maternal Age; D015233:Models, Statistical; D015999:Multivariate Analysis; D009426:Netherlands / Q000453:epidemiology; D010976:Platelet Count; D011247:Pregnancy; D011507:Proteinuria / Q000453:epidemiology; D016032:Randomized Controlled Trials as Topic; D018570:Risk Assessment; D055815:Young Adult
chemical_list: D003404:Creatinine; D007770:L-Lactate Dehydrogenase
keywords: Clinical prediction model; chronic hypertension; gestational hypertension; high-risk pregnancy; preeclampsia