METHODS: Hospital discharge data were examined for Wisconsin resident women delivering in a Wisconsin facility. ICD-9-CM diagnosis and procedure codes were used to identify delivery hospitalizations with a documented hypertensive disorder using methods described by Kuklina et al. (2009). Discrete categories examined included eclampsia/severe preeclampsia, mild preeclampsia, chronic hypertension, and gestational hypertension. Trends were examined for 2005-2014 and rates were age-adjusted to the 2005 distribution of births by maternal age. Postpartum hospitalizations, within six months of delivery, for women who had a hypertensive disorder at delivery (2010-2013) were identified using a file of linked hospitalizations to the same person over time (2010-2014).
RESULTS: The age-adjusted prevalence of any hypertensive disorder among delivery hospitalizations increased from 82.8/1,000 deliveries in 2005 to 99.4/1,000 deliveries in 2014 (p for trend <0.05). Each category of hypertensive disorders increased significantly over the time period examined except for mild preeclampsia which decreased. Eclampsia/severe preeclampsia had the largest relative increase over the time period at 61%. Among all women with a hypertensive disorder at delivery during 2010-2013 (N=22,692), 3.4% were hospitalized within the 6 months after delivery. The principal diagnosis for these postpartum hospitalizations was most often related to pregnancy/birth complications (56.6%), followed by hypertension (14.1%), digestive conditions (5.9%), and mental health or substance use (5.4%).
CONCLUSIONS: The prevalence of hypertensive disorders at delivery is increasing in Wisconsin. Although only a small proportion of women who were hypertensive at delivery are rehospitalized, those subsequent hospitalizations are often related to hypertension or other complications from pregnancy and childbirth. This presents an opportunity to examine quality of care and management at the time of delivery for women with hypertensive disorders in order to prevent postpartum hospitalizations. These findings will inform activities by the Wisconsin Perinatal Quality Collaborative (WisPQC) which has selected hypertensive disorders for its inaugural quality improvement project. Next steps include examining multiple postpartum hospitalizations and whether women with hypertensive disorders are readmitted to the hospital where they delivered.