Bearing in mind the results of this study indicated that 182 (66.9%) postpartum patients with HDP did not adhere to BP monitoring at 1, 6, and 12 weeks after discharge, the univariate and multivariate analysis demonstrated that the education level of high school or below, parity, and delivery gestational age were identified as the significant independent factors for the occurrence of poor adherence to BP monitoring in postpartum patients with HDP within 3 months after the discharge from the hospital.
BP of the postpartum patients with HDP has been reported to decrease within 48 hours following delivery, but to increase to a peak 3–6 days postpartum at a time after hospital discharge [7, 21–22], and about 2–4% of their BP persists up to beyond 12 weeks postpartum [23]. Elevated BP is associated with severe morbidity [24]. The majority of cases of postpartum strokes and heart failure, which are often complications of hypertensive disease, occur within 10–11 days after discharge postpartum. In addition, eclamptic seizures postpartum can also occur and are often preceded by symptoms [25]. Moreover, according to a previous large survey study by Petersen and colleagues [9], more than 60% of deaths due to gestational hypertensive disease occur during the first 6 weeks postpartum. Therefore, short-interval visits to review BP logs and assess for signs or symptoms of a severe disease after discharge, so that providers can identify and address the disease before it occurs, are essential and practical.
The majority of management recommendations are, however, focused on antepartum BP goals and surveillance [2, 26], and recommendations for monitoring hypertension in the postpartum period have just started to emerge over the past decades [1–2, 17, 27–28]. In 2018, while the ACOG recommended monitoring BP at 72 h postpartum and 7–10 days postpartum [15], the Society for Maternal-Fetal Medicine also issued a special statement in 2021 emphasizing the importance of postpartum follow-up, recommending at least one time of BP monitoring at 7–10 days postpartum and that face-to-face follow-up or telemedicine follow-up should be scheduled within 3 weeks postpartum[29]. In the same year, the Chinese guidelines in 2021 recommend that postpartum females with HDP should have their BP monitored continuously for at least 6 weeks after being discharged. Moreover, these patients should measure BP, perform urine routine, and lipid and glucose screening 3 months postpartum [17]. What is more, it would appear that, based on existing literature, our study followed up the BP of postpartum HDP patients at 1, 6, and 12 weeks after discharge from the hospital is consistent with the requirement of postpartum BP monitoring and has clinical significance for the detection of postpartum hypertensive complications.
Our study is the first report of adherence to BP monitoring in postpartum patients with HDP for 3 months after discharge, which found that only 33.1% of the patients adhered to constant BP monitoring at 1, 6, and 12 weeks after discharge. While 84.6%, 75.7%, and 49.6% of the patients had their BP monitored at 1, 6, and 12 weeks after discharge, respectively. ACOG[7], Mogos MF[6], and Romagano[30] reported that the BP monitoring rate within 7–10 days postpartum was 30.0–51.1%, while 52.3–63.0% of the postpartum HDP patients attended a postpartum BP visit around 6 weeks postpartum[18, 31], and 24.0–49.0% attended a visit around 12 weeks postpartum[31–32]. All these previously reported BP monitoring rates were lower than those of our study, which tentatively demonstrates a positive effect of targeted discharge education in improving adherence to post-discharge BP monitoring in females with HDP.
Until now, only two studies studied the examined predictors of postpartum BP screening visit attendance within 7–10 days after delivery [30, 33], and various studies have identified predictors of 6–week postpartum visit attendance [18, 31–32, 34–41]. The non-Hispanic Black identity was associated with a lower likelihood of BP screening attendance within 7–10 days of delivery [30] and females with gestational hypertension, with inadequate and intermediate prenatal care utilization, and those delivered vaginally were less likely to attend postpartum BP screening compared to females with preeclampsia with severe features, with adequate prenatal care utilization, and who had cesarean deliveries within 10 days of delivery [33]. And it is widely recognized that postpartum visit attendance at 6 weeks is lowest among females who are non-Hispanic Black, of ethnic-minority groups, younger, multiparous, unmarried, low-income, have inadequate prenatal care use, publicly insured or uninsured, and vaginal delivery [18, 31–32, 34–41]. However, no report of the predictors of 12–week postpartum BP monitoring exists to date. The present study adds to the scant literature on this topic by examining predictors of poor adherence to BP monitoring within 3 months in postpartum HDP patients after discharge from the hospital in a multivariable model. Our study unravelled similar factors affecting attendance at the BP monitoring.
On the other hand, having delivered at a later median gestational age was first identified in our study as an independent risk factor associated with poor adherence to postpartum BP monitoring. The results of the ROC curve analysis showed that when delivery median gestational age ≥ 33.4 weeks, the postpartum HDP patients were less likely to adhere to BP monitoring after discharge. Traditionally, later gestational age of delivery indicated that females with less severe HDP tend not to pay enough attention to the BP monitoring after discharge. The effect of the delivery gestational age on poor adherence to BP monitoring needs, however, further research.
The major strengths of the present study are as follows. First, this is the first prospective cohort study report on the adherence to BP monitoring within 3 months after discharge from the hospital in postpartum discharged HDP patients. Second, we established a regression model with three factors to identify the poor adherence to BP monitoring, overcoming the problem that ROC curves for a single risk factor indicated that the predictive value was not significant. The predicted probability of this model had an AUC of 0.746 (P < 0.001) and a sensitivity and specificity of 66.5% and 71.1%, respectively, which means that the model had a high predictive value. Third, the present results are useful for clinical practice, and the established regression model helps to quickly identify patients who may be less likely to adhere to post-discharge BP monitoring, so that more targeted discharge education may be attempted for these patients to improve their adherence to BP monitoring.
There are, however, a few limitations to this study: (1) Our study analyzed risk factors of poor adherence to BP monitoring within 3 months after discharge from the hospital in postpartum discharged HDP patients, but it is possible that not all impact factors were included, such as data on prenatal care utilization, which was unavailable and had been identified as predictors of 7–10 days and 6-week postpartum BP monitoring [18, 30–41]. (2) The entire data came from the perinatal medical database, which is representative of the Suzhou region, but the demographic diversity of our cohort was narrow. (3) This is a single-center clinical study, so these findings have limited generalizability to populations that differ demographically or geographically. (4) In this study, follow-up was conducted mainly by telephone, with limited follow-up time and patient cooperation. Therefore, due to the small sample size used, it was not possible to observe the occurrence of cardiovascular events and readmission of patients after discharge from the hospital.
However, the above does not significantly affect the main results and conclusions of this study, but in the future better follow-up methods will be used, such as telehealth technology, to carry out multicenter clinical cohort studies with more impact factors included to analyze and evaluate the risk factors of the adherence to BP monitoring after discharge from the hospital and to assess the long-term outcomes such as hospital readmissions, maternal mortality, and future cardiovascular health in postpartum discharged HDP patients. Reported telehealth technologies for postpartum care include call-center driven BP management [42], combining home BP cuffs with text message reminders for remote postpartum BP monitoring, or providing a Genesis Touch tablet, automatic BP cuff, scale, and pulse oximeter that allow Bluetooth transmission of all home vitals synced on a daily basis to a central monitoring platform for 2–6 weeks [26, 43–44]. Data from these pilot studies indicate remote BP monitoring is entirely feasible and acceptable to patients and providers. It results in higher quality-adjusted years, a significant reduction in postpartum readmissions, 3.7% (8/214) versus 0.5% (1/214) [45]. Moreover, the average cost of telehealth was reported to be $309 per patient, and was cost–effective to a cost of $420 per patient. Meanwhile, telehealth could reduce health care costs in the US by approximately $31 million a year. [45].