Evaluation of different blood pressure assessment strategies and cutoff values to predict postpartum hypertension-related readmissions: a retrospective cohort study

Postpartum blood pressure control and the rate of readmission

BACKGROUND

Postpartum hypertension is a major contributor to the rising maternal mortality rates in the United States, with nearly half of maternal deaths occurring after delivery. Previous studies have found evidence that the maximum blood pressure reading during labor and delivery admission can predict readmission; however, the optimal blood pressure to reduce the need for readmissions and additional medical treatment in the postpartum period is not known.

OBJECTIVE

This study aimed to investigate the relationship between postpartum blood pressure control at discharge and readmission within the first 6 weeks after delivery.

STUDY DESIGN

Data were obtained from Cosmos, an electronic health record-based, Health Insurance Portability and Accountability Act-defined limited dataset that includes more than 1.4 million birth encounters. All birthing parents with blood pressure data after delivery were included. Demographic information, medications, and readmissions were queried from the dataset. Patients were grouped into categories based on blood pressure readings in the 24 hours before discharge (≥160/110, ≥150/100, ≥140/90, ≥130/80, ≥120/80, and <120/80 mm Hg). The readmission rates across these groups were compared. Planned subanalyses included stratification by the use of antihypertensive medications and a sensitivity analysis using the highest blood pressure during admission. Covariates included maternal age, preexisting diabetes mellitus or lupus erythematosus, and body mass index.

RESULTS

The analysis included 1,265,766 total birth encounters, 391,781 (30.9%) in the referent group (120/80 mm Hg), 392,592 (31.0%) in the group with <120/80 mm Hg, 249,414 (19.7%) in the group with ≥130/80 mm Hg, 16,125 (1.3%) in the group with ≥140/90 mm Hg, 50,659 (4.0%) in the group with ≥150/100 mm Hg, and 20,196 (1.6%) in the group with ≥160/110 mm Hg. In the first 6 weeks after delivery, readmission rates increased with higher blood pressure readings. More than 5% of postpartum patients with the highest blood pressure readings (≥160/110 mm Hg) were readmitted. These patients were almost 3 times more likely to be readmitted than patients whose highest blood pressure reading fell into the referent group (120/80 mm Hg) (odds ratio [OR], 2.90; 95% confidence interval, 2.69-3.12). Patients with blood pressures of >150/100 mm Hg (odds ratio, 2.72; 95% confidence interval, 2.58-2.87), >140/90 mm Hg (odds ratio, 2.03; 95% confidence interval, 1.95-2.11), and >130/80 mm Hg (odds ratio, 1.43; 95% confidence interval, 1.37-1.49) all had higher odds of readmission, whereas patients with a blood pressure of <120/80 mm Hg had a lower odds of readmission (odds ratio, 0.78; 95% confidence interval, 0.75-0.81). Patients who had higher blood pressures during admission but had improved control in the 24 hours before discharge had lower rates of readmission than those whose blood pressures remained elevated. In all blood pressure categories, patients who received an antihypertensive prescription had higher rates of readmission.

CONCLUSION

In this large, national dataset, blood pressure control at discharge and readmission in the postpartum period were significantly correlated. Our data should inform postpartum hypertension treatment goals and the role of remote monitoring programs in improving maternal safety.

Predictive modeling of postpartum blood pressure spikes

BACKGROUND

Hypertensive disorders of pregnancy are one of the leading causes of maternal morbidity and mortality worldwide. Management of these conditions can pose many clinical dilemmas and can be particularly challenging during the immediate postpartum period. Models for predicting and managing postpartum hypertension are necessary to help address this clinical challenge.

OBJECTIVE

This study aimed to evaluate predictive models of blood pressure spikes in the postpartum period and to investigate clinical management strategies to optimize care.

STUDY DESIGN

This was a retrospective cohort study of postpartum women who participated in remote blood pressure monitoring. A postpartum blood pressure spike was defined as a blood pressure measurement of ≥140/90 mm Hg while on an antihypertensive medication and a blood pressure measurement of ≥150/100 mm Hg if not on an antihypertensive medication. We identified 3 risk level patient clusters (low, medium, and high) when predicting patient risk for a blood pressure spike on postpartum days 3 to 7. The variables used in defining these clusters were peak systolic blood pressure before discharge, body mass index, patient systolic blood pressure per trimester, heart rate, gestational age, maternal age, chronic hypertension, and gestational hypertension. For each risk cluster, we focused on 2 treatments, namely (1) postpartum length of stay (<3 days or ≥3 days) and (2) discharge with or without blood pressure medications. We evaluated the effectiveness of the treatments in different subgroups of patients by estimating the conditional average treatment effect values in each cluster using a causal forest. Moreover, for all patients, we considered discharge with medication policies depending on different discharge blood pressure thresholds. We used a doubly robust policy evaluation method to compare the effectiveness of the policies.

RESULTS

A total of 413 patients were included, and among those, 267 (64.6%) had a postpartum blood pressure spike. The treatments for patients at medium and high risk were considered beneficial. The 95% confidence intervals for constant marginal average treatment effect for antihypertensive use at discharge were -3.482 to 4.840 and - 5.539 to 4.315, respectively; and for a longer stay they were -5.544 to 3.866 and -7.200 to 4.302, respectively. For patients at low risk, the treatments were not critical in preventing a blood pressure spike with 95% confidence intervals for constant marginal average treatment effect of 1.074 to 15.784 and -2.913 to 9.021 for the different treatments. We considered the option to discharge patients with antihypertensive use at different blood pressure thresholds, namely (1) ≥130 mm Hg and/or ≥80 mm Hg, (2) ≥140 mm Hg and/or ≥90 mm Hg, (3) ≥150 mm Hg and/or ≥ 100 mm Hg, or (4) ≥160 mm Hg and/or ≥ 110 mm Hg. We found that policy (2) was the best option with P<.05.

CONCLUSION

We identified 3 possible strategies to prevent outpatient blood pressure spikes during the postpartum period, namely (1) medium- and high-risk patients should be considered for a longer postpartum hospital stay or should participate in daily home monitoring, (2) medium- and high-risk patients should be prescribed antihypertensives at discharge, and (3) antihypertensive treatment should be prescribed if patients are discharged with a blood pressure of ≥140/90 mm Hg.

Moving the needle: Quality improvement strategies to achieve guideline-concordant care of obstetric patients with severe hypertension

OBJECTIVES

To improve timely treatment and follow-up of birthing individuals with severe hypertension.

STUDY DESIGN

A quality improvement (QI) initiative was implemented at an academic tertiary care center in the United States of America for individuals with obstetric hypertensive emergencies. Statistical process control charts were utilized to track process measures and interventions tested through plan-do-study-act cycles. Measures were disaggregated by race and ethnicity to identify and improve disparities.

MAIN OUTCOME MEASURES

Treatment of hypertensive events within 60 min, receipt of blood pressure (BP) device at discharge and completed postpartum follow-up BP check within 7 days of discharge.

RESULTS

All process measures showed statistically significant improvements. The primary process measure, timely treatment of hypertensive emergencies, improved from 29 % to 76 %. Receipt of BP device improved from 37 % to 91 % and follow-up BP checks from 58 % to 81 %. No racial or ethnic disparities were noted at baseline or after interventions. Readmission rates within 6 weeks of delivery increased from 2.3 % to 6.1 % for the cohort with no severe morbidity or mortality events after discharge. Strategies associated with improvement included project launch with establishment of the "why," telehealth, simulation, a video display of quality metrics on the birthing unit, promoting BP cuff access, and automated orders.

CONCLUSIONS

This comprehensive QI initiative provides novel improvement strategies for the management of individuals with severe hypertensive disorders of pregnancy for the timely treatment of severe BP, attainment of home BP devices, and follow-up after discharge. Quality improvement methodology is practical and essential for achieving guideline-concordant care.

Ensuring safe and equitable discharge: a quality improvement initiative for individuals with hypertensive disorders of pregnancy

OBJECTIVE

To improve timely and equitable access to postpartum blood pressure (BP) monitoring in individuals with hypertensive disorders of pregnancy (HDP).

METHODS

A quality improvement initiative was implemented at a large academic medical centre in the USA for postpartum individuals with HDP. The primary aim was to increase completed BP checks within 7 days of hospital discharge from 40% to 70% in people with HDP in 6 months. Secondary aims included improving rates of scheduled visits, completed visits within 3 days for severe HDP and unattended visits. The balancing measure was readmission rate. Statistical process control charts were used, and data were stratified by race and ethnicity. Direct feedback from birthing individuals was obtained through phone interviews with a focus on black birthing people after a racial disparity was noted in unattended visits.

RESULTS

Statistically significant improvements were noted across all measures. Completed and scheduled visits within 7 days of discharge improved from 40% to 76% and 61% to 90%, respectively. Completed visits within 3 days for individuals with severe HDP improved from 9% to 49%. The unattended visit rate was 26% at baseline with non-Hispanic black individuals 2.3 times more likely to experience an unattended visit than non-Hispanic white counterparts. The unattended visit rate decreased to 15% overall with an elimination of disparity. A need for BP devices at discharge and enhanced education for black individuals was identified through patient feedback.

CONCLUSION

Timely follow-up of postpartum individuals with HDP is challenging and requires modification to our care delivery. A hospital-level quality improvement initiative using birthing individual and frontline feedback is illustrated to improve equitable, person-centred care.

Risk of postpartum readmission after hypertensive disorder of pregnancy and variation by discharge antihypertensive medication prescription

BACKGROUND

Patients with hypertensive disorders of pregnancy have a high rate of postpartum readmission.

OBJECTIVE

This study aimed to evaluate whether the type of antihypertensive medication prescribed at discharge was associated with postpartum readmission after a hypertensive disorder of pregnancy.

STUDY DESIGN

This was a retrospective cohort study of 57,254 pregnancies complicated by hypertensive disorders of pregnancy between 2012 and 2018 in the electronic obstetrical database of Kaiser Permanente Northern California. Postpartum readmissions occurred within 6 weeks after discharge from delivery hospitalization. Cox regression models were used to evaluate the association between the type of antihypertensive medication prescription at discharge (none, labetalol only, nifedipine only, or 2 or more antihypertensive medications) and postpartum readmission, adjusted for type of hypertensive disorder of pregnancy, final inpatient systolic and diastolic blood pressures, age, body mass index, mode of delivery, insurance status, race and ethnicity, delivery facility, comorbidity score, smoking, preterm delivery, parity, and Neighborhood Deprivation Index.

RESULTS

Among eligible patients with a hypertensive disorder of pregnancy, 1696 (3.0%) were readmitted within 6 weeks. Approximately 86% of patients were discharged without a prescription for antihypertensive medication; among those discharged with a prescription for antihypertensive medication, most were prescribed either labetalol only (54%) or nifedipine only (30%). The unadjusted readmission risk was the highest for patients discharged with a prescription for labetalol only (7.6%), lower for those discharged with a prescription for nifedipine only (3.6%) or 2 or more antihypertensive medications (3.2%), and the lowest for those discharged without a prescription for antihypertensive medication (2.5%). In the adjusted models, compared with discharge without a prescription for antihypertensive medication, discharge with a prescription for labetalol only was associated with a 63% (hazard ratio, 1.63; 95% confidence interval, 1.41-1.88) greater incidence of postpartum readmission, and discharge with a prescription for nifedipine only and discharge with a prescription for 2 or more antihypertensive medications were associated with 26% (hazard ratio, 0.74; 95% confidence interval, 0.59-0.93) and 47% (hazard ratio, 0.53; 95% confidence interval, 0.38-0.74) lower incidence of postpartum readmission, respectively. There was no strong evidence to suggest that the effect of the type of antihypertensive medication at discharge on the incidence of readmission varied by race and ethnicity (interaction P=.88). The results indicating an elevated risk associated with labetalol use were consistent in models that excluded patients with prepregnancy hypertension.

CONCLUSION

Discharge with a prescription for nifedipine alone or multiple antihypertensive medications (vs no medication) was associated with a lower incidence of readmission, whereas discharge with a prescription for labetalol alone was associated with an elevated readmission incidence. A large-scale, prospective research to compare the effectiveness of commonly prescribed hypertension medications at discharge is warranted.

Standardized Clinical Assessment and Management Plan to Reduce Readmissions for Postpartum Hypertension

OBJECTIVE

To evaluate the effect of a postpartum hypertension standardized clinical assessment and management plan on postpartum readmissions and emergency department (ED) visits.

METHODS

We conducted a prospective cohort study of patients with postpartum hypertension (either chronic hypertension or hypertensive disorders of pregnancy) who delivered at a single tertiary care center for 6 months after enacting an institution-wide standardized clinical assessment and management plan (postintervention group). Patients in the postintervention group were compared with patients in a historical control group. The standardized clinical assessment and management plan included 1) initiation or uptitration of medication for any blood pressure (BP) higher than 150/100 mm Hg or any two BPs higher than 140/90 mm Hg within a 24-hour period, with the goal of achieving normotension (BP lower than 140/90 mm Hg) in the 12 hours before discharge; and 2) enrollment in a remote BP monitoring system on discharge. The primary outcome was postpartum readmission or ED visit for hypertension. Multivariable logistic regression was used to evaluate the association between standardized clinical assessment and management plan and the selected outcomes. A sensitivity analysis was performed with propensity score weighting. A planned subanalysis in the postintervention cohort identified risk factors associated with requiring antihypertensive uptitration after discharge. For all analyses, the level of statistical significance was set at P<.05.

RESULTS

Overall, 390 patients in the postintervention cohort were compared with 390 patients in a historical control group. Baseline demographics were similar between groups with the exception of lower prevalence of chronic hypertension in the postintervention cohort (23.1% vs 32.1%, P=.005). The primary outcome occurred in 2.8% of patients in the postintervention group and in 11.0% of patients in the historical control group (adjusted odds ratio [aOR] 0.24, 95% CI 0.12-0.49, P<.001). A matched propensity score analysis controlling for chronic hypertension similarly demonstrated a significant reduction in the incidence of the primary outcome. Of the 255 patients (65.4%) who were compliant with outpatient remote BP monitoring, 53 (20.8%) had medication adjustments made per protocol at a median of 6 days (interquartile range 5-8 days) from delivery. Non-Hispanic Black race (aOR 3.42, 95% CI 1.68-6.97), chronic hypertension (aOR 2.09, 95% CI 1.13-3.89), having private insurance (aOR 3.04, 95% CI 1.06-8.72), and discharge on antihypertensive medications (aOR 2.39, 95% CI 1.33-4.30) were associated with requiring outpatient adjustments.

CONCLUSION

A standardized clinical assessment and management plan significantly reduced postpartum readmissions and ED visits for patients with hypertension. Close outpatient follow-up to ensure appropriate medication titration after discharge may be especially important in groups at high risk for readmission.

Society for Maternal-Fetal Medicine Special Statement: A critique of postpartum readmission rate as a quality metric

Hospital readmission is considered a core measure of quality in healthcare. Readmission soon after hospital discharge can result from suboptimal care during the index hospitalization or from inadequate systems for postdischarge care. For many conditions, readmission is associated with a high rate of serious morbidity and potentially avoidable costs. In obstetrics, for postpartum care specifically, hospitals and payers can easily track the rate of maternal readmission after childbirth and may seek to incentivize obstetricians, maternal-fetal medicine specialists, or provider groups to reduce the rate of readmission. However, this practice has not been shown to improve outcomes or reduce harm. There are major concerns with incentivizing providers to reduce postpartum readmissions, including the lack of a standardized metric, a baseline rate of 1% to 2% that is too low to accurately discriminate between random variation and controllable factors, the need for risk adjustment that greatly complicates rate calculations, the potential for bias depending on the duration of the follow-up interval, the potential for the "gaming" of the metric, the lack of evidence that obstetrical providers can influence the rate, and the potential for unintended harm in the vulnerable postpartum population. Until these problems are adequately addressed, maternal readmission rate after a childbirth hospitalization currently has limited utility as a metric for quality or performance improvement or as a factor to adjust provider reimbursement.

Postpartum Outcomes With Systematic Treatment and Management of Postpartum Hypertension

OBJECTIVE

To test the ability of a hospital-wide, bundled quality-improvement initiative to improve postpartum maternal blood pressure control and adherence to postpartum follow-up among patients with hypertensive disorders of pregnancy.

METHODS

This quality-improvement initiative consisted of a bundle of clinical interventions including health care professional and patient education, a dedicated nurse educator, and protocols for postpartum hypertensive disorders of pregnancy care in the inpatient, outpatient and readmission setting. We implemented this initiative in patients with hypertensive disorders of pregnancy starting in January 2019 at the University of Chicago. The study period was divided into four periods, which correspond to preintervention, distinct bundle roll outs, and postintervention. Our primary outcome was postpartum hypertension visit adherence. Secondary outcomes included blood pressure values and antihypertensive medication use in the immediate postpartum and outpatient postpartum time periods. We then stratified our outcomes by race to assess whether the effect size differed.

RESULTS

A total of 926 patients who delivered between September 2018 and November 2019 were included. Postpartum hypertension visit adherence improved from preintervention period compared with the full implementation period (33.5% vs 59.4%, P<.001). Blood pressure in the first 24 hours postpartum decreased from preintervention compared with full implementation (preintervention median [interquartile range] systolic blood pressure 149 mm Hg [138, 159] vs 137 [131, 146] in postimplementation; P<.001). After implementation, fewer patients experienced a blood pressure of 140/90 mm Hg or higher at the first postpartum blood pressure check, when compared with preintervention (39.1% vs 18.5%, P=.004). The effect size did not differ by race.

CONCLUSION

A bundled quality-improvement initiative for patients with hypertensive disorders of pregnancy was associated with improved postpartum visit adherence and blood pressure control in the postpartum period.