The relative effects of patient and hospital factors on postpartum readmissions

Inpatient midwifery staffing levels and postpartum readmissions: a retrospective multicentre longitudinal study

BACKGROUND

Preventing readmission to hospital after giving birth is a key priority, as rates have been rising along with associated costs. There are many contributing factors to readmission, and some are thought to be preventable. Nurse and midwife understaffing has been linked to deficits in care quality. This study explores the relationship between staffing levels and readmission rates in maternity settings.

METHODS

We conducted a retrospective longitudinal study using routinely collected individual patient data in three maternity services in England from 2015 to 2020. Data on admissions, discharges and case-mix were extracted from hospital administration systems. Staffing and workload were calculated in Hours Per Patient day per shift in the first two 12-hour shifts of the index (birth) admission. Postpartum readmissions and staffing exposures for all birthing admissions were entered into a hierarchical multivariable logistic regression model to estimate the odds of readmission when staffing was below the mean level for the maternity service.

RESULTS

64 250 maternal admissions resulted in birth and 2903 mothers were readmitted within 30 days of discharge (4.5%). Absolute levels of staffing ranged between 2.3 and 4.1 individuals per midwife in the three services. Below average midwifery staffing was associated with higher rates of postpartum readmissions within 7 days of discharge (adjusted OR (aOR) 1.108, 95% CI 1.003 to 1.223). The effect was smaller and not statistically significant for readmissions within 30 days of discharge (aOR 1.080, 95% CI 0.994 to 1.174). Below average maternity assistant staffing was associated with lower rates of postpartum readmissions (7 days, aOR 0.957, 95% CI 0.867 to 1.057; 30 days aOR 0.965, 95% CI 0.887 to 1.049, both not statistically significant).

CONCLUSION

We found evidence that lower than expected midwifery staffing levels is associated with more postpartum readmissions. The nature of the relationship requires further investigation including examining potential mediating factors and reasons for readmission in maternity populations.

Postpartum readmission risk: a comparison between stillbirths and live births

BACKGROUND

Stillbirth occurs more commonly among pregnant people with comorbid conditions and obstetrical complications. Stillbirth also independently increases maternal morbidity and imparts a psychosocial hazard when compared with live birth. These distinct needs and burden may increase the risk for postpartum readmission after stillbirth.

OBJECTIVE

This study aimed to examine the risk for maternal postpartum readmission after stillbirth in comparison with live birth and to identify indications for readmission and the associated risk factors.

STUDY DESIGN

This was a retrospective cohort of patients with singleton stillbirths or live births, delivered at ≥20 weeks' gestation, who were identified from the 2019 Nationwide Readmissions Database. The primary outcome was all-cause readmission within 6 weeks of discharge from the childbirth hospitalization. The association between stillbirth (vs live birth) and risk for readmission was assessed using multivariable regression models with adjustment for maternal age, sociodemographic characteristics, maternal and obstetrical conditions, and delivery characteristics. Within the stillbirth group, risk factors for readmission were further examined using multivariable regression. The secondary outcomes included principal indication for readmission (categorized based on principal diagnosis code of the readmission hospitalization) and timing of readmission (number of weeks after childbirth hospitalization). Differences in these secondary outcomes were compared between the stillbirth and live birth groups using chi-square tests. All analyses accounted for the complex sample design to generate nationally representative estimates.

RESULTS

Postpartum readmission occurred in 2.7% of 16,636 patients with stillbirths, whereas it occurred in 1.6% of 2,870,677 patients with live births (unadjusted risk ratio, 1.65; 95% confidence interval, 1.47-1.86). The higher risk for readmission after stillbirth (vs live birth) persisted after adjusting for maternal, obstetrical, and delivery characteristics (adjusted risk ratio, 1.27; 95% confidence interval, 1.11-1.46). The distribution of principal indication for readmission differed after stillbirth and after live birth and included hypertension (30.2% vs 39.5%; unadjusted risk ratio, 0.76; 95% confidence interval, 0.63-0.93), mental health or substance use disorders (6.8% vs 3.6%; unadjusted risk ratio, 1.90; 95% confidence interval, 1.15-3.16), and venous thromboembolism (5.8% vs 2.0%; unadjusted risk ratio, 2.87; 95% confidence interval, 1.60-5.17). Among patients with stillbirths, 56.0% of readmissions occurred within 1 week, 71.8% within 2 weeks, and 88.1% within 4 weeks; the timing of readmission did not differ significantly between the stillbirth and live birth cohorts. Pregestational diabetes (adjusted risk ratio, 1.87; 95% confidence interval, 1.20-2.93), gestational diabetes (adjusted risk ratio, 1.67; 95% confidence interval, 1.03-2.71), hypertensive disorders of pregnancy (adjusted risk ratio, 1.80; 95% confidence interval, 1.31-2.47), obesity (adjusted risk ratio, 1.46; 95% confidence interval, 1.01-2.12), and primary cesarean delivery (adjusted risk ratio, 1.74; 95% confidence interval, 1.17-2.58) were associated with a higher risk for readmission after stillbirth, whereas higher household income was associated with a lower risk for readmission (eg, adjusted risk ratio for income ≥$82,000 vs $1-$47,999, 0.48; 95% confidence interval, 0.30-0.77).

CONCLUSION

When compared with live births, the risk for postpartum readmission was higher after stillbirths, even after adjustment for differences in the patient demographic and clinical characteristics. Readmission for mental health or substance use disorders and venous thromboembolism is more common after stillbirths than after live births.

Assessing Racial Disparities in Access, Use, and Outcomes for Pregnant and Postpartum Veterans and Their Infants in Veterans Health Administration

Objective: Limited population-based data examines racial disparities among pregnant and postpartum Veterans. Our objective was to determine whether Black/white racial disparities in health care access, use, and Veteran and infant outcomes are present among pregnant and postpartum Veterans and their infants using Veterans Health Administration (VA) care. Methods: The VA National Veteran Pregnancy and Maternity Care Survey included all Veterans with a VA paid live birth between June 2018 and December 2019. Participants could complete the survey online or by telephone. The independent variable was self-reported race. Outcomes included timely initiation of prenatal care, perceived access to timely prenatal care, attendance at a postpartum check-up, receipt of needed mental health care, cesarean section, postpartum rehospitalization, low birthweight, preterm birth, admission to a neonatal intensive care unit, and breastfeeding. Nonresponse weighted general linear models with a log-link were used to examine associations of race with outcomes. Cox regression was used to examine the association of race with duration of breastfeeding. Models adjusted for age, ethnicity, urban versus rural residence, and parity. Results: The analytic sample consisted of 1,220 Veterans (Black n = 916; white n = 304) representing 3,439 weighted responses (Black n = 1,027; white n = 2,412). No racial disparities were detected for health care access or use. Black Veterans were more likely than white Veterans to have a postpartum rehospitalization (RR 1.67, 95% CI: 1.04-2.68) and a low-birthweight infant (RR 1.67, 95% CI: 1.20-2.33). Conclusion: While no racial disparities were detected for health care access and use, we identified disparities in postpartum rehospitalization and low birthweight, underscoring that access is not sufficient for ensuring health equity.

Postpartum Hospital Readmissions With and Without Severe Maternal Morbidity Within 1 Year of Birth, Oregon, 2012-2017

Postpartum readmissions (PPRs) represent a critical marker of maternal morbidity after hospital childbirth. Most severe maternal morbidity (SMM) events result in a hospital admission, but most PPRs do not have evidence of SMM. Little is known about PPR and SMM beyond the first 6 weeks postpartum. We examined the associations of maternal demographic and clinical factors with PPR within 12 months postpartum. We categorized PPR as being with or without evidence of SMM to assess whether risk factors and timing differed. Using the Oregon All Payer All Claims database, we analyzed hospital births from 2012-2017. We used log-binomial regression to estimate associations between maternal factors and PPR. Our final analytical sample included 158,653 births. Overall, 2.6% (n = 4,141) of births involved at least 1 readmission within 12 months postpartum (808 (19.5% of PPRs) with SMM). SMM at delivery was the strongest risk factor for PPR with SMM (risk ratio (RR) = 5.55, 95% confidence interval (CI): 4.14, 7.44). PPR without SMM had numerous risk factors, including any mental health diagnosis (RR = 2.10, 95% CI: 1.91, 2.30), chronic hypertension (RR = 2.17, 95% CI: 1.85, 2.55), and prepregnancy diabetes (RR = 2.85, 95% CI: 2.47, 3.30), all which were on par with SMM at delivery (RR = 1.89, 95% CI: 1.49, 2.40).

The use of loop diuretics in the context of hypertensive disorders of pregnancy: a systematic review and meta-analysis

AIMS

Addressing volume expansion may improve the management of hypertension across the pregnancy continuum. We conducted a systematic review to summarize the evidence on the use of loop diuretics in the context of hypertensive disorders during pregnancy and the postpartum period.

METHODS AND RESULTS

Medline, Embase, Cochrane library, ClinicalTrials.gov, and Google Scholar were searched for original research articles published up to 29 June 2021. Of the 2801 results screened, 15 studies were included: eight randomized controlled trials, six before-after studies, and one cohort study. Based on random effects meta-analysis of before-after studies, antepartum use of loop diuretics was associated with lower DBP [mean difference -17.73 mmHg, (95% confidence intervals -34.50 to -0.96); I2 = 94%] and lower cardiac output [mean difference -0.75 l/min, (-1.11 to -0.39); I2 = 0%], with no difference in SBP, mean arterial pressure, heart rate, or total peripheral resistance. Meta-analysis of randomized controlled trials revealed that postpartum use of loop diuretics was associated with decreased need for additional antihypertensive patients [relative risk 0.69, (0.50-0.97); I2 = 14%], and an increased duration of hospitalization [mean difference 8.80 h, (4.46-13.14); I2 = 83%], with no difference in the need for antihypertensive therapy at hospital discharge, or persistent postpartum hypertension.

CONCLUSION

Antepartum use of loop diuretics lowered DBP and cardiac output, while their postpartum use reduced the need for additional antihypertensive medications. There was insufficient evidence to suggest a clear benefit. Future studies focusing on women with hypertensive pregnancy disorders who may most likely benefit from loop diuretics are required.

Development of a risk prediction score for acute postpartum care utilization

BACKGROUND

Acute postpartum care utilization and readmissions are increasing in the United States and contribute significantly to maternal morbidity, mortality, and healthcare costs. Currently, there are limited data on the prediction of patients who will require acute postpartum care utilization.

OBJECTIVE

To develop and validate a risk prediction model for acute postpartum care utilization.

STUDY DESIGN

A retrospective cohort study of delivery hospitalizations with a linked birth certificate and discharge records in California from 2011 to 2015 was divided into a training and testing set for analysis and validation. Predictive models for acute postpartum care utilization using demographic, comorbidity, obstetrical complication, and other factors were developed using a backward stepwise logistic regression on training data. A risk score for acute postpartum care utilization was developed using beta coefficients from the factors remaining in the final multivariable model. Risk scores were validated using the testing dataset.

RESULTS

The final sample included 2,045,988 delivery hospitalizations with an acute postpartum care utilization rate of 7.6% in both training and testing cohorts. Twenty-two risk factors were identified for the final multivariable model, including several that were associated with two or more increased odds of acute care utilization (public insurance, postpartum hemorrhage, extremes of maternal age). The mean risk score was 2.45, conferring a 15 times higher risk of acute postpartum care utilization compared to those with a risk score <1 (RR 15.4, 95% CI: 11.0, 21.7). Demographics and test performance characteristics were comparably similar in predictive capability in both models (0.67 in both the training and testing cohorts).

CONCLUSION

Risk factors that are identifiable before discharge can be used to create a cumulative risk score to stratify patients at the lowest and highest risk of acute postpartum care utilization with satisfactory accuracy. External validation and the addition of other granular clinical variables are necessary to validate the feasibility of use.

Postpartum Readmission for Hypertension After Discharge on Labetalol or Nifedipine

OBJECTIVE

To assess whether readmission for hypertension by 6 weeks postpartum differed between patients discharged on nifedipine or labetalol.

METHODS

This cohort study included patients with delivery admissions from 2006 to 2017 who were discharged from the hospital on nifedipine or labetalol and were included in a large, national adjudicated claims database. We identified patients' discharge medication based on filled outpatient prescriptions. We compared rates of hospital readmission for hypertension between patients discharged postpartum on labetalol alone, nifedipine alone, or combined nifedipine and labetalol. Patients with chronic hypertension without superimposed preeclampsia were excluded. Comparisons based on medication were performed using logistic regression models with adjustment for prespecified confounders. Comparisons were also stratified by hypertensive disorder of pregnancy severity.

RESULTS

Among 1,582,335 patients overall, 14,112 (0.89%) were discharged postpartum on labetalol, 9,001 (0.57%) on nifedipine, and 1,364 (0.09%) on both medications. Postpartum readmissions for hypertension were more frequent for patients discharged on labetalol compared with nifedipine (641 patients vs 185 patients, 4.5% vs 2.1%, adjusted odds ratio [aOR] 1.63, 95% CI 1.43-1.85). Readmissions for hypertension were more frequent for patients discharged on labetalol compared with nifedipine for both mild (4.5% vs 2.7%, aOR 1.57, 95% CI 1.29-1.93) and severe hypertensive disorders of pregnancy (261 patients vs 72 patients, 5.7% vs 3.2%, aOR 1.63, 95% CI 1.43-1.85). Readmissions for hypertension were more frequent on combined nifedipine and labetalol compared with nifedipine (3.1% vs 2.1%), but the odds were lower after confounder adjustment (aOR 0.80, 95% CI 0.64-0.99).

CONCLUSION

Postpartum discharge on labetalol was associated with increased risk of readmission for hypertension compared with discharge on nifedipine.

Development and Internal Validation of a Risk Prediction Model for Acute Cardiovascular Morbidity in Preeclampsia

BACKGROUND

Persons with preeclampsia are at increased short-term risk of adverse cardiovascular outcomes during pregnancy and the early postpartum period. We aimed to develop and internally validate a risk assessment tool to predict acute cardiovascular morbidity in preeclampsia.

METHODS

The study was conducted at an academic obstetric hospital. Participants with preeclampsia at delivery between 2007 and 2017 were included. A model to predict acute cardiovascular morbidity at delivery and within 6 weeks postpartum was developed and evaluated. The primary composite outcome included pulmonary edema/acute heart failure, myocardial infarction, aneurysm, cardiac arrest/ventricular fibrillation, heart failure/arrest during surgery or procedure, cerebrovascular disorders, cardiogenic shock, conversion of cardiac rhythm, and difficult-to-control severe hypertension. We assessed model discrimination and calibration. We used bootstrapping for internal validation.

RESULTS

4,171 participants with preeclampsia were included. The final model comprised 8 variables. Predictors positively associated with acute cardiovascular morbidity (presented as odds ratio [OR] with 95% confidence interval [CI]) were: gestational age at delivery (20-36 weeks 5.36 [3.67, 7.82]; 37-38 weeks 1.75 [1.16, 2.64]), maternal age (≥40 years 1.65 [1.00, 2.72]; 35-39 years 1.49 [1.07, 2.09]), and prior cesarean delivery (1.47, [1.01, 2.13]). The model had an area under the receiver operating characteristic curve of 0.72 (95% CI [0.69, 0.74]). Moreover, it was adequately calibrated and performed well on internal validation.

CONCLUSIONS

This risk prediction tool identified women with preeclampsia at highest risk of acute cardiovascular morbidity. If externally validated, this tool may facilitate early interventions aimed at preventing adverse cardiovascular outcomes in pregnancy and postpartum.

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.

Reduced rate of postpartum readmissions among homeless compared with non-homeless women in New York: a population-based study using serial, cross-sectional data

Objective

To assess differences in rates of postpartum hospitalisations among homeless women compared with non-homeless women.

Design

Cross-sectional secondary analysis of readmissions and emergency department (ED) utilisation among postpartum women using hierarchical regression models adjusted for age, race/ethnicity, insurance type during delivery, delivery length of stay, maternal comorbidity index score, other pregnancy complications, neonatal complications, caesarean delivery, year fixed effect and a birth hospital random effect.

Setting

New York statewide inpatient and emergency department databases (2009–2014).

Participants

82 820 and 1 026 965 postpartum homeless and non-homeless women, respectively.

Main outcome measures

Postpartum readmissions (primary outcome) and postpartum ED visits (secondary outcome) within 6 weeks after discharge date from delivery hospitalisation.

Results

Homeless women had lower rates of both postpartum readmissions (risk-adjusted rates: 1.4% vs 1.6%; adjusted OR (aOR) 0.87, 95% CI 0.75 to 1.00, p=0.048) and ED visits than non-homeless women (risk-adjusted rates: 8.1% vs 9.5%; aOR 0.83, 95% CI 0.77 to 0.90, p<0.001). A sensitivity analysis stratifying the non-homeless population by income quartile revealed significantly lower hospitalisation rates of homeless women compared with housed women in the lowest income quartile. These results were surprising due to the trend of postpartum hospitalisation rates increasing as income levels decreased.

Conclusions

Two factors likely led to lower rates of hospital readmissions among homeless women. First, barriers including lack of transportation, payment or childcare could have impeded access to postpartum inpatient and emergency care. Second, given New York State’s extensive safety net, discharge planning such as respite and sober living housing may have provided access to outpatient care and quality of life, preventing adverse health events. Additional research using outpatient data and patient perspectives is needed to recognise how the factors affect postpartum health among homeless women. These findings could aid in lowering readmissions of the housed postpartum population.

Contributors to disparities in postpartum readmission rates between safety-net and non-safety-net hospitals: A decomposition analysis

BACKGROUND

Safety-net hospitals (SNHs) treat more maternal patients with risk factors for postpartum readmission.

OBJECTIVE

To assess how patient, hospital, and community characteristics explain the SNH/non-SNH disparity in postpartum readmission rates.

DESIGN

A linear probability model assessed covariates associated with postpartum readmissions. Oaxaca-Blinder decomposition estimates quantified the contribution of covariates to the SNH/non-SNH disparity in postpartum readmission rates.

SETTING

Healthcare Cost and Utilization Project 2016-2018 State Inpatient Databases from 25 states.

PARTICIPANTS

3.5 million maternal delivery stays.

MEASUREMENTS

The outcome was inpatient readmission within 42 days of delivery. SNHs had a share of Medicaid/uninsured stays in the top quartile. A range of patient, hospital, and community characteristics was considered as covariates.

RESULTS

The unadjusted postpartum readmission rate was 4.2 per 1000 index deliveries higher at SNHs than at non-SNHs (19.1 vs. 14.9, p < .001). Adjustment reduced the risk difference to 0.65 per 1000 (95% confidence interval [CI]: -0.14, 1.44). Patient (66%), hospital (14%), and community (4%) characteristics explained 84% of the disparity. The single largest contributors to the disparity were race/ethnicity (20%), hypertension (12%), hospital preterm delivery rate (10%), and preterm delivery (7%). Collectively, patient comorbidities explained 31% of the disparity.

CONCLUSION

Higher postpartum readmission rates at SNHs versus non-SNHs were largely due to differences in the patient mix rather than hospital factors. Hospital initiatives are needed to reduce the risk of postpartum readmissions among SNH patients. Improving factors that contribute to the disparity, including underlying health conditions and health inequities associated with race, requires enduring investments in public health.

Disparities in Obstetric Readmissions: A Multistate Analysis, 2007-2014

OBJECTIVE

Hospital readmissions are generally higher among racial-ethnic minorities and patients of lower socioeconomic status. However, this has not been widely studied in obstetrics. The aim of the study is to determine 30-day postpartum readmission rates by patient-level social determinants of health: race ethnicity, primary insurance payer, and median income, independently and as effect modifiers.

STUDY DESIGN

Using state inpatient databases from the health care cost and utilization project from 2007 to 2014, we queried all deliveries. To produce accurate estimates of the effects of parturients' social determinants of health on readmission odds while controlling for confounders, generalized linear mixed models (GLMMs) were used. Additional models were generated with interaction terms to highlight any associations and their effect on the outcome. Adjusted odds ratios (aOR) with 95% confidence intervals are reported.

RESULTS

There were 5,129,867 deliveries with 79,260 (1.5%) 30-day readmissions. Of these, 947 (1.2%) were missing race ethnicity. Black and Hispanic patients were more likely to be readmitted within 30 days of delivery, as compared with White patients (p < 0.001 and p < 0.05, respectively). Patients with government insurance were more likely to be readmitted than those with private insurance (p < 0.001). Patients living in the second quartile of median income were also more likely to be readmitted than those living in other quartiles (p < 0.05). Using GLMMs, we observed that Black patients with Medicare were significantly more likely to get readmitted as compared with White patients with private insurance (aOR 2.78, 95% CI 2.50-3.09, p < 0.001). Similarly, Black patients living in the fourth (richest) quartile of median income were more likely to get readmitted, even when compared with White patients living in the first (poorest) quartile of median income (aOR 1.48, 95% CI 1.40-1.57, p < 0.001).

CONCLUSION

Significant racial-ethnic disparities in obstetric readmissions were observed, particularly in Black patients with government insurance and even in Black patients living in the richest quartile of median income.

KEY POINTS

· Using generalized linear mixed models, we observed significant interactions.. · Government-insured Black patients were 2.78X more likely to be readmitted.. · The wealthiest Black patients were still 1.48X more likely to be readmitted..

Association between hospital-level cesarean delivery rates and severe maternal morbidity and unexpected newborn complications

BACKGROUND

Although there are many indications for a cesarean delivery, the "optimal" cesarean delivery rate is unknown. Neonatal and maternal morbidity have largely not been considered in the generation of hospital-level cesarean delivery rate targets.

OBJECTIVE

We sought to examine if the widely adopted and reported markers of maternal and neonatal morbidity were associated with hospital cesarean delivery rates to provide context for potential comparison and consideration for defining cesarean delivery rate targets. We hypothesized that hospitals with higher cesarean delivery rates would have increased rates of severe maternal morbidity, though we were less certain of the associations of the cesarean delivery rates with unexpected newborn complications.

STUDY DESIGN

This is a cross-sectional, ecological study using data from the 2016 Nationwide Readmission Database of hospitals with at least 100 deliveries per year. The exposure of interest was hospital cesarean delivery rate. The outcomes were (1) severe maternal morbidity with and without transfusion-in accordance with the Centers for Disease Control and Prevention's definition, and (2) neonatal morbidity-defined using The Joint Commission's Perinatal Quality metric of moderate and severe unexpected newborn complications among term, singleton, and nonanomalous neonates. Before assuming a single linear relationship to model the associations between morbidity and cesarean delivery rates, the Joinpoint Regression Analysis program was used to examine for potential splines in the relationships with both severe maternal morbidity (with and without transfusion) and severe and moderate unexpected newborn complications. Poisson regression model was then used to determine the association between morbidity and cesarean delivery rates.

RESULTS

The analysis included 831,111 deliveries from 621 hospitals. The mean cesarean delivery rate was 30.5%. The median severe maternal morbidity rate was 1.40 per 100 deliveries (interquartile range, 0.71-2.21 per 1000 deliveries). Excluding transfusion, the median severe maternal morbidity rate was 0.47 per 100 deliveries (interquartile range, 0.22-0.73 per 100 deliveries). The median rate of severe and moderate unexpected newborn complications was 1.01 per 100 low-risk newborns (interquartile range, 0.64-1.69 per 100 low-risk newborns) and 1.79 per 1000 low-risk newborns (interquartile range, 0.94-2.93 per 100 low-risk newborns), respectively. In the unadjusted analysis, every percentage point increase in a hospital's cesarean delivery rate was associated with a 3.4% (95% confidence interval, 2.3%-4.4%) and a 2.3% (95% confidence interval, 1.0%-3.5%) increase in severe maternal morbidity including and excluding transfusion, respectively. After adjustment for the case mix and hospital factors, only the relationship with severe maternal morbidity including transfusion remained significant: 3.3% (95% confidence interval, 1.7%-4.9%) increase in severe maternal morbidity per 1 percentage point increase in the cesarean delivery rate. There was no observed association between cesarean delivery rates and unexpected newborn complications CONCLUSION: Severe maternal morbidity and unexpected newborn complications occur in fewer than 5 in 100 births. Findings from this analysis of hospitals with cesarean delivery rates ranging from 6.8%-56.3% suggest that those with lower cesarean delivery rates have lower severe maternal morbidity (which includes transfusion) and similar unexpected newborn complications compared with hospitals with higher cesarean delivery rates. This work may provide a helpful context to providers, hospitals, and policymakers who are measuring and reporting outcomes. Regarding neonatal morbidity in particular, the Joint Commission manual notes that the unexpected newborn complication metric was specifically designed to be compared against maternal-focused metrics such as cesarean delivery rates. More work is needed to define and identify appropriate measures of maternal and neonatal morbidity for these types of comparisons.

Uncaptured rates of postpartum venous thromboembolism: a US national analysis

OBJECTIVE

To quantify the proportion of postpartum venous thromboembolism (VTE) readmissions, including those that occur at different hospitals from index admission, and describe risk factors for this outcome.

DESIGN

Retrospective observational study.

SETTING

US hospitals included in the Nationwide Readmissions Database.

SAMPLE

A total of 3 719 238 patients >14 years of age with a delivery-associated hospitalisation in 2014.

METHODS

Univariate analysis was performed to identify patient and hospital factors associated with readmissions. Significant factors were included in multivariate logistic regression to identify independent risk factors. Results were weighted for national estimates.

MAIN OUTCOME MEASURES

Readmission with VTE to both index and different hospitals at 30, 60 and 90 days.

RESULTS

The VTE cumulative readmission rate was 0.053% (n = 1477), 0.063% (n = 1765) and 0.069% (n = 1938) at 30, 60 and 90 days, respectively. Patients were readmitted to different hospitals 31% of the time within 90 days. Risk factors for different hospital VTE readmission were unique and included younger age and initial admission to a small/medium-sized hospital. Initial admission to a for-profit hospital increased the likelihood of readmission to a different hospital.

CONCLUSIONS

Nearly one in three postpartum VTEs are missed by the current quality metrics, with significant implications for outcomes and quality. For-profit hospitals have a significant portion of their VTE readmissions hidden, falsely lowering their readmission rates relative to public hospitals.

TWEETABLE ABSTRACT

US analysis shows 1 in 3 readmissions for postpartum venous thromboembolism currently missed.

Risk factors for postpartum readmission among women after having a stillbirth

BACKGROUND

Compared to women with a live birth, women with a stillbirth are more likely to have maternal complications during pregnancy and at birth, but risk factors related to their postpartum health are uncertain.

OBJECTIVE

This study aimed to identify patient-level risk factors for postpartum hospital readmission among women after having a stillbirth.

STUDY DESIGN

This was a population-based cohort study of 29,654 women with a stillbirth in California from 1997 to 2011. Using logistic regression models, we examined the association of maternal patient-level factors with postpartum readmission among women after a stillbirth within 6 weeks of hospital discharge and between 6 weeks and 9 months after delivery.

RESULTS

Within 6 weeks after a stillbirth, 642 women (2.2%) had a postpartum readmission. Risk factors for postpartum readmission after a stillbirth were severe maternal morbidity excluding transfusion (adjusted odds ratio, 3.02; 95% confidence interval, 2.28-4.00), transfusion at delivery but no other indication of severe maternal morbidity (adjusted odds ratio, 1.95; 95% confidence interval, 1.35-2.81), gestational hypertension or preeclampsia (adjusted odds ratio, 1.93; 95% confidence interval, 1.54-2.42), prepregnancy hypertension (adjusted odds ratio, 1.80; 95% confidence interval, 1.36-2.37), diabetes mellitus (adjusted odds ratio, 1.78; 95% confidence interval, 1.33-2.37), antenatal hospitalization (adjusted odds ratio, 1.78; 95% confidence interval, 1.43-2.21), cesarean delivery (adjusted odds ratio, 1.73; 95% confidence interval, 1.43-2.21), long length of stay in the hospital after delivery (>2 days for vaginal delivery and >4 days for cesarean delivery) (adjusted odds ratio, 1.59; 95% confidence interval, 1.33-1.89), non-Hispanic black race and ethnicity (adjusted odds ratio, 1.38; 95% confidence interval, 1.08-1.76), and having less than a high school education (adjusted odds ratio, 1.35; 95% confidence interval, 1.02-1.80). From 6 weeks to 9 months, 1169 women (3.90%) had a postpartum readmission; significantly associated risk factors were largely similar to those for earlier readmission.

CONCLUSION

Women with comorbidities, with birth-related complications, of non-Hispanic black race and ethnicity, or with less education had increased odds of postpartum readmission after having a stillbirth, highlighting the importance of continued care for these women after discharge from the hospital.

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

BACKGROUND

The American College of Obstetricians and Gynecologists suggests the initiation of postpartum antihypertensive treatment for women with hypertension in the postpartum period, a systolic blood pressure of ≥150 mm Hg or diastolic blood pressure of ≥100 mm Hg on 2 occasions at least 4 to 6 hours apart; however, the utility and validity of this strategy for preventing postpartum hypertension-related readmission remain unknown.

OBJECTIVE

The primary objective was to evaluate the accuracy of different blood pressure assessment strategies for predicting postpartum hypertension-related readmissions. The secondary objective was to consider the impact of using different blood pressure thresholds for initiating postpartum antihypertensive treatment vs the impact of using the current blood pressure threshold recommended by the American College of Obstetricians and Gynecologists.

STUDY DESIGN

A retrospective cohort study of 24,917 women who delivered at a single midwestern academic hospital between January 1, 2009, and June 30, 2015. Of those women, 3830 were identified as hypertensive, and 112 of 3830 women (2.92%) were readmitted for hypertension management. Blood pressures measured between delivery and 72 hours after delivery were used to evaluate 3 different blood pressure assessment strategies: average systolic or diastolic blood pressure exceeding the predetermined threshold (strategy 1), maximum systolic or diastolic blood pressure exceeding the predetermined threshold on 1 occasion (strategy 2), and maximum systolic or diastolic blood pressure exceeding the predetermined threshold on 2 occasions at least 4 hours apart (strategy 3). Analyzed blood pressure thresholds included all the integer blood pressure values between 100/50 mm Hg to 160/110 mm Hg for strategy 1 and 120/70 mm Hg to 190/140 mm Hg for strategies 2 and 3. The primary outcome was hypertension-related postpartum readmission. Receiver operating characteristic curves and the area under the curve were used to measure the predictive value of these strategies.

RESULTS

The American College of Obstetricians and Gynecologists' recommendation of using blood pressure ≥150/100 mm Hg as a threshold had a sensitivity of 38% and specificity of 95%, whereas following strategy 3 and reducing the threshold to 140/90 mm Hg demonstrated a sensitivity of 71% and specificity of 84%. The area under the curve for the 3 strategies were as follows: strategy 1 (area under the curve, 0.81; 95% confidence interval, 76.95-85.08), strategy 2 (area under the curve, 0.79; 95% confidence interval, 74.70-82.81), and strategy 3 (area under the curve, 0.83; 95% confidence interval, 79.83-87.24). The difference between the areas under the curve of strategies 2 and 3 was statistically significant (P<.0001).

CONCLUSION

The strategy of using the maximum systolic or diastolic blood pressure exceeding the blood pressure threshold on 2 occasions at least 4 hours apart at lower blood pressure thresholds can predict readmissions with higher sensitivity or specificity. Compared with the threshold of the American College of Obstetricians and Gynecologists' recommended blood pressure of ≥150/100 mm Hg, if the threshold for the postpartum antihypertensive treatment initiation was lowered to a blood pressure of ≥140/90 mm Hg, it would significantly reduce postpartum readmissions.

Pregnancy-related complications and risk of postpartum readmission for seizures and epilepsy: A national study

OBJECTIVE

Peripartum seizures remain a leading cause of maternal morbidity and mortality worldwide. Therefore, recognition of high-risk individuals is essential. We aimed to determine the rate and identify risk factors for postpartum seizure/epilepsy readmissions.

METHODS

In this retrospective cohort study, the Nationwide Readmissions Database was used to identify index admissions for delivery and readmissions for seizures in the year 2013, defined by International Classification of Disease, Ninth Revision, Clinical Modification codes for epilepsy, convulsions, and eclampsia in the primary diagnostic position. Logistic regression analysis was used to examine 30-day readmission for seizures as well as associations between demographic, medical, psychiatric, and pregnancy-related factors.

RESULTS

There were 1 633 714 index admissions for delivery, with a 30-day readmission rate for seizures/epilepsy of 19.69 per 100 000 index admissions. The mean age of index participants was 28.6 years (SD = 5.8). Postpartum 30-day readmissions for eclampsia represented 80% of seizure/epilepsy readmissions. Higher income was associated with lower odds of seizure/epilepsy readmission (odds ratio [OR] = 0.50, 95% confidence interval [CI] = 0.34-0.72, P = .03) for the highest income group. Eclampsia (OR = 19.9, 95% CI = 9.38-42.2, P < .001), preexisting epilepsy (OR = 10.63, 95% CI = 6.43-17.56, P < .001), pre-eclampsia (OR = 3.23, 95% CI = 2.31-4.51, P < .001), and gestational hypertension (OR = 2.78, 95% CI = 1.94-3.98, P < .001) were associated with readmission for seizures.

SIGNIFICANCE

Readmissions for seizures are fortunately rare, but are important to minimize given morbidity and mortality. Most seizure readmissions occurring within 30 days postpartum were coded as eclampsia rather than convulsions or pre-existing epilepsy. These findings suggest that early identification of women with pre-eclampsia and eclampsia may play a role in the prevention of postpartum seizures. Women with these risk factors should be identified to optimize care and monitored closely for seizure-associated complications.

Estimating the obstetric co-morbidity burden using administrative data: The impact of the pregnancy-related assessment window

BACKGROUND

Despite increased research using large administrative databases to identify determinants of maternal morbidity and mortality, the extent to which these databases capture obstetric co-morbidities is unknown.

OBJECTIVE

To evaluate the impact that the time window used to assess obstetric co-morbidities has on the completeness of ascertainment of those co-morbidities.

METHODS

We conducted a five-year analysis of inpatient hospitalisations of pregnant women from 2010-2014 using the Nationwide Readmissions Database. For each woman, using discharge diagnoses, we identified 24 conditions used to create the Obstetric Comorbidity Index. Using various assessment windows for capturing obstetric co-morbidities, including the delivery hospitalisation only and all weekly windows from 7 to 280 days, we calculated the frequency and rate of each co-morbidity and the degree of underascertainment of the co-morbidity. Under each scenario, and for each co-morbidity, we also calculated the all-cause, 30-day readmission rate.

RESULTS

There were over 3 million delivery hospitalisations from 2010 to 2014 included in this analysis. Compared with a full 280-day window, assessment of obstetric co-morbidities using only diagnoses made during the delivery hospitalisation would result in failing to identify over 35% of cases of chronic renal disease, 28.5% cases in which alcohol abuse was documented during pregnancy, and 23.1% of women with pulmonary hypertension. For seven other co-morbidities, at least 1 in 20 women with that condition would have been missed with exclusive reliance on the delivery hospitalisation for co-morbidity diagnoses. Not only would reliance on delivery hospitalisations have resulted in missed cases of co-morbidities, but for many conditions, estimates of readmission rates for women with obstetric co-morbidities would have been underestimated.

CONCLUSIONS

An increasing proportion of maternal and child health research is based on large administrative databases. This study provides data that facilitate the assessment of the degree to which important obstetric co-morbidities may be underascertained when using these databases.

Institutional prevalence of class III obesity modifies risk of adverse obstetrical outcomes

BACKGROUND

Women with prepregnancy class III obesity (body mass index ≥40 kg/m²) are at an increased risk of perinatal complications and adverse obstetrical outcomes. Estimates of the magnitude of risk that these women face vary widely, which may reflect differences in institutional experience caring for women with obesity.

OBJECTIVE

We sought to characterize the relationship between institutional prevalence of prepregnancy class III obesity and the risk of adverse perinatal outcomes among these women, hypothesizing that higher-prevalence institutions would have lower rates of adverse maternal and perinatal outcomes among this population.

STUDY DESIGN

We conducted a retrospective cohort study using chart-abstracted data on births in Washington state from Jan. 1, 2012, to Dec. 31, 2017. The analysis was restricted to hospitals that delivered at least 1 patient per month with prepregnancy class III obesity. Institutional prevalence of prepregnancy class III obesity was calculated, and hospitals were classified as either high or low prevalence. We included nulliparous women with vertex-presenting singleton pregnancies at ≥37 weeks of gestation. We excluded births with missing initial body mass index. The primary outcome was the incidence of cesarean delivery. Secondary outcomes were induction of labor, postpartum complications, postpartum readmission, and neonatal intensive care unit admissions. We compared outcomes between women with prepregnancy class III and all obesity at high- and low-prevalence hospitals using the χ² test or the Fishers exact test as appropriate. Binary logistic regression was performed to compare outcomes at high- and low-prevalence hospitals. A hospital-adjusted multivariable regression model that controlled for baseline institutional rates of each outcome and compared outcomes between high- and low-prevalence hospitals was developed. A final multivariable logistic regression that controlled for both baseline institutional variation as well as potential clinical confounders was performed.

RESULTS

A total of 20,556 women at 6 hospitals were eligible for inclusion; the prevalence of prepregnancy class III obesity was 6.2% and 2.1% in high- and low-prevalence hospitals, respectively. Obese women, including those with class III obesity in a high-prevalence hospital, were more likely to be Latina and less likely to be of advanced maternal age and carry private insurance. After adjusting for the institutional cesarean delivery rate, women with prepregnancy class III obesity had significantly increased odds of cesarean delivery (odds ratio, 1.53, 95% confidence interval, 1.12-2.10); however, after adjusting for significant covariates, the association no longer achieved significance (odds ratio, 1.68, 95% confidence interval, 0.97-2.94). The hospital-adjusted odds of postpartum readmission were significantly increased for women with prepregnancy class III obesity when delivering in low-prevalence institutions (odds ratio, 6.61, 95% confidence interval, 1.93-22.56), and the association was further strengthened after controlling for significant covariates (odds ratio, 15.20, 95% confidence interval, 2.32-99.53). None of the models demonstrated significantly different odds of induction of labor, postpartum complications, or neonatal intensive care unit admission by institutional prevalence of prepregnancy class III obesity.

CONCLUSION

Even after controlling for underlying hospital and subject characteristics, women with prepregnancy class III obesity had significantly increased odds of postpartum readmission, and a trend toward increased odds of cesarean delivery, when delivering in institutions with less experience caring for women with obesity.