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.

INTRODUCTION: Venous thromboembolism (VTE) causes morbidity and mortality after delivery and is a quality indicator. Prior studies have found that readmission to a different hospital can be significant and hidden, with unique risk factors. The national rate of postpartum different hospital readmission for VTE is unknown. The purpose of this study was to calculate the rate of missed postpartum VTE. METHODS: The 2014 Nationwide Readmissions Database was queried for patients >14 years with a delivery hospitalization. Outcomes included: 30-, 60-, and 90-day readmission with VTE to index and different hospitals. Multivariate logistic regression identified risk factors. RESULTS: Of the 3,718,711 patients queried, VTE readmission rate was 0.046% (n=1,729), 0.053% (n=1,972), and 0.055% (n=2,047) at 30-, 60-, and 90-days, respectively. Patients were readmitted to different hospitals 27.13%, 29.01%, and 29.70% of the time at 30-, 60-, and 90-days, respectively. Risk factors for different hospital readmission for VTE at 60-days were unique compared to index hospital VTE readmission risk factors and included initial admission to a for-profit hospital (OR 1.80 [1.33-2.42], p<0.01) and Medicaid (OR 1.33 [1.06-1.66], p=0.01). Initial admission to a public hospital decreased the likelihood of different hospital readmission for VTE (OR 0.69 [0.49-0.97], p=0.04). CONCLUSION: Nearly one in three postpartum VTEs are missed by current quality metrics, with significant implications for outcomes and quality. For-profit hospitals have more VTE readmissions hidden, falsely lowering their readmission rates relative to public hospitals. Women who are publicly insured are at higher risk for disruption of their continuity of care.