Validation of Postpartum Hemorrhage Admission Risk Factor Stratification in a Large Obstetrics Population

Abstract

Objective This study aimed to evaluate the performance of the California Maternal Quality Care Collaborative (CMQCC) admission risk criteria for stratifying postpartum hemorrhage risk in a large obstetrics population. Study Design Using detailed electronic health record data, we classified 261,964 delivery hospitalizations from Kaiser Permanente Northern California hospitals between 2010 and 2017 into high-, medium-, and low-risk groups based on CMQCC criteria. We used logistic regression to assess associations between CMQCC risk groups and postpartum hemorrhage using two different postpartum hemorrhage definitions, standard postpartum hemorrhage (blood loss ≥1,000 mL) and severe postpartum hemorrhage (based on transfusion, laboratory, and blood loss data). Among the low-risk group, we also evaluated associations between additional present-on-admission factors and severe postpartum hemorrhage. Results Using the standard definition, postpartum hemorrhage occurred in approximately 5% of hospitalizations (n = 13,479), with a rate of 3.2, 10.5, and 10.2% in the low-, medium-, and high-risk groups. Severe postpartum hemorrhage occurred in 824 hospitalizations (0.3%), with a rate of 0.2, 0.5, and 1.3% in the low-, medium-, and high-risk groups. For either definition, the odds of postpartum hemorrhage were significantly higher in medium- and high-risk groups compared with the low-risk group. Over 40% of postpartum hemorrhages occurred in hospitalizations that were classified as low risk. Among the low-risk group, risk factors including hypertension and diabetes were associated with higher odds of severe postpartum hemorrhage. Conclusion We found that the CMQCC admission risk assessment criteria stratified women by increasing rates of severe postpartum hemorrhage in our sample, which enables early preparation for many postpartum hemorrhages. However, the CMQCC risk factors missed a substantial proportion of postpartum hemorrhages. Efforts to improve postpartum hemorrhage risk assessment using present-on-admission risk factors should consider inclusion of other nonobstetrical factors.

Correlation between hemorrhage risk prediction score and severe maternal morbidity

“…14 Similar to previous work, we found that patients who were scored as medium or high risk for hemorrhage had significantly higher odds of receiving a transfusion compared with lowrisk patients. 14,16,23 Using the CDC criteria for SMM, transfusion has been documented as the most prevalent indicator for SMM. 4,18 As expected, transfusion was a driving factor for the association of hemorrhage risk score with SMM in our study.…”

“…We were unable to obtain specific data regarding the "history of postpartum hemorrhage," which is required to assign a medium-risk CMQCC score, because it cannot reliably be extracted from larger administrative databases with ICD-10 diagnosis codes. 16 Obstetrical hemorrhage was identified by ICD-10 diagnosis codes and was assigned at the discretion of individual providers at our institution. Our institution generally utilizes the American College of Obstetricians and Gynecologists' (ACOG) definition to diagnose clinically significant obstetrical hemorrhage.…”

Improving postpartum hemorrhage risk prediction using longitudinal electronic medical records

“…Assessments of the CMQCC have shown a statistically significant difference in risk for PPH between women in low-, medium-and high-risk groups. However, this same tool has consistently classified more than 40% of PPH cases as low-risk because they had no risk factors upon admission [18,21,22]. The tool underestimates risk for various definitions of severe PPH, as well as PPH defined as >1000mL cumulative blood loss.…”

“…Current risk stratification efforts for PPH have relied primarily on known risk factors (e.g., prior Cesarean delivery) [20]. While these factors are significant predictors of PPH, in many cases, PPH occurs in women with no known risk factors [11,18,21]. Considering this, we included both known risk factors and thousands of potential predictors extracted from EMR to maximize our ability to detect any patterns of clinical information that increase risk for PPH.…”

Prediction of postpartum hemorrhage in pregnant women with immune thrombocytopenia: Development and validation of the MONITOR model in a nationwide multicenter study

“…An important strategy to reduce PPH related adverse outcomes is routine assessment of PPH risk upon admission for delivery 16 . Limited tools have been previously developed to predict PPH risk.…”