Mortality Among Women with Sickle Cell Disease Admitted for Delivery, California 2004-2014

Maternal mortality results among women with sickle cell disease (SCD) from recent population-based studies using US hospital discharge data range from 72 (Villers, 2008) to 160 per 100,000 (Alayed, 2014). Researchers use hospital discharge or death certificate data to examine maternal death, as no national SCD surveillance system exists. We analyze California's surveillance data to describe the in-hospital maternal mortality rate among women meeting a stringent case definition for SCD, compare that rate to rates for all women and for Black women, and describe cases of SCD maternal demise.

The CDC has developed the Sickle Cell Data Collection (SCDC) program to conduct state level surveillance in this disease. SCDC uses a validated case definition: confirmed SCD with known genotype (via newborn screening or clinical case reports) or three or more healthcare encounters in administrative or claims data with SCD ICD-9 codes. California SCDC collected hospitalization data for years 2004-2014 on 1,829 women with SCD. We queried hospitalization data for women ages 15-45 at time of admission for ICD-9 codes for delivery (V27.X) with disposition codes indicating death during the same admission. We used the same query for all women and for Black women to calculate comparable in-hospital maternal mortality rates. We reviewed death records for ICD-10-CM underlying cause of death (COD) codes, and prior ED and inpatient records, and describe the history of the women with SCD who died.

We found 636 delivery hospitalizations among 441 of the 1,829 eligible women with SCD during the 11-year period. The maternal death rate for SCD was 629 per 100,000 (n = 4 of 636 deliveries), compared to 6 per 100,000 deliveries in the general population and 12 per 100,000 among Black women. There was an additional death (#5) among the women with SCD that occurred shortly after discharge; we include this death in the case descriptions, but not in the mortality rates. All of the women with SCD who died were Black. All births were live, singleton deliveries by cesarean surgery.

Case #1: 29 years old at death with no prior pregnancies in nine years of utilization data. She had a history of eight hospitalizations for septicemia, pneumonia and Hb SS with crisis, but none during her pregnancy. There were 16 ED visits, most related to SCD crisis and pain, but none in the prior three years. COD was 'O96.0, Death from direct obstetric cause.'

Case #2 was 34 years old and had seven prior years of medical history. She had no record of previous pregnancies, but had 44 prior hospital admissions and 95 ED encounters, including 12 in the year prior to her death. She had a history of venous thromboembolism, and deep phlebothrombosis was the primary diagnostic code for her final hospital admission. COD was 'D57.1 Sickle cell disease without crisis.'

Case #3 was 28, with four years of prior data. There was one previous cesarean birth 2.5 years prior to her death, and a record indicating that there were one or more prior cesarean deliveries before that. She had 11 prior ED encounters, most for pain, with one in the year prior to her death; there were 46 prior hospitalizations, most for SCD crisis. Primary diagnosis was severe pre-eclampsia. COD was 'D57.1 Sickle cell disease without crisis.'

Case #4 was 27, and had eight years of prior data and no prior births. She had 11 admissions, three in the months prior to her death for antepartum anemia. There were 12 prior ED encounters, three for antepartum anemia. Her death included codes for heart, liver, kidney and respiratory failure after delivery. COD was 'O96.0,' as described in Case #1. She died 11 days after delivery.

Case #5 was 20, and had five years of utilization data with no prior births. Her labor was induced due to fetal distress, and she was hospitalized for six days. Records included a code for infection of the amniotic cavity. Four days after release, she was re-admitted for puerperal sepsis, suffered multi-organ failure, and died. There were 10 prior ED encounters, including four during and related to the pregnancy. COD was 'O23.5, Infections of the genital tract in pregnancy.'

We found maternal mortality among women with SCD to be significantly higher than previous estimates. Statewide surveillance based on multiple data sources, and that follows individual patients over time whether or not they are seen in sickle cell disease clinics, can provide less biased information on health outcomes than analyses of single data sources or clinical sites.