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Open Access Publications from the University of California

The University of California, Davis Center for Health Services Research in Primary Care provides research and evaluation services relating to primary care medicine and its organization, cost, quality and effect upon patient outcomes.

Since its founding in 1994, the Center has conducted numerous studies addressing public health policy. Our emphasis on primary care reflects the central role primary care plays in our health care system today.

Cover page of Outcomes for Maternal Hospital Care in California, 1999-2001

Outcomes for Maternal Hospital Care in California, 1999-2001

(2008)

The California Hospital Outcomes Program is an initiative mandated by the State of California, and conducted by the Office of Statewide Health Planning and Development (OSHPD), to develop public reports comparing hospital outcomes for selected conditions and treatments in hospitals throughout the state. Over the last decade, OSHPD has reported hospital mortality rates for heart attack and community-acquired pneumonia. A separate OSHPD program produces reports on hospital and surgeon outcomes for heart bypass surgery (www.oshpd.ca.gov).

This is the first public report that OSHPD has published on maternal hospital care in California. The report is based on analysis of Patient Discharge Data (PDD) records submitted to OSHPD by licensed acute care hospitals, as well as Vital Statistics (VS) birth certificate records submitted to the California Department of Public Health. The delivery patients were admitted to the hospital between October 1999 and November 2001.

The quality of hospital performance for maternity care was assessed by estimating each hospital’s rate of two undesirable outcomes: severe perineal lacerations (tears) and postpartum maternal readmissions. Severe perineal lacerations, also described as 3rd or 4th degree, are common but often painful complications of vaginal births. Postpartum maternal readmissions reflect rare but serious complications that occur within 6 weeks after delivery, and require that a woman be readmitted to receive intravenous fluids, powerful antibiotics, surgery, or close monitoring. Both of these quality indicators were risk-adjusted to account for differences in patients’ underlying risk of these undesirable outcomes. Each hospital’s risk-adjusted rate was then compared with the statewide average, which serves as a benchmark. Hospitals are defined as “better” if their risk-adjusted laceration or readmission rates were statistically significantly lower than the state rate and “worse” if their rates were higher.

To provide more information for women and their families, this report also shows each hospital’s vaginal or cesarean delivery rate for two important groups of women: low-risk women who are admitted for their first deliveries, and high-risk women who have had at least one prior cesarean delivery. We focus on these two groups of women because their risk of cesarean delivery is particularly high, and because that risk varies widely across hospitals. By contrast, women who have had prior vaginal deliveries, and no prior cesarean deliveries, tend to have a very low risk of cesarean delivery with subsequent pregnancies, no matter where they go for hospital care. Women with other high risk factors, such as having babies that present feet-first (footling breech) or buttocks-first (breech) instead of head-first, tend to have a very high risk of cesarean delivery no matter where they go.

Key findings from this report include:

• During the study period, 860,588 eligible women were admitted to acute care, nonfederal hospitals in California for delivery of a live baby. Of these women, 4,029 (0.47%) were readmitted to any hospital within 6 weeks after delivery because of a postpartum complication.

• Across the 301 eligible hospitals, the number of eligible deliveries during the study period ranged from 1 to 12,811, and the number of readmissions ranged from 0 to 89. The risk-adjusted readmission rate was 0% for 17 hospitals, 0.01% to 0.49% for 159 hospitals, 0.5% to 0.99% for 110 hospitals, 1.0% to 1.49% for 10 hospitals, and 1.5% or greater for 5 hospitals.

• Sixteen hospitals had significantly fewer readmissions than were expected, based on the characteristics of their patients, whereas fourteen hospitals had significantly more readmissions than were expected.

• During the study period, 651,640 eligible women were admitted to acute care nonfederal hospitals in California and underwent an eligible vaginal delivery. Of these women, 31,331 (4.81%) experienced a third or fourth degree tear.

• Across the 301 eligible hospitals, the number of eligible vaginal deliveries during the study period ranged from 1 to 9,815, and the number of third or fourth degree tears ranged from 0 to 597. The risk-adjusted laceration rate was less than 5% for 180 hospitals, 5% to 10% for 110 hospitals, 10% to 15% for 8 hospitals, and 15% or greater for 3 hospitals.

• Seventy-three hospitals had significantly fewer lacerations than were expected, based on the characteristics of their patients, whereas fifty-six hospitals had significantly more lacerations than were expected.

• There was a weak but consistent association between the risk-adjusted readmission rate (among all deliveries) and the risk-adjusted laceration rate (among vaginal deliveries) at the hospital level. For example, 8 of the 14 hospitals rated as “worse than expected” for postpartum readmissions were also rated as “worse than expected” for tears. Similarly, 8 of the 16 hospitals rated as “better than expected” for postpartum readmissions were also rated as “better than expected” for tears. The concordance between these indicators at the hospital level was surprisingly strong.

• It is critical that all hospitals providing maternal care implement the “best practice” guidelines supported by the medical community. OSHPD’s Postpartum Maternal Outcomes Validation Study suggested that many postpartum readmissions could be prevented through careful evaluation of every patient before discharge and prompt attention to early signs of infection. Other clinical and epidemiological studies (summarized below) have suggested that many perineal tears could be prevented by minimizing use of forceps and episiotomy and avoiding certain positions during labor.

• Coding problems do not appear to cause substantial bias in these analyses, but still need to be addressed by California hospitals. For example, about 0.3% of vaginal delivery records and 0.5% of cesarean delivery records had prohibited combinations of 5th digit ICD-9-CM codes, leading to confusion about whether the affected records were antepartum, childbirth, or postpartum records.

Cover page of OSHPD Postpartum Maternal Outcomes Validation Study

OSHPD Postpartum Maternal Outcomes Validation Study

(2006)

The California Hospital Outcomes Project is an initiative mandated by the State of California and conducted by the Office of Statewide Health Planning and Development (OSHPD), to develop public reports comparing hospital outcomes for selected medical conditions and surgical procedures for patients treated in hospitals throughout California. Over the last decade, CHOP has reported risk-adjusted hospital mortality rates for heart attack and community-acquired pneumonia. In 2005, OSHPD is releasing its first report on obstetric care.

Delivery was selected as an important topic for public reporting because it is the most frequent single reason for hospitalization in California, and because complications of delivery are associated with substantial health care costs and impairment of function. In 2003, for example, there were 170,465 repairs of obstetric lacerations and 147,084 cesarean deliveries performed in California hospitals – more than any other surgical procedure. Although most women who require these procedures have excellent outcomes, a small minority experience complications that cause pain, weakness, impaired bonding with their new child, bowel or bladder problems, sexual dysfunction, rehospitalization, and even death.

This technical report, prepared for OSHPD, summarizes the validation of multiple potential measures of inpatient obstetric quality of care. These measures include two that have been endorsed by OSHPD for public reporting: risk-adjusted postpartum maternal readmission rates and risk-adjusted perineal laceration rates. Other measures were also evaluated in this validation study, but are not recommended for public reporting, including risk-adjusted rates of endometritis, wound infection, hemorrhage, and urinary tract infection. This validation study was designed by the UC Davis research team in collaboration with OSHPD staff and the AB 524 Technical Advisory Committee. It was designed to address a variety of concerns, specified in detail later in this report, about the validity of using hospital-reported ICD-9-CM codes in the California Patient Discharge Data Set to report publicly on hospital performance.

The original methodology for estimating and analyzing risk-adjusted postpartum maternal readmission rates was developed in 1996, using data on deliveries performed in 1992-1993. This developmental work is fully described in a report that was published by the OSHPD in December 1996 (Section 2, citation 19). We were subsequently asked by the OSHPD to validate the data and methodology used in this 1996 report. To simplify the task, we selected a subsample of the same records for this validation study. As described in detail in later sections of this report, we collected records from hospitals in 1998, recoded and abstracted them in 1999, and performed analyses in 2000-2001. Although some results from these analyses have already appeared in print elsewhere, this report compiles all relevant findings in a single document. We believe that the findings are still informative, despite their age, because there is no evidence of statewide improvement in the coding of obstetric records over the past decade. In addition, the mean postpartum length of stay and readmission rate have remained relatively stable over time (after some decrease in length of stay during the 1990s), suggesting that the clinical factors driving readmissions have also been relatively stable. This study remains the most comprehensive published analysis of the accuracy of ICD-9-CM coded inpatient obstetric data. However, if the OSHPD continues to use the same datasets in the same manner, it would be prudent to repeat this validation study in the future.