New study looks at potential of measuring preventable severe maternal morbidity

March 2, 2023

Severe maternal morbidity (SMM) is defined as unexpected outcomes of labor and delivery that result in significant short- or long-term consequences to a person’s health, according to the Centers for Disease Control and Prevention (CDC). Healthcare organizations aim to improve maternal health outcomes and decrease SMM. While the CDC’s measure of SMM quantifies the prevalence of SMM, it is not restricted to potentially preventable SMM. As a result, the CDC SMM is not suitable for use as a quality indicator to compare hospitals or regions.

A new study in the March 2023 issue of The Joint Commission Journal on Quality and Patient Safety (JQPS) by Moshe Fridman, PhD and colleagues, proposes the use of performance SMM (pSMM), a modification of the CDC SMM, as a hospital performance measure. pSMM considers only those conditions that are hospital-acquired with a method for case-mix adjustment, thereby making it appropriate for comparison across hospitals. By definition, pSMM identifies SMM cases that are potentially responsive to quality improvement initiatives. The researchers defined pSMM using these three guidelines:

1.      Exclusion of preexisting conditions from outcomes

2.      Exclusion of inconsistently documented outcomes

3.      Risk adjustment for conditions that preceded hospitalization

To generate model-based expected pSMM values, the study classified California childbirth hospitals into four types: Community, Teaching, Integrated Delivery System (IDS) and IDS Teaching. Observed-to-expected (O/E) ratios were calculated for hospitals and used to categorize them as overperforming, average performing or underperforming. Performance categories were compared for pSMM vs. CDC SMM (excluding blood transfusion).

The overall rate of pSMM was 0.44%, which was less than half the previously published rate of CDC SMM (1.03%). Fewer than half of the observed cases of CDC SMM had the potential to be prevented through hospital practices, and therefore were attributable to hospital performance.

Higher rates of pSMM were observed in Teaching hospitals and IDS hospitals, compared to Community hospitals. The pSMM and CDC SMM also classified hospitals’ performance differently. The proportions of hospitals that changed performance categories when comparing pSMM to CDC SMM categorization were:

·        Community: 12.1%

·        Teaching: 25%

·        IDS: 38.9%

·        IDS Teaching: 66.7%

The researchers conclude that pSMM may be suitable for hospital comparisons because it identifies potentially preventable, hospital-acquired SMM that should respond to quality improvement activities.

“We have an opportunity to significantly improve a hospital-level SMM measure,” notes an accompanying editorial by Elliott K. Main, MD. “We should make our best effort at defining SMM but then focus on improving data quality and testing intervention efforts.”

The Joint Commission release

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