Including stroke severity in risk models improves mortality prediction

July 20, 2012 By Keith Herrell

(Medical Xpress) -- Adding stroke severity to a hospital 30-day mortality model based on claims data for Medicare beneficiaries with acute ischemic stroke was associated with improvement in predicting the risk of death at 30 days and changes in performance ranking regarding mortality for a considerable proportion of hospitals, according to a new study whose authors include two University of Cincinnati (UC) neurologists.

The study is published in the July 18, 2012, issue of JAMA: The . Authors include Joseph Broderick, MD, Albert Barnes Voorheis Chair and professor of neurology at UC, and Dawn Kleindorfer, MD, professor and division director of cerebrovascular disease at UC. Both are members of the UC Neuroscience Institute. The study was led by Gregg Fonarow, MD, of the University of California, Los Angeles.

Background information in the article notes that "increasing attention has been given to defining the quality and value of health care through reporting of process and outcome measures,” including 30-day mortality rates. Stroke, the authors add, is among the leading causes of death, disability, hospitalizations and health care expenditures in the United States.

The researchers conducted a study to evaluate the degree to which hospital outcome ratings and the ability to predict 30-day mortality are altered after including initial stroke severity in a claims-based risk model for hospital 30-day mortality for . For the study, data were analyzed from 782 Get With The Guidelines–Stroke participating hospitals from April 2003 to December 2009 on 127,950 fee-for-service with .

The patients had a score documented for the National Institutes of Health Stroke Scale (NIHSS), a 15-item neurological examination scale developed at UC in the 1980s with scores from 0 to 42 (higher scores indicate more severe strokes). The median (midpoint) age was 80 years, 57 percent were women, and 86 percent were white. Performance of claims-based hospital mortality risk models with and without inclusion of NIHSS scores for 30-day mortality was evaluated and hospital rankings from both models were compared.
 
There were 18,186 deaths (14.5 percent) within the first 30 days, including 7,430 deaths during the index hospitalization (in-hospital mortality, 5.8 percent). The median hospital-level 30-day mortality rate was 14.5 percent. The researchers found that the hospital mortality model with NIHSS scores had significantly better discrimination than the model without. Also, other index scores demonstrated substantially more accurate classification of hospital 30-day mortality after the addition of NIHSS score to the claims model. The model with NIHSS exhibited better agreement between observed and predicted mortality rates.

Analysis of data indicated that more than 40 percent of hospitals identified in the top or bottom 5 percent of hospital risk-adjusted mortality would have been reclassified into the middle mortality range using a model adjusting for NIHSS score compared with a model without NIHSS score adjustment. "Similarly, when considering the top 20 percent and bottom 20 percent ranked hospitals, close to one-third of hospitals would have been reclassified,” the authors write.

"Inclusion of a validated measure of stroke severity is critical for any model of mortality after stroke,” says Broderick. "Government and private health insurers who are moving toward public reporting of hospital-based mortality rates and value-based purchasing must include measures of stroke severity in their models to provide accurate comparisons of between hospitals.”

Adds Kleindorfer: "Health care systems that treat stroke patients must work to ensure that stroke severity is consistently measured and recorded on all hospitalized stroke patients. This currently doesn’t occur at most hospitals, yet we know that how bad a stroke is when you come to the hospital is the most important predictor of outcome later on. Without knowing this information, hospitals will not be fairly judged regarding the quality of care they provide.” 

The Get With the Guidelines–Stroke program is provided by the AHA/American Stroke Association. The program is supported in part by a charitable contribution from Janssen Pharmaceuticals Inc., a pharmaceutical company of Johnson & Johnson. Neither Broderick nor Kleindorfer report receiving funding from Janssen Pharmaceuticals, Inc.

In an accompanying editorial, Tobias Kurth, MD, of the University of Bordeaux, France, and Mitchell S.V. Elkind, MD, of Columbia University write that the study’s results "clearly highlight the importance of incorporating information on stroke severity when conducting health outcomes research in stroke.”

"The particular characteristics of stroke have to be taken into consideration by clinicians, insurance companies, and policy makers when comparing disease-specific health outcomes.”

Explore further: Hospitals' stroke-care rankings change markedly when stroke severity is considered

Related Stories

Hospitals' stroke-care rankings change markedly when stroke severity is considered

July 17, 2012
As part of the Affordable Care Act, hospitals and medical centers are required to report their quality-of-care and risk-standardized outcomes for stroke and other common medical conditions. But reporting models for mortality ...

Study suggests poorer outcomes for patients with stroke hospitalized on weekends

July 9, 2012
A study of patients with stroke admitted to English National Health Service public hospitals suggests that patients who were hospitalized on weekends were less likely to receive urgent treatments and had worse outcomes, according ...

Treatment for minority stroke patients improves at top-ranked hospitals

June 21, 2011
After years of research have shown that minorities do not receive the same quality of health care as whites do, a new study suggests there has been some improvement in reducing the gap, at least for stroke patients.

Recommended for you

Amber-tinted glasses may provide relief for insomnia

December 15, 2017
How do you unwind before bedtime? If your answer involves Facebook and Netflix, you are actively reducing your chance of a good night's sleep. And you are not alone: 90 percent of Americans use light-emitting electronic devices, ...

Warning labels can help reduce soda consumption and obesity, new study suggests

December 15, 2017
Labels that warn people about the risks of drinking soda and other sugar-sweetened beverages can lower obesity and overweight prevalence, suggests a new Johns Hopkins Bloomberg School of Public Health study.

Office work can be a pain in the neck

December 15, 2017
Neck pain is a common condition among office workers, but regular workplace exercises can prevent and reduce it, a University of Queensland study has found.

Regular takeaways linked to kids' heart disease and diabetes risk factors

December 14, 2017
Kids who regularly eat take-away meals may be boosting their risk factors for heart disease and diabetes, suggests research published online in the Archives of Disease in Childhood.

Simulation model finds Cure Violence program and targeted policing curb urban violence

December 14, 2017
When communities and police work together to deter urban violence, they can achieve better outcomes with fewer resources than when each works in isolation, a simulation model created by researchers at the UC Davis Violence ...

One in five patients report discrimination in health care

December 14, 2017
Almost one in five older patients with a chronic disease reported experiencing health care discrimination of one type or another in a large national survey that asked about their daily experiences of discrimination between ...

0 comments

Please sign in to add a comment. Registration is free, and takes less than a minute. Read more

Click here to reset your password.
Sign in to get notified via email when new comments are made.