Study Finds New Tool That Is Effective In Reducing Selection Bias In Comparative Effectiveness Research

Main Category: Public Health
Article Date: 22 Nov 2009 - 0:00 PST

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The study shows that stabilized weights can be used in observational studies to make valid comparisons between non-randomized treatment groups.

The new study, "Use of Stabilized Inverse Propensity Scores as Weights to Directly Estimate Relative Risk and Its Confidence Intervals", published in the journal, Value in Health, proposes the use of stabilized weights to obtain the treatment effect while reducing bias caused by patient selection.

The study demonstrated that the use of the stabilized weights produces appropriate estimation of the treatment effect and its precision (or variance) while keeping the false positive rate low (i.e. type I error rate =0.05).

Health care costs in the United States have been rising for several decades. To bend the curve, comparative effectiveness studies are essential to identify which health treatments work best for particular diseases or circumstances in the real world.

Now, a new study from Kaiser Permanente Colorado's Institute for Health Research has the potential to enhance the way comparative effectiveness research is performed. The findings come at a critical time: $1.1 billion from the federal government has been earmarked for this type of research and the first grants are now being awarded to investigators across the US.

Comparing different treatments in nonrandomized studies is complicated. Patients who receive particular treatments may be sicker or differ in other ways from patients not on those treatments. To draw valid conclusions, statistical and research tools must be used to improve the likelihood that similar patient populations are being compared.

"This approach is relatively easy to implement and can be used for different types of outcomes," said lead investigator Stanley Xu, PhD, a chief Biostatistician and investigator with Kaiser Permanente Colorado's Institute for Health Research.

Value in Health (ISSN 1098-3015) publishes papers, concepts, and ideas that advance the field of pharmacoeconomics and outcomes research and help health care leaders to make decisions that are solidly evidence-based. The journal is published bi-monthly and has a regular readership of over 4,000 clinicians, decision-makers, and researchers worldwide.

ISPOR is a nonprofit, international organization that strives to translate pharmacoeconomics and outcomes research into practice to ensure that society allocates scarce health care resources wisely, fairly, and efficiently.

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ISPOR