Evaluating the Impact of the Venous Thromboembolism Outcome Measure on the PSI 90 Composite Quality Metric

Patient Safety Indicator (PSI) 90 is a composite measure widely used in federal pay-for-performance and public reporting programs. A component metric of PSI 90, venous thromboembolism (VTE) rate, has been shown to be subject to surveillance bias and not a valid measure for hospital quality comparisons. A study was conducted to examine how hospital PSI 90 scores would change if the VTE measure were removed from calculation of this composite measure.

Using 2014 Medicare inpatient claims data, PSI 90 scores were calculated with and without the VTE measure for 3,203 hospitals. Hospital characteristics obtained from the American Hospital Association Annual Survey and Centers for Medicare & Medicaid Services Payment Update Impact File were merged with PSI 90 scores.

Removing the VTE outcome measure from the calculation of PSI 90 version 5 improved PSI 90 scores for 17.1% of hospitals but lowered scores for 20.8% of hospitals, while 62.1% had no change in scores. Hospitals were more likely to improve on PSI 90 when the VTE measure was removed if they were larger (odds ratio [OR] = 1.60; 95% confidence interval [CI] = 1.00-2.58), were major teaching hospitals (OR = 1.76; 95% CI = 1.10-2.79), had greater technological resources (OR = 2.03; 95% CI = 1.40-2.94), or cared for sicker patients (OR = 1.12; 95% CI = 1.01-1.25).

Inclusion of the surveillance bias-prone VTE outcome measure in the PSI 90 composite disproportionately penalizes larger, academic hospitals and those that care for sicker patients. Removal of the VTE outcome measure from PSI 90 should be strongly considered.