Predicted quality-adjusted life years as a composite measure of the clinical value of diabetes risk factor control.

BACKGROUND

Control of blood pressure, low-density lipoprotein cholesterol (LDL-c), and A1c can lower the risk for diabetes complications. These quality indicators often are examined separately and weighted equally in performance measurement, potentially discarding important information.

OBJECTIVES

We sought to create a composite indicator of the clinical benefit, or value, of diabetes risk factor control that appropriately weights the clinical importance of A1c, LDL-c, and blood pressure, and to test its usability for quality measurement.

METHODS

The combined value of control for 3 diabetes risk factors, measured by predicted quality-adjusted life years (QALYs), was compared in diabetes patients (n = 129,236 in 2001; n = 185,006 in 2003) in Kaiser Permanente Northern California across 16 medical center populations in 2001 and 2003 using hierarchical linear regression to adjust for case-mix differences. Patient-level QALYs, simulated from risk factor and case-mix variables in a Markov model, was the main outcome variable.

RESULTS

There was significant cross-sectional variability in average case-mix adjusted QALYs for diabetes patients across centers in 2003. QALYs increased from 2001 to 2003 as the result of improved risk factor control; longitudinal improvements in QALYs also showed variation across centers. Regression analyses demonstrated the greater impact of blood pressure versus LDL-c or A1c control on QALYs, and the greater value of risk factor control in those with poor versus near or in-control blood pressure.

CONCLUSION

Using predicted QALYs to measure value holds promise as a sensitive composite indicator for quality measurement. Complex, evidence-based quality indicators such as these can potentially provide accurate and useful information to health plans, providers, and consumers.