Relationship between Chronic Illness Care Quality and Current and Future Resource Use: An application of NCQA's HEDIS Relative Resource Use and Quality Measures

Objectives: The Relative Resource Use (RRU) measures developed by the National Commission on Quality Assurance are the first standardized measures that define efficiency of health plans. RRUs can be combined with measures of quality from the Healthcare Effectiveness Data and Information Set (HEDIS). RRUs measure total annual resource use using standard prices for cohorts of individuals who are in a HEDIS quality performance measure denominator population for several chronic condition categories. The research objective of this component of a larger study was to use RRU and HEDIS quality measures to determine the relationship between quality and cost for Medicare diabetes patients; and to determine whether prior quality performance predicts future resource use.

Design: Data sources for this study are: HEDIS comprehensive diabetes care measure set data submitted by Medicare managed care plans for reporting years 2007 and 2008 (based on 2006 and 2007 experience); RRU measures for reporting plans for year 2007 and 2008. The analysis focused on three quality indicators: the percentage of individuals with diabetes who had evidence of annual glycosyated hemoglobin (A1c) screening, low-density lipoprotein (LDL) screening, and retinal eye exams performed. RRU indicators included the total standard price per member per month. Plans were grouped into plan type (HMO etc). Pearson and Spearman rank correlations were calculated for quality and RRU measures to determine the stability of the relationships across the measures. A linear regression model was used to predict the relationship between quality in 2007 and resource use in 2008. All models controlled for percent of members with type 1 and type 2 diabetes co-morbidity, plan type, and region.

Population Studied: Adults ages 18 to 75 with diabetes enrolled in Medicare managed care plans. 141 plans reporting HEDIS quality measures and RRUs for both 2007 and 2008 which had no more than one missing quality or RRU variable were included.

Principal Findings: Overall, within year correlations among quality measures were strong ranging from 0.49 between LDL and eye exams to 0.72 between LCL and A1c. Increased A1c testing was associated with decreased inpatient care costs. As LDL screening increased, inpatient and pharmacy resource use decreased. Rates of eye exams in 2007 were not associated with resource use in 2008.

Conclusions: While higher quality in components of diabetes care seems to predict lower subsequent RRU, the broader relationship between quality of care and RRU remains complex, requiring a deeper understanding of the causal mechanisms involved.