Variation in prescription use and spending for lipid-lowering and diabetes medications in the Veterans Affairs Healthcare System

Abstract

Objectives: To examine variation in outpatient prescription use and spending for hyperlipidemia and diabetes mellitus in the Veterans Affairs Healthcare System (VA) and its association with quality measures for these conditions.

Study design: Cross-sectional.

Methods: We compared outpatient prescription use, spending, and quality of care across 135 VA medical centers (VAMCs) in fiscal year 2008, including 2.3 million patients dispensed lipid-lowering medications and 981,031 patients dispensed diabetes medications. At each facility, we calculated VAMC-level cost per patient for these medications, the proportion of patients taking brand-name drugs, and Healthcare Effectiveness Data and Information Set (HEDIS) scores for hyperlipidemia (low-density lipoprotein cholesterol level <100 mg/dL) and for diabetes (glycosylated hemoglobin level >9% or not measured).

Results: The median cost per patient for lipid-lowering agents in fiscal year 2008 was $49.60 and varied from $39.68 in the least expensive quartile of VAMCs to $69.57 in the most expensive quartile (P < .001). For diabetes agents, the median cost per patient was $158.34 and varied from $123.34 in the least expensive quartile to $198.31 in the most expensive quartile (P < .001). The proportion of patients dispensed brand-name oral drugs among these classes in the most expensive quartile of VAMCs was twice that in the least expensive quartile (P < .001). There was no correlation between VAMC-level prescription spending and performance on HEDIS measures for lipid-lowering drugs (r = 0.12 and r = 0.07) or for diabetes agents (r = -0.10).

Conclusions: Despite the existence of a closely managed formulary, significant variation in prescription spending and use of brand-name drugs exists in the VA. Although we could not explicitly risk-adjust, there appears to be no relationship between prescription spending and quality of care.

Figure 1

Relationship between cost/patient for lipid-lowering and diabetes agents. Each data point represents one VAMC (r=0.41, p <.001).

Figure 2

The cost/patient for lipid-lowering (top) and diabetes (bottom) agents for FY 2008 in VAMCs and HEDIS quality of care measurements at each facility. Each dot represents one VAMC. For lipid-lowering agents, two separate HEDIS measures are included, represented by different shaded dots

Figure 3

The cost/patient for lipid-lowering (top) and diabetes (bottom) agents for FY 2008 in VAMCs and HEDIS quality of care measurements at each facility, limited to facilities rated as complexity level 1a or 1b (high complexity).