ACE Inhibitor and ARB utilization and expenditures in the Medicaid fee-for-service program from 1991 to 2008

Angiotensin-converting enzyme (ACE) inhibitors and angiotensin receptor blockers (ARBs) are widely prescribed for the treatment of hypertension and heart failure, as well as for kidney disease prevention in patients with diabetes mellitus and the management of patients after myocardial infarction.

To (a) describe ACE inhibitor and ARB utilization and spending in the Medicaid fee-for-service program from 1991 through 2008, and (b) estimate the potential cost savings for the collective Medicaid programs from a higher ratio of generic ACE inhibitor utilization.

A retrospective, descriptive analysis was performed using the National Summary Files from the Medicaid State Drug Utilization Data, which are composed of pharmacy claims that are subject to federally mandated rebates from pharmaceutical manufacturers. For the years 1991-2008, quarterly claim counts and expenditures were calculated by summing data for individual ACE inhibitors and ARBs. Quarterly per-claim expenditure as a proxy for drug price was computed for all brand and generic drugs. Market shares were calculated based on the number of pharmacy claims and Medicaid expenditures.

In the Medicaid fee-for-service program, ACE inhibitors accounted for 100% of the claims in the combined market for ACE inhibitors and ARBs in 1991, 80.6% in 2000, and 64.7% in 2008. The Medicaid expenditure per ACE inhibitor claim dropped from $37.24 in 1991 to $24.03 in 2008 when generics accounted for 92.5% of ACE inhibitor claims; after adjusting for inflation for the period from 1991 to 2008, the real price drop was 59.2%. Brand ACE inhibitors accounted for only 7.5% of the claims in 2008 for all ACE inhibitors but 32.1% of spending; excluding the effects of manufacturer rebates, Medicaid spending would have been reduced by $28.7 million (9%) in 2008 if all ACE inhibitor claims were generic. The average price per ACE inhibitor claim in 2008 was $24.03 ($17.64 per generic claim vs. $103.45 per brand claim) versus $81.98 per ARB claim. If the ACE inhibitor ratio had been 75% in 2008 rather than 64.7%, the Medicaid program would have saved approximately 13% or about $41.8 million, again excluding the effects of manufacturer rebates. If the ACE inhibitor ratio had been 90% in 2008, the cost savings for the combined Medicaid fee-forservice programs would have been about 33% or about $102.3 million. The total cost savings opportunity with 100% generic ACE inhibitor utilization in 2008 and an ACE inhibitor ratio of 75% was $75.1 million (24%) or $142.3M (46%) with a 90% ACE inhibitor ratio.

Factors that affect Medicaid spending by contributing to increased utilization of ACE inhibitors and ARBs, such as the rising prevalence of hypertension, heart disease, and diabetes, can be offset by reduction in the average price attained through a higher proportion of ACE inhibitors and a higher percentage of generic versus brand ACE inhibitors.