Table 2.

Studies examining the impact of benefit caps on prescription drug utilization and spending, medical utilization and spending (11 studies)

Author	Study sample	Study design	Drug benefit variation	Outcomes	Key findings
Studies that examine the impact on prescription drug utilization only
Tseng CW et al., 2004	1,308 Medicare managed care enrollees in 2001 whose drug benefits were capped and annual spending exceeded annual caps of $750 or $1,200 (Survey data 2002)	Cross-sectional	Variations in annual drug benefit caps across counties	Under-use due to cost Rx switching	Medicare + Choice beneficiaries exceeding their annual drug benefit cap were more likely than those that did not exceed the cap to switch medications (15% vs. 9%), use samples (34% vs. 27%) and report difficulty paying for prescriptions (62% vs. 37%).
Tseng CW et al., 2003	438,802 Medicare managed care enrollees in 2001 whose drug benefits were capped at $750, $1,000 or $2,000. (Pharmacy claims data 2001)	Cross-sectional	Levels of annual drug benefit caps: $750, $1,000, or $2,000.	% exceeding benefit caps OOP Rx spending	A total of 22%, 14%, and 4% of Medicare patients exceeded annual drug benefit caps of $750, $1,000, and $2,000, respectively.
Cox ER et al., 2002	212 Medicare+Choice beneficiaries with capped annual prescription drug benefits of $500 or $1,000 in year 2000 (Survey data)	Cross-sectional	Capped drug benefits	Adherence Discontinuation	For those who exceeded their cap prior to Oct 2000, they were more likely to stop taking one or more medications or took less than prescribed amount, after reaching the cap, compared to the pre-cap period. But these differences were not statistically significant.
Balkrishnan R et al., 2001	259 Medicare HMO enrollees in 1997–1998 (Data source unknown)	Before-after no control group	Change of drug benefit policy from 1997–1998: benefit cap increased from $500 per year to $200 per quarter; and co-payments changed from $6/$12 to $7/$15, for generics and brand names, separately	Plan Rx spending Plan Rx + medical spending	Drug benefit cap from $500 per year to $200 per quarter and increased drug co-payments were associated with a 29% increase in plan Rx costs and 38% increase in total plan costs.
Cox ER et al., 2001	378 Medicare HMO enrollees who had reached >=60% of their prescription drug cap in 1997 (Survey data)	Cross-sectional	Capped drug benefits ($750 for rural counties, $1,500 for urban counties)	Initiation of drug therapy Adherence/compliance/MPR Rx switching	Those who reached their prescription cap were more likely to reduce drug use (OR, 2.83), to discontinue a medication (OR, 3.36), and to obtain samples from their physician (OR, 2.02), compared to those who had not reached their cap.
Fortess EE et al., 2001	343 chronically ill Medicaid enrollees (Pharmacy claims data)	Before-after no control group	A state Medicaid program imposed a three-prescription monthly reimbursement limit(12 months pre- and 6 months after policy change)	Standard monthly doses for essential medications	A three-prescription monthly reimbursement limit (cap) in the New Hampshire Medicaid program was associated with a 34.4% reduction in the use of essential medications.
Martin BC et al., 1996	743 Medicaid enrollees (Pharmacy claims data 1991–1992)	Time series	A state Medicaid program reduced monthly reimbursement limit of prescriptions from six to five (6 months pre- and 6 months after policy change)	Number of filled prescriptions Rx spending OOP and plan Rx spending	Reducing the maximum number of monthly reimbursable prescriptions from 6 to 5 was associated with a 6.6% reduction in total prescriptions among Georgia Medicaid beneficiaries with high use of prescription drugs.
Soumerai SB et al., 1987	10,734 Medicaid enrollees (Pharmacy claims data 1980–1983)	Time series	New Hampshire Medicaid program imposed a three-prescription monthly reimbursement limit (cap) on Sep 1981, but later discontinued the policy (20 months pre-policy change; 11 months post-policy change; 17 months after the limit was replaced by $1 co-payment).	Number of filled prescriptions	A three-prescription monthly reimbursement limit (cap) in the New Hampshire Medicaid program was associated with a 30% reduction in the number of prescriptions filled. Utilization approached pre-cap levels after the cap was replaced with a $1 co-payment.
Studies that also examine the impact on medical utilization and spending
Hsu et al., 2006	199,179 Medicare managed care enrollees in 2003 (Administrative data 2003)	Cross-sectional	In 2003, 157,275 Medicare + Choice enrollees had annual drug benefit capped at $1,000; Another 41,904 enrollees had unlimited drug coverage due to employee supplements	Adherence Rx and medical spending Hospitalizations, ED visits, and ambulatory visits Blood pressure, LDL, Glycated hemoglobin, and mortality	Subjects facing a $1,000 Rx benefit cap had 31% lower pharmacy costs, higher rates of drug non-adherence (Odd ratios of 1.27 to 1.33), ED visits (RR 1.09), non-elective hospitalizations (RR 1.13), and death (RR 1.22). Their total medical costs were not significantly different from those without Rx benefit cap.
Soumerai SB et al., 1994	2,227 Medicaid enrollees with Schizophrenia (Pharmacy and medical claims data 1980–1983)	Time series	New Hampshire Medicaid program imposed a three-prescription monthly reimbursement limit (cap) on Sep 1981, but later discontinued the policy (14 months pre-policy change; 11 months post-policy change; 17 months after the limit was replaced by $1 co-payment).	Days of supply Plan Rx spending Plan medical spending Ambulatory visits Hospitalizations	A three-prescription monthly reimbursement limit (cap) in the New Hampshire Medicaid program was associated with an immediate reduction (ranged 15% to 49%) in the use of psychotropic drugs, a significant increase in the use of emergency mental health services and partial hospitalization, but not associated with hospital admissions. Drug and medical utilizations approached pre-cap levels after the cap was replaced with $1 co-payment.
Soumerai SB et al., 1991	1,786 Medicaid enrollees who in a baseline year had been taken 3 or more prescriptions per month (Pharmacy and medical claims data 1980–1983)	Time series	New Hampshire Medicaid program imposed a three-prescription monthly reimbursement limit (cap) on Sep 1981, but later discontinued the policy.	Days of supply Nursing home admissions Hospitalizations	A three-prescription monthly reimbursement limit (cap) in the New Hampshire Medicaid program was associated with a 35% reduction of drug utilizations, increased risk of nursing home admissions, but not with hospitalizations, among older patients (60 and older) and who were frequent Rx users.