Self-reported Effects of Prescription Drug Cost-Sharing: Decreased Adherence and Increased Financial Burden Mary Reed, MPH 1 Vicki Fung 1 Richard Brand, PhD 2 Bruce Fireman, MA 1 Joseph P. Newhouse, PhD 3 Joseph V. Selby, MD, MPH 1 John Hsu, MD, MBA, MSCE 1 1 Kaiser Permanente - Division of Research 2 University of California, San Francisco 3 Harvard University Academy Health Annual Research MeetingJune 7, 2004

Introduction ► Drug expenditures are increasing each year in the US ► Patients are paying for an increasing share for their prescription drugs: cost-sharing ► Cost-sharing effects may be influenced by patient knowledge ► Limited information about: –Patient knowledge about their prescription drug cost-sharing –How patients behave when faced with this cost-sharing

Purpose ► To examine patient knowledge of their prescription drug cost-sharing level: –Any prescription drug cost-sharing? –Structure of prescription drug cost-sharing (multi-tier copayments and benefit caps)? –Amount of drug cost-sharing (copayment amounts and benefit cap amounts)? ► To examine self-reported patient behavioral responses to prescription drug cost-sharing: –Do patients report taking less than the prescribed amount of a drug (adherence)? –Do patients report having to struggle to pay for their prescription drugs (burden)?

Methods – Design/Population/Sample ► Cross-sectional Design: Telephone interviews in 2003 ► Population: –Active members in a large, prepaid integrated delivery system (IDS) –Age 18 years or more –English-speaking –Commercial or Medicare insurance ► Stratified random sample: –A: General Population (30%) –B: Members over age 65 (70%) ► Population is a subset of a larger study on clinical and economic effects of cost-sharing

Questionnaire Measures - Adherence ► “Because of the amount you had to pay, have you”: –“taken less than the prescribed amount to make it last longer” –“not filled a prescription for a new medication” –“stopped refilling a prescription”

Questionnaire Measures - Burden ► “Because of the amount you had to pay, have you”: –“switched to a cheaper medication (e.g. generic)” –“gotten free medication samples from a doctor” –“gone to a non-Kaiser pharmacy instead” –“gotten help paying for medications through an [assistance] program” –“borrowed $ to pay for medications” –“gone without some necessity such as food, rent, heat, or other basics” –“bought a prescription medication in another country” –“bought a medication from an internet pharmacy”

Methods – Analysis ► Models: Multivariate logistic regression ► Predictor Measure: –Perceived/Actual Drug cost-sharing: Generic Copayment ($), Brand-Generic Copayment ($), Any Benefit Cap ► Outcome Measures –Decreased Adherence –Financial Burden ► Covariates –Socio-demographic: age, gender, race/ethnicity, marital status, household income, educational level –Clinical: self-reported health status, self-reported number of prescription drugs in previous 12 months, comorbidity (DxCG)

Figure 1. Study Design: Interview Participation n=932 (72%) *Ineligible = deceased, incapable of phone interview (e.g. hearing difficulties, dementia), non-English speaker, unable to be contacted KPNC Adult Population: Commercial and Medicare Population Interviewed n=254 (70%) Interviewed n=678 (73%) Refused n=251 (27%) Ineligible* n=261 Age 65+ (70%) n=1190 Overall Population (30%) n=510 Members Randomly Selected and Contacted for Interview n=1700 [2 Strata] Refused n=109 (30%) Ineligible* n=147

Table 1. Participant Characteristics CharacteristicTotal (n=932) % Sample A: Overall Pop. (n=254) % Sample B: Age 65+ (n=678) % Age Female Gender Non-white Race Education: less than College Graduate Married Household Income: < $35, Self Reported Health: Excellent or Very Good Persons with Any Prescription Meds w/in 12 mos Persons with Any ED Visits within 12 mos

Table 2. Knowledge of Drug Cost-Sharing Cost Sharing Type Any Cost-Sharing Amount of Cost Sharing Self- Report KP Actual Correctly Reported Under- estimate Exactly Correct Over- estimate %% % % Generic Copay Brand Name Tiered Copay Benefit Cap

Figure 2. Self-Reported Behavioral Response to Cost-sharing: Decreased Adherence

Figure 3. Self-Reported Behavioral Responses to Cost-sharing: Increased Burden

Table 3. Behavioral Response to Cost-sharing: Decreased Adherence Multivariate Logistic Regression Models Adjusted for Comorbidity *p=<0.10, †p=<0.05, ‡p=<0.01, CI= Confidence Interval CharacteristicSelf-Reported Cost-Sharing Actual Cost- Sharing OR95% CIOR95%CI Drug Cost-Sharing: Generic Copay ($) , , 1.14 Brand – Generic Copay ($) 1.01 † 1.00, , 1.11 Any Benefit Cap 2.37 ‡ 1.26, , 4.19 Age , † 0.16, 0.92 Female Gender , , 2.83 Non-White Race , , 2.49 Education: less than College Graduate 0.54*0.28, ‡ 0.24, 0.81 Married , , 2.61 Household Income < $35, ‡ 1.50, ‡ 1.54, 5.98 Health Excellent or Very Good , , 1.65 Number of RX’s used in 12 mos.: 0,1,2-4, † 1.04, ‡ 1.20, 3.18

Table 4. Behavioral Response to Cost-sharing: Increased Burden Multivariate Logistic Regression CharacteristicSelf-Reported Cost-Sharing Actual Cost- Sharing OR95% CIOR95% CI Drug Cost-Sharing: Generic Copay ($) 1.04*0.99, , 1.14 Brand – Generic Copay ($) 1.01 † 1.00, , 1.11 Any Benefit Cap 1.94 † 1.16, , 4.19 Age † 0.20, † 0.16, 0.92 Female Gender 1.96 † 1.15, , 2.83 Non-White Race , , 2.49 Education: less than College Graduate , ‡ 0.24, 0.81 Married 1.59*0.93, , 2.61 Household Income < $35, ‡ 1.73, ‡ 1.54, 5.98 Health Excellent or Very Good , , 1.65 Number of RX’s used in 12 mos.: 0,1,2-4, *0.97, ‡ 1.20, 3.18 Models Adjusted for Comorbidity *p=<0.10, †p=<0.05, ‡p=<0.01, CI= Confidence Interval

Limitations ► Single IDS with a range of delivery options ► English-speakers only ► Modest levels of cost-sharing ► Self-reports of behavioral responses ► No measure of clinical impact of behavioral responses

Conclusions ► Patients appeared to have general knowledge of their prescription drug cost-sharing, but limited knowledge about the amounts ► Nearly one in four patients changed their behavior in response to their perceived level of prescription drug cost- sharing –Over one in ten patients did not take their drugs as prescribed because of their perceived level of drug cost- sharing –Nearly one in five patients reported an increased burden in paying for their prescription medications

Implications ► The impact of drug cost-sharing on behavior may be attenuated due to limited knowledge of actual cost-sharing amounts ► Persons with more drug use or lower income may be more likely to change their behavior in response to drug cost- sharing ► Additional research is needed on the clinical and economic ramifications of prescription drug cost-sharing