Antihypertensive Medication Adherence among Newly Treated Patients: Opportunities for Disparities Reduction?

Alyce S. Adams, PhD Connie Uratsu, RN Wendy Dyer, MSDavid Magid, MD, MPH Patrick O’Connor, MD, MA, MPH Arne Beck, PhD Melissa Butler, PhD P. Michael Ho, MD, PhD Julie A. Schmittdiel, PhD

18th Annual HMO Research NetworkConferenceApril 29-May 2, 2012Seattle, WA

AcknowledgementsINSTITUTIONSKaiser Permanente Division of Research, Oakland, CA; Institute for Research, Kaiser Permanente, Denver, CO; Kaiser Permanente Center for Health Research Southeast, Atlanta, GA; HealthPartners Research Foundation, Minneapolis, MN; Denver VA Medical Center, Denver, CO

FUNDERSNational Heart, Lung, and Blood Institute and the National Institute for Mental Health as a supplement to the HMO Research Network Cardiovascular Disease Network [3U19HL091179-04S1]. National Institute for Diabetes, Digestive and Kidney Diseases Health Delivery Systems Center for Diabetes Translational Research [P30DK092924] (Adams, Schmittdiel, O’Connor)

OTHERDr. Alan Go (critical edits), Ms. Karen R. Hansen (manuscript preparation)

Background

Conceptual Framework

Predisposing Factors•Beliefs about risks andbenefits of medicines•Medication Coverage

•Patient-Provider Relationship•Perceived affordability

Enabling Factors•Health Literacy/Education

•Patient self-care skills•Medication Affordability •Medication Tolerability

Race/EthnicityWhites•Blacks

•Hispanics•Asians

MediatorsHealth Status

IncomeEducationGeography

Rural/UrbanicitySocial Support

CulturePreferences

RacismStress

Perceived Barriers•Affordability/Ease of Access

•Competing Demands •Cognitive Issues/Complexity

Primary Non-Adherence

EarlyNon-Persistence

Non-Adherence

Research Questions

1. Are racial and ethnic differences in antihypertensive medication taking behavior consistent over time?

2. What factors contribute to differences in mediation takingBehavior at different stage of adherence by race andEthnicity?

Methods

Setting: Kaiser Permanente Northern California

Patients: Adults (≥18 years) with hypertension who were new users of antihypertensive therapy in 2008

Outcome Measures Primary non-adherence: failing to fill a prescribed antihypertensive agent within 60 days after it was ordered by physicianEarly non-persistence: failing to refill within 90 days of running out of the first prescription Non-adherence: not having medication available for 20% or more of days during the 12 months following initiation of therapy

Modeling: Multivariate logistic regression analysis, with sensitivity analyses using proc genmod and multiple imputation

Baseline Characteristics ALL White (non-

Hisp)Black (non-

Hisp)Asian (non-

Hisp)Hispanic

Race(msg/unk=37.2%)

44,167 16,343 (37.0%)

3,036 (6.9%)

3,893 (8.8%)

4,479 (10.1%)

Age: <50 18,122 (41.0%)

5,205 (31.9%)

1,650 (54.4%)

1,681 (43.2%)

2,330 (52.0%)

Female 21,796 (49.4%)

8,473 (51.8%)

1,789 (58.9%)

2,303 (59.2%)

2,445 (54.6%)

Smoking Status: Yes

4,653 (10.5%)

2,014 (12.3%)

473 (15.6%)

275 (7.1%)

409 (9.1%)

BMI (kg/m2) ≥30 14,668 (46.3%)

5,922 (45.6%)

1,436 (61.8%)

679 (22.9%)

2,151 (59.5%)

HH income < $40K 8304 (18.9%)

2553 (15.7%)

1158 (38.4%)

441 (11.4%)

1089 (24.5%)

Mean SBP (sd) † 144.3 (17.1) 144.0 (17.0) 145.1 (16.3) 142.9 (17.2) 143.5 (16.4)

Stages of Non-Adherence by Race/Ethnicity

05

1015202530354045

White (non-Hisp)

Black (non-Hisp)

Asian Hispanic

Primary Non-Adherent Early Non-PersistentNon-Adherent

Logistic Regression Model Estimating EarlyNon-Persistence with Antihypertensive Agents Black (non-

Hispanic)Asian (non-Hispanic)

Hispanic

Model 1: Age, Gender 1.59 (1.46-1.73) 1.36 (1.26-1.47) 1.48 (1.37-1.59)

+ smoking status, BMI, SBP 1.62 (1.49-1.77) 1.36 (1.26-1.47) 1.50 (1.40-1.62)

+ household income, medication copay

1.58 (1.45-1.73) 1.37 (1.26-1.48) 1.48 (1.38-1.60)

+physical comorbidity 1.58 (1.45-1.72) 1.36 (1.26-1.47) 1.48 (1.37-1.59)

+mental health comorbidity 1.59 (1.46-1.73) 1.37 (1.27-1.49) 1.48 (1.37-1.59)

+ physician visits 1.58 (1.45-1.73) 1.38 (1.27-1.49) 1.48 (1.37-1.59)

Logistic Regression Model Estimating Non-Adherence with Antihypertensive Agents

Black (non-Hispanic)

Asian (non-Hispanic)

Hispanic

Model 1: Age, Gender 1.73 (1.53-1.96) 1.20 (1.07-1.35) 1.68 (1.51-1.87)

+ smoking status, BMI, SBP 1.71 (1.51-1.94) 1.22 (1.08-1.37) 1.67 (1.51-1.86)

+ household income 1.67 (1.47-1.89) 1.22 (1.09-1.38) 1.65 (1.48-1.83)

+physical comorbidity 1.67 (1.47-1.90) 1.23 (1.09-1.38) 1.65 (1.48-1.84)

+mental health comorbidity 1.67 (1.47-1.90) 1.23 (1.09-1.39) 1.65 (1.48-1.84)

+ physician visits 1.68 (1.48-1.90) 1.23 (1.09-1.39) 1.65 (1.48-1.84)

+medication copay & mail order pharmacy use

1.54 (1.35-1.75) 1.13 (1.00-1.28) 1.48 (1.33-1.65)

Key Findings

• In this setting where patients have more or less equal access to care, non-white race was associated with both early non-persistence & non-adherence

• These relationships were robust to the inclusion of sociodemographic and clinical factors.

• However, the relationship between race/ethnicity and non-adherence was appreciably attenuated by the inclusion of medication copay and mail order pharmacy use.

Limitations

• Unmeasured confounders• beliefs and preferences unlikely to change over time• limits our understanding of differences and why they

occur• Logistic regression

• OR may overestimate effects, additional sensitivity analyses planned

• Missing Data• Results robust to multiple imputation

• Racial/Ethnic misclassification• may bias results if the misclassification is correlated

with both race/ethnicity and adherence

Conclusions

• Racial and ethnic differences in medication taking behavior occur early in the course of treatment.

• System level changes that ease access to medications may have the potential to attenuate persistent gaps in the use of these and other clinically effective therapies.

Thank you!

Contact: Alyce.S.Adams@kp.org