Chronic Illness and Multimorbidity

1. DRUG CHARACTERISTICS ASSOCIATED
WITH MEDICATION ADHERENCE
ACROSS EIGHT DISEASE STATES
Pamala A. Pawloski, PharmD1,2; Richard J Bruzek, PharmD2; Brita Hedblom1;
Steve Asche, MA1; Dana Meier, PharmD3; Cheri Rolnick, PhD, MPH1
1
HealthPartners Research Foundation, 2HealthPartners Pharmacy Services, 3Novartis Pharmaceutical
Corporation
HMORN Annual Meeting Wednesday, May 2, 2012, Seattle, WA

2. Background
 Medication non-adherence shown to be universally suboptimal
and believed to be a key factor in achieving therapeutic goals
 Non-adherence represents a multifaceted challenge among
patients and providers: leading to poor outcomes,
compromised health and serious economic consequences
 Determinants of non-adherence previously described as health
system, social/economic, therapy-related, condition-related,
and patient-related
 To date, the impact of drug characteristics on medication
adherence has not been studied across multiple disease states

3. Study Objective
 To describe medication adherence by drug
characteristics across 8 different disease states:
 drug class,
 generic utilization,
 average out-of-pocket cost/prescription
 To identify potential drug-specific factors by
disease that may serve as targets for future
intervention

4. Methods
 Retrospective analysis of patients with a single
diagnosis and oral medication for the following
conditions:
•Asthma/COPD
•Cancer
•Depression
•Diabetes
•Hypercholesterolemia
•Hypertension
•Multiple sclerosis (MS)
•Osteoporosis

5. Methods
 This study was conducted by HealthPartners
Research Foundation
 Integrated health system including 3 owned hospitals
and 27 owned clinics
 15 in-clinic pharmacies and a mail order pharmacy
 Serve >750,000 members
 Included all patients > 18 years with 1 of 8 medical
conditions described above

6. Methods
 Patient records were identified by ICD-9 DM for
diagnosis and GPI code for 128 medications of
interest through claims occurring between January
1, 2007 and March 31, 2009
• Diagnosis of interest must have occurred within 24
months of the most recent prescription fill
• A minimum of 2 prescription medication fills for at
least a 28-day supply

7. Methods
 Adherence was calculated by the Medication
Possession Ratio (MPR) for each patient based on
prescription fills within a 12-month window during
the study period
 Binary adherence (MPR >80%) by drug
characteristics within condition were tested with
contingency tables and chi-square tests

8. Methods
 Analysis was adjusted for sex, race, age,
proportion of adults with high school education,
and median income
 Logistic regression analysis was conducted to
examine predictors of adherence

9. Patient characteristics for patients with one
condition and one medication (n=14,875)
Total
%
N=14,875
Female 60.9
Race/ethnicity
White 82.8
African Am. 5.6
Asian 2.8
Hispanic 1.6
Am. Indian 0.5
Other 0.7
No answer 6.0
Age
18-49 30.4
50-59 26.2
60-69 20.7
70+ 22.7
Proportion of adults in living area
with a high school education
<88% 25.6
88-<93% 27.1
93-<96% 21.9
96%+ 25.5
Median=92.7%
Median income of families in
living area $64,500

10. Drug characteristics within condition
Asth/
Total Hyperten Depress Hyperlipid Diabetes Osteo Cancer MS
COPD
N=14,875 N=5,440 N=4,349 N=2,731 N=590 N=521 N=156 N=81
N=1,006
On
formulary 98.3 98.9 98.2 98.6 97.7 99.3 91.8 96.8 96.3
drug (%)
On
generic 75.7 91.6 74.6 66.7 22.8 85.6 78.9 41.7 0
drug (%)
Mean member amount paid per 30 days
0-$5 32.8 49.0 22.8 33.9 12.7 17.3 8.5 7.1 8.6
>$5-$12 39.1 38.2 46.4 38.0 16.2 52.4 31.5 27.6 8.6
>$12-$22 15.2 7.9 19.1 13.8 24.4 23.2 38.2 27.6 8.6
>$22-$50 11.2 4.5 10.6 12.6 39.6 6.1 18.8 31.4 45.7
>$50 1.6 0.4 1.2 1.5 7.2 1.0 3.1 6.4 28.4

11. Binary drug adherence (MPR >80%) by drug
characteristics, within condition
Asth/
Total Hyperten Depress Hyperlipid Diabetes Osteo Cancer MS
COPD
adherent adherent adherent adherent adherent adherent adherent adherent
adherent
N=14,875 N=5,440 N=4,349 N=2,731 N=590 N=521 N=156 N=81
N=1,007
Overall (%) 69.7 77.6 62.4 78.3 32.6 59.7 76.6 90.4 84.0
Generic vs.
brand (%)
Generic 70.9*** 77.3 60.6*** 78.8 18.8*** 59.0 79.6** 87.7 -
Brand 65.9 81.1 67.6 77.3 36.6 63.5 64.5 92.3 84.0
Mean member amount paid per 30 days
0-$5 72.3*** 78.3*** 55.4*** 82.0*** 30.5 51.0*** 52.3*** - -
>$5-$12 72.7 78.5 66.0 78.1 35.0 68.3 88.4 92.6 -
>$12-$22 64.1 70.7 60.0 77.5 36.7 51.8 77.4 90.7 81.0
>$22-$50 61.5 77.3 66.4 71.3 30.7 42.9 67.5 88.1 85.0
>$50 50.0 50.0 56.9 66.7 26.4 - - - -
* p<.05 **p<.01 ***p<.001 Pearson chi-square. N=20/row min for reporting.

12. Logistic regression: predicting adherence
within condition
Hyperten Depress Hyperlipid Asth/COPD Diabetes Osteo
% adherent % adherent % adherent % adherent % adherent % adherent
N=5,078 N=4,025 N=2,521 N=916 N=521 N=482
Brand vs. 2.82*** 1.61*** 1.56** 3.79*** 3.13** 0.67
generic (1.86-4.27) (1.34-1.94) (1.14-2.13) (2.47-5.81) (1.48-6.66) (0.37-1.21)
Mean member amount paid per 30 days
0-$5 Ref Ref Ref Ref Ref Ref
>$5-$12 0.92*** 1.45*** 0.61*** 1.52*** 2.01*** 5.75***
(0.79-1.06) (1.23-1.71) (0.58-0.78) 0.86-2.68 (1.19-3.41) (2.20-15.02)
>$12-$22 0.53 1.04 0.46 1.02 0.95 2.10
(0.40-0.69) (0.85-1.27) (0.31-0.67) 0.61-1.7 (0.53-1.70) (0.88-5.02)
>$22-$50 0.38 1.14 0.32 0.65 0.22 1.24
(0.23-0.62) (0.86-1.51) (0.21-0.49) 0.40-1.08 (0.08-0.64) (0.49-3.08)
>$50 0.16 0.59 0.22 0.38
(0.06-0.42) (0.32-1.09) (0.10-0.47) 0.18-0.80
C statistic 0.65 0.61 0.69 0.67 0.70 0.74
Odds ratio and 95%CI for odds ratio reported in table
Adjusted for sex, race (white/non-white), age, proportion of adults in living area with high school education, median income of families in the living area.
* p<.05 **p<.01 ***p<.001 - p values are associated with entire contrast rather than individual contrasts

13. Binary drug adherence (MPR >=80%) by drug
class, within condition
# adherent patients /
Condition, Drug class # patients taking the Unadjusted %
medication
Hypertension***
Calcium channel antagonists 391/477 82.0
Angiotensin II receptor antagonists 196/242 81.0
β-blockers, α/β-blockers 1315/1659 79.3
Angiotensin converting enzyme inhibitors 777/992 78.3
Antihypertensive combinations (non-diuretic) 574/734 78.2
Antihypertensive combinations (non-diuretic) 334/444 75.2
Diuretics 574/806 71.2
Peripherally acting anti-adrenergic agents 60/86 69.8
Depression**
SNRI1 359/506 71.0
Tricyclic antidepressants 118/172 68.6
SSRI2 1725-2775 62.2
Miscellaneous antidepressants 323/524 61.6
Miscellaneous antianxiety agents 33/63 52.4
Modified cyclic antidepressants 155/309 50.2

14. Binary drug adherence (MPR >=80%) by drug
class, within condition
# adherent patients/
Unadjusted
Condition, Drug class (cont) # patients taking the
%
medication
Hyperlipidemia***
HMG-CoA reductase inhibitors 1841/2311 79.7
Combination antihyperlipidemics 106/142 74.7
Intestinal cholesterol absorption inhibitors 67/90 74.4
Fibric acid derivatives 112/165 67.9
Nicotinic acid derivatives 12/23 52.2
Asthma/COPD***
Leukotriene modulators 93/140 66.4
Bronchodilators 34/52 65.4
Steroids 14/37 37.8
Adrenergics / combinations 139/431 32.3
Steroid inhalants 23/124 18.6
Nasally administered agents 25/223 11.2

15. Binary drug adherence (MPR >=80%) by drug
class, within condition
# adherent patients/
Unadjusted
Condition, Drug class (cont) # patients taking the
%
medication
Diabetes
Thiazolidinediones 41/56 73.2
Sulfonylureas 107/180 59.4
Biguanides 188/319 58.9
Antidiabetic combinations 8/15 53.3
GLP-1 receptor antagonists 8/20 40.0
Osteoporosis**
Bone density regulators 373/478 78.0
Hormone receptor modulators 15/20 75.0
Calcium 11/23 47.8
Cancer*
Antineoplastic hormonal agents/hormone 117/126 92.9
receptor modulators
Antineoplastic agents 24/30 80.0

16. Limitations
 Limited population to one diagnosis/medication to
identify to evaluate least-confounded population
 Small sample size occurred in some cells (across
member costs and some disease states)
 Generalizability may be limited due to the study
population occurring within an integrated health
system

17. Conclusions
 Variation in adherence rates by drug class
underscores the need to study adherence and
outcomes by both disease state and drug class
 Future steps include a continuous analysis of
adherence to determine changes across the
adherence spectrum by disease and drug class
 Correlating adherence to clinical outcomes is needed to
fully understand the meaning of adherence measures

18. Questions?

19. Study Population

20. MPR
Patient MPR = [(Σ Days Supplied – Days Supply of
Last Fill) / (LAST Fill Date – FIRST Fill Date)] * 100
 Mean MPR = (Σ Patients’ MPR / Number of patients
in the analysis) * 100