Differences in cardiovascular disease risk when antihypertensive medication adherence is assessed by pharmacy fill versus self-report: the Cohort Study of Medication Adherence among Older Adults (CoSMO)

Medication adherence and persistence according to different antihypertensive drug classes: A retrospective cohort study of 255,500 patients

BACKGROUND

Suboptimal adherence to antihypertensives leads to adverse clinical outcomes. This study aims to determine and compare medication adherence and persistence to different first-line antihypertensive drug classes in a large cohort.

METHODS

A cohort study was performed using claims data for prescriptions in the German statutory health insurance scheme that insures approximately 90% of the population. A total of 255,500 patients with a first prescription of an antihypertensive were included and followed for 24months. Persistence was determined based on gaps in continuous dispensation. Adherence was analyzed by calculating the medication possession ratio (MPR).

RESULTS

Within a 2-year period, 79.3% of all incident users of antihypertensive monotherapy met the classification of non-persistence (gap >0.5 times the number of days supplied with medication) and 56.3% of non-adherence (MPR<0.8). Beta-blockers (42.5%) and angiotensin-converting enzyme inhibitors (31.9%) were the most widely prescribed drug classes. Non-persistence and non-adherence were highest for diuretics (85.4%, n=6149 and 66.3%, n=4774) and lowest for beta-blockers (77.6%, n=76,729 and 55.2%, n=54,559). The first gap of antihypertensive medication occurred in median 160-250days after initiation, and the average medication possession ratio for all drug classes was less than 0.8. Fixed combinations with diuretics showed a 19.8% lower chance for non-adherence (OR=0.802, 99.9% CI=[0.715-0.900], p<0.001) and an 8.4% lower hazard for non-persistence (HR 0.916, 99.9% CI=[0.863-0.973], p<0.001) compared with monotherapies.

CONCLUSIONS

This large cohort study reveals important differences in 2-year adherence and persistence between antihypertensives that were lowest for diuretics. Fixed-dose combinations with diuretics may facilitate adherence compared to single substance products. However, effective strategies to improve adherence to antihypertensives are needed regardless of drug class.

Medication Adherence and Incident Preventable Hospitalizations for Hypertension

INTRODUCTION

Potentially preventable hospitalizations (PPHs) for hypertension (HTN) is one indicator of possible failed ambulatory care. Rates of PPHs for HTN have remained fairly level since the late 1980s, which may reflect a lack of understanding of the drivers of these hospitalizations. Anti-HTN medication non-adherence has been studied as a potential risk factor for other cardiovascular disease outcomes but not for PPHs for HTN.

METHODS

A cohort analysis was conducted during 2005-2012 of people with HTN enrolled in commercial and employee health plans with claims in the MarketScan database. PPH for HTN was defined according to specifications published by the Agency for Healthcare Research and Quality. The proportion of days covered (PDC) algorithm was used to assess adherence to antihypertensives. Crude- and multivariate-adjusted incident PPHs for HTN rates were calculated, as well as third-party payments for selected PPH for HTN-related expenses.

RESULTS

During 9,344,528 person-years of follow-up (mean=3 years), 6,008 incident PPHs for HTN were identified among 3,099,291 people. The crude rate for good adherence (PDC ≥80%) was 23.2 per 100,000 person-years compared with 102.6 per 100,000 person-years for poor adherence (PDC <40%). Over the 8-year study, PPH for HTN-associated payments equaled $41 million. Payments for those with poor adherence were four times higher than for those with good adherence.

CONCLUSIONS

Poor anti-HTN medication adherence is strongly associated with PPHs for HTN. Improving the percentage of people who achieve good medication adherence is one possible approach to reducing the burden of PPHs for HTN in the U.S.

Effects of medication adherence on hospitalizations and healthcare costs in patients with schizophrenia in Thailand

Background:

This study was conducted to determine the impacts of medication adherence on hospitalization and direct healthcare cost in patients with schizophrenia in Thailand.

Methods:

A retrospective study was undertaken. Patients with schizophrenia aged 18–65 years who visited a University hospital and received antipsychotics from April 2011 to October 2011 were included. Propensity score–adjusted logistic regression was used to determine the impacts of medication adherence on schizophrenia-related and all-cause hospitalizations.

Results:

A total of 582 patients were included. Three out of 224 patients (1.3%) were hospitalized with schizophrenia in optimal adherence group, while 10 of 140 (7.1%) were hospitalized in under-adherence group, and 7 of 218 (3.2%) were hospitalized in over-adherence group. Based on propensity score–adjusted multivariate logistic regression, the adjusted odds ratio was 5.86 (95% confidence interval = 1.53–22.50) for schizophrenia-related hospitalization and 8.04 (95% confidence interval = 2.20–29.40) for all-cause hospitalization. The average annual direct healthcare costs in patients with optimal adherence, under-adherence, and over-adherence were US$371 ± US$836, US$386 ± US$734, and US$508 ± US$2168, respectively.

Conclusion:

An initiation of interventions to maintain optimal adherence in patients with schizophrenia would significantly impact the healthcare system.

Agreement between Medicare pharmacy claims, self-report, and medication inventory for assessing lipid-lowering medication use

BACKGROUND

Medicare claims have been used to study lipid-lowering medication (LLM) use among US adults.

METHODS

We analyzed the agreement between Medicare claims for LLM and LLM use indicated by self-report during a telephone interview and, separately, by a medication inventory performed during an in-home study visit upon enrollment into the REasons for Geographic And Racial Differences in Stroke (REGARDS) study. We included REGARDS participants ≥65 years enrolled in 2006-2007 with Medicare pharmacy benefits (Part D) from 120 days before their telephone interview through their medication inventory (n = 899).

RESULTS

Overall, 39.2% and 39.5% of participants had a Medicare claim for an LLM within 120 days prior to their interview and medication inventory, respectively. Also, 42.7% of participants self-reported using LLMs, and 41.8% had an LLM in their medication inventory. The Kappa statistic (95% confidence interval [CI]) for agreement of Medicare claims with self-report and medication inventory was 0.68 (0.63-0.73) and 0.72 (0.68-0.77), respectively. No Medicare claims for LLMs were present for 22.1% (95%CI: 18.1-26.6%) of participants who self-reported taking LLMs and 18.9% (15.1-23.3%) with LLMs in their medication inventory. Agreement between Medicare claims and self-report was lower among Black male individuals (Kappa = 0.34 [95%CI: 0.14-0.54]) compared with Black female individuals (0.70 [0.61-0.79]), White male individuals (0.65 [0.56-0.75]), and White female individuals (0.79 [0.72-0.86]). Agreement between Medicare claims and the medication inventory was also low among Black male individuals (Kappa = 0.48 [95%CI: 0.29-0.66]).

CONCLUSIONS

Although substantial agreement exists, many Medicare beneficiaries who self-report LLM use or have LLMs in a medication inventory have no claims for these medications. Copyright © 2016 John Wiley & Sons, Ltd.

The agreement of patient-reported versus observed medication adherence in type 2 diabetes mellitus (T2DM)

OBJECTIVE

Medication adherence in type 2 diabetes mellitus (T2DM) improves glycemic control and is associated with reduced adverse clinical events, and accurately assessing adherence assessment is important. We aimed to determine agreement between two commonly used adherence measures-the self-reported Morisky Medication Adherence Scale (MMAS) and direct observation of medication use by nurse practitioners (NPs) during home visits-and determine the relationship between each measure and glycated hemoglobin (HbA1c).

RESEARCH DESIGN AND METHODS

We evaluated agreement between adherence measures in the Southeastern Diabetes Initiative (SEDI) prospective clinical intervention home visit cohort, which included high-risk patients (n=430) in 4 SEDI-participating counties. The mean age was 58.7 (SD 11.6) years. The majority were white (n=210, 48.8%), female (n=236, 54.9%), living with a partner (n=316, 74.5%), and insured by Medicare/Medicaid (n=361, 84.0%). Medication adherence was dichotomized to 'adherent' or 'not adherent' using established cut-points. Inter-rater agreement was evaluated using Cohen's κ coefficient. Relationships among adherence measures and HbA1c were evaluated using the Wilcoxon rank-sum test and c-statistics.

RESULTS

Fewer patients (n=261, 61%) were considered adherent by self-reported MMAS score versus the NP-observed score (n=338; 79%). Inter-rater agreement between the two adherence measures was fair (κ=0.24; 95% CI 0.15 to 0.33; p<0.0001). Higher adherence was significantly associated with lower HbA1c levels for both measures, yet discrimination was weak (c-statistic=0.6).

CONCLUSIONS

Agreement between self-reported versus directly observed medication adherence was lower than expected. Though scores for both adherence measures were significantly associated with HbA1c, neither discriminated well for discrete levels of HbA1c.

Associations between adherence and outcomes among older, type 2 diabetes patients: evidence from a Medicare Supplemental database

OBJECTIVE

To examine the association between adherence to glucose-lowering agents and patient outcomes, including costs, acute-care resource utilization, and complications, in an older, type 2 diabetic population.

DATA AND METHODS

The study used Truven's Medicare Supplemental database from July 1, 2009 to June 30, 2014. Patients aged 65 years or older were included if they had at least two type 2 diabetes diagnoses and received a glucose-lowering agent from July 1, 2010 through June 30, 2011. Multivariable analyses examined the relationships among 3-year patient outcomes and levels of adherence, proxied by the proportion of days covered. Outcomes included all-cause medical costs, diabetes-related medical costs, acute-care resource utilization, and acute complications.

RESULTS

In this study (N=123,235), higher adherence was linked to reduced costs and improved health outcomes. For example, comparing an individual with adherence of proportion of days covered <20% to one with proportion of days covered ≥80% illustrates an average saving of $28,824 in total 3-year costs. Furthermore, a 1% increase in adherence among 1,000 patients was associated with all-cause savings of $65,464 over 3 years. The probability of a hospitalization, an emergency room (ER) visit, or an acute complication decreased monotonically as adherence levels got higher, as did the number of hospitalizations, ER visits, and days hospitalized (P<0.005).

CONCLUSION

Higher adherence was associated with substantially less need for acute care, as indicated by a lowered probability of hospitalization or ER use, a reduced risk of an acute complication, and a decreased number of hospitalizations, ER visits, and days hospitalized. Higher adherence was also generally associated with lower all-cause and diabetes-related total costs, despite higher drug costs. These lower total costs were driven by the diminished acute care and outpatient costs. Results suggest that higher glucose-lowering agent adherence is associated with significant benefits for payers and older patients with type 2 diabetes.

Medication Adherence Measures: An Overview

WHO reported that adherence among patients with chronic diseases averages only 50% in developed countries. This is recognized as a significant public health issue, since medication nonadherence leads to poor health outcomes and increased healthcare costs. Improving medication adherence is, therefore, crucial and revealed on many studies, suggesting interventions can improve medication adherence. One significant aspect of the strategies to improve medication adherence is to understand its magnitude. However, there is a lack of general guidance for researchers and healthcare professionals to choose the appropriate tools that can explore the extent of medication adherence and the reasons behind this problem in order to orchestrate subsequent interventions. This paper reviews both subjective and objective medication adherence measures, including direct measures, those involving secondary database analysis, electronic medication packaging (EMP) devices, pill count, and clinician assessments and self-report. Subjective measures generally provide explanations for patient's nonadherence whereas objective measures contribute to a more precise record of patient's medication-taking behavior. While choosing a suitable approach, researchers and healthcare professionals should balance the reliability and practicality, especially cost effectiveness, for their purpose. Meanwhile, because a perfect measure does not exist, a multimeasure approach seems to be the best solution currently.

Medication-taking behavior in hypertensive patients with a single-tablet, fixed-dose combination in Japan

Non-persistence rate (defined as not remaining on treatment) in patients taking a renin angiotensin system inhibitor plus calcium channel blocker was studied in three integrated 12-weeks surveys by matching separate drug combination therapy (CT) and fixed-dose combination (FDC). We also investigated medication adherence measured by proportion of days covered by using a claims database. The non-persistence rate was significantly lower in FDC than CT (p = 0.0074). In the database study, the medication adherence was higher in FDC than CT for 3, 6, and 12 months (all p < 0.001). In conclusion, use of single-tablet FDC antihypertensive therapy was associated with better medication-taking behavior.

Prevalence and Incidence of Hypertension in the General Adult Population: Results of the CARLA-Cohort Study

Hypertension is a leading cause of cardiovascular disease. There are very few studies dealing with the incidence of hypertension and changes in blood pressure (BP) over time. We aimed to evaluate the prevalence and incidence of hypertension within an adult population-based cohort.The sample included 967 men and 812 women aged 45 to 83 years at baseline, 1436 subjects completed follow-up1 after 4 years and 1079 completed follow-up2 after 9 years. BP was measured according to a standardized protocol with oscillometric devices and hypertension was defined as mean systolic BP (SBP) ≥140  mmHg and/or diastolic BP (DBP) ≥90  mmHg and/or use of antihypertensive medication if hypertension was known. We examined prevalence and incidence of hypertension, by age and sex.The age-standardized prevalence of hypertension at baseline was 74.3% for men and 70.2% for women. The age-standardized annual incidence rate of hypertension for men was 8.6 (95% confidence interval [95% CI] 4.3-12.9) for follow-up period1 and 5.4 (95% CI 2.8-10.6) for follow-up period2 and for women 8.2 (95% CI 3.6-12.8) for follow-up1 and 5.6 (95%CI 2.7-11.4) for follow-up2. A clear decrease in SBP and DBP between baseline and follow-up1 and follow-up2 was seen, accompanied by an increase in anti-hypertensive medication consumption and a higher awareness of the condition.Hypertension prevalence and incidence in the CARLA Study appear to be elevated compared with other studies. The decrease of BP over time seems to be caused by improved hypertension control due to interventional effects of our observational study and improved health care.