Association of Refill Adherence and Health Care Use Among Adults with Hypertension in an Urban Health Care System

The Effect of Telehealth on Patterns of Health Care Utilization and Medication Prescription in Patients with Diabetes or Hypertension During COVID-19: A Nationwide Study

Background: In response to the coronavirus disease-19 pandemic, audio-based telehealth services for consultation and medication prescription were temporarily introduced in Korea. This study investigated the impact of telehealth services on patterns of health care utilization and medication prescription in patients with hypertension or diabetes. Methods: The 2019 to 2021 Health Insurance Review and Assessment Service claims data were used. The difference-in-difference approach was used to investigate the effect of telehealth services between the case and control group before and after the intervention period. The pre-intervention period was from February 24, 2019, to February 23, 2020, and the post-intervention period from February 24, 2020, to February 23, 2021. The control group included individuals who used in-person outpatient services and the case group those who utilized both telehealth and in-person services. Results: A total of 250,640 patients with hypertension and 154,212 patients with diabetes were included. The use of telehealth services was associated with an increase in outpatient visits in those with hypertension (0.07, p = 0.0027) and diabetes (0.32, p < 0.0001). A decrease in hospitalizations (-0.2%, p = 0.0007) and emergency department visits (-0.11%, p = 0.0016) was found in individuals with hypertension. Policy implementation also resulted in an increase in medication possession ratio (MPR) and the proportion of appropriate prescription in patients with hypertension (MPR: 3.0%, p < 0.0001, prescription: 3.1%, p < 0.0001) and diabetes (MPR: 3.4%, p < 0.0001, prescription: 1.7%, p < 0.0001). Conclusions: The findings confirm a relationship between implementing telehealth services and improved patterns of health care utilization and medication prescription, suggesting the potential benefit of telehealth in managing chronic diseases.

[Effect of a Family Pharmacist System on Medication Adherence of Patients with Dyslipidemia during a COVID-19 Epidemic]

The pharmacy pharmacist's function as a family pharmacist is expected to improve adherence to medication in patients suffering from chronic diseases, including dyslipidemia. This is true even in infectious disease epidemics. In this study, using anonymously processed receipt data from 700 insurance pharmacies in our group, we evaluated medication adherence in patients taking statin drugs before, during the first and second years of coronavirus disease 2019 (COVID-19) epidemic in terms of medication persistence and medication possession, and compared the results between the family pharmacist group (FP group) and non-family pharmacist group (NoFP group). The odds ratios of good medication adherence (medication persistence and medication possession) rates for the FP group relative to the NoFP group were 1.446 [95% confidence interval (CI): 1.210-1.727] in the pre-epidemic period, 1.428 (1.192-1.710) in the first year of the epidemic, and 1.270 (1.113-1.450) in the second year of the epidemic. The FP group was significantly higher in all time periods. Therefore, it is suggested that the family pharmacist function improves adherence to statins not only before but also during the COVID-19 epidemic.

Delta T, a Useful Indicator for Pharmacy Dispensing Data to Monitor Medication Adherence

INTRODUCTION

Calculating patients' medication availability from dispensing or refill data is a common method to estimate adherence. The most often used measures, such as the medication possession ratio (MPR), average medication supplies over an arbitrary period. Averaging masks the variability of refill behavior over time.

GOAL

To derive a new absolute adherence estimate from dispensing data.

METHOD

Dispensing histories of patients with 19 refills of direct oral anticoagulants (DOAC) between 1 January 2008 and 31 December 2017 were extracted from 39 community pharmacies in Switzerland. The difference between the calculated and effective refill day (ΔT) was determined for each refill event. We graphed ΔT and its dichotomized version (dΔT) against the MPR, calculated mean ΔT and mean dΔT per refill, and applied cluster analysis.

RESULTS

We characterized 2204 refill events from 116 DOAC patients. MPR was high (0.975 ± 0.129) and showed a positive correlation with mean ΔT. Refills occurred on average 17.8 ± 27.9 days "too early", with a mean of 75.8 ± 20.2 refills being "on time". Four refill behavior patterns were identified including constant gaps within or at the end of the observation period, which were critical.

CONCLUSION

We introduce a new absolute adherence estimate ΔT that characterizes every refill event and shows that the refill behavior of DOAC patients is dynamic.

Patient Possession of Excess Medication Supply in the VA: A Retrospective Database Study

BACKGROUND

Medication overlap leading to medication excess is a form of therapeutic duplication, itself a type of potentially inappropriate prescribing.

OBJECTIVE

To determine the prevalence of potential medication excess in the Veterans Health Administration (VHA) and identify associated medication-level, patient-level, and system-level factors.

RESEARCH DESIGN

A retrospective database study.

SUBJECTS

All veterans who received ≥1 prescription dispensed by a VHA pharmacy in fiscal year 2014.

MEASURES

The primary outcome of "medication excess" was defined for each patient as the number of excess days' worth of medications for all overlap episodes (concurrently dispensed medications with the same name for >10 d). Predictors included medication-level, patient-level, and system-level factors. Multivariable negative binomial regression analyses estimated the rate ratio of each predictor with medication excess.

RESULTS

Among 4,687,453 veterans, 64% had ≥1 medication overlap episodes. Patients were prescribed a median of 7 [interquartile range (IQR), 3-12] unique medications, had a median of 2 (IQR, 0-5) overlap episodes, and a median of 27 (IQR, 0-96) days of medication excess. In adjusted regression models, factors associated with greater risk of medication excess included having more comorbidities, multiple prescribers, a combination of filling locations (consolidated mail-order pharmacy vs. local pharmacy), and multiple prescription durations (≥90 d vs. less).

CONCLUSIONS

Medication excess was high among VHA users, with nearly two-thirds of patients experiencing at least 1 duplicative medication. As systems such as mail-order pharmacies and 90-day supply are increasingly implemented to reduce costs and improve medication adherence, it is important to recognize the potential for systems-level inefficiencies and potentially inappropriate prescribing.

Effect of Dual Use of Veterans Affairs and Medicare Part D Drug Benefits on Antihypertensive Medication Supply in a National Cohort of Veterans with Dementia

OBJECTIVE

To evaluate the effect of dual use of VA/Medicare Part D drug benefits on antihypertensive medication supply in older Veterans with dementia.

DATA SOURCES/STUDY SETTING

National, linked 2007-2010 Veterans Affairs (VA) and Medicare utilization and prescription records for 50,763 dementia patients with hypertension.

STUDY DESIGN

We used inverse probability of treatment (IPT)-weighted multinomial logistic regression to examine the association of dual prescription use with undersupply and oversupply of antihypertensives.

DATA COLLECTION/EXTRACTION METHODS

Veterans Affairs and Part D prescription records were used to classify patients as VA-only, Part D-only, or dual VA/Part D users of antihypertensives and summarize their antihypertensive medication supply in 2010: (1) appropriate supply of all prescribed antihypertensive classes, (2) undersupply of ≥1 class with no oversupply of another class, (3) oversupply of ≥1 class with no undersupply, or (4) both undersupply and oversupply.

PRINCIPAL FINDINGS

Dual prescription users were more likely than VA-only users to have undersupply only (aOR = 1.28; 95 percent CI = 1.18-1.39), oversupply only (aOR = 2.38; 95 percent CI = 2.15-2.64), and concurrent under- and oversupply (aOR = 2.89; 95 percent CI = 2.53-3.29), versus appropriate supply of all classes.

CONCLUSIONS

Obtaining antihypertensives through both VA and Part D was associated with increased antihypertensive under- and oversupply. Efforts to understand how best to coordinate dual-system prescription use are critically needed.

Adherence trajectories of buprenorphine therapy among pregnant women in a large state Medicaid program in the United States

PURPOSE

Little is known about the longitudinal patterns of buprenorphine adherence among pregnant women with opioid use disorder, especially when late initiation, nonadherence, or early discontinuation of buprenorphine during pregnancy may increase the risk of adverse outcomes. We aimed to identify distinct trajectories of buprenorphine use during pregnancy, and factors associated with these trajectories in Medicaid-enrolled pregnant women.

METHODS

A retrospective cohort study included 2361 Pennsylvania Medicaid enrollees aged 15 to 46 having buprenorphine therapy during pregnancy and a live birth between 2008 and 2015. We used group-based trajectory models to identify buprenorphine use patterns in the 40 weeks prior to delivery and 12 weeks postdelivery. Multivariable multinomial logistic regression models were used to identify factors associated with specific trajectories.

RESULTS

Six distinct trajectories were identified. Four groups initiated buprenorphine during the first trimester of the pregnancy (early initiators): 31.6% with persistently high adherence, 15.1% with moderate-to-high adherence, 10.5% with declining adherence, and 16.7% with early discontinuation. Two groups did not initiate buprenorphine until midsecond or third trimester (late initiators): 13.5% had moderate-to-high adherence and 12.6% had low-to-moderate adherence. Factors significantly associated with late initiation and discontinuation were younger age, non-white race, residents of rural counties, fewer outpatient visits, more frequent emergency department visits and hospitalizations, and lower buprenorphine daily dose.

CONCLUSIONS

Six buprenorphine treatment trajectories during pregnancy were identified in this population-based Medicaid cohort, with 25% of women initiating buprenorphine late during pregnancy. Understanding trajectories of buprenorphine use and factors associated with discontinuation/nonadherence may guide integration of behavioral treatment with obstetrical/gynecological care to improve buprenorphine treatment during pregnancy.

Eye Drop Dispenser Type and Medication Possession Ratio in Patients With Glaucoma: Single-Use Containers Versus Multiple-Use Bottles

PURPOSE

To determine whether the consumption of topical glaucoma medication is influenced by the type of eye drop dispenser.

DESIGN

Retrospective cohort study.

METHODS

We examined 366 patients with open-angle glaucoma or ocular hypertension who were bilaterally treated with 0.0015% tafluprost or 2% dorzolamide/0.5% timolol fixed combination (DTFC). The patients were grouped by the type of dispenser and content of eye drops used: (1) tafluprost in bottles (T-Bottle group); (2) tafluprost in unit-dose pipettes (T-Unit group); (3) DTFC in bottles (C-Bottle group); and (4) DTFC in unit-dose pipettes (C-Unit group). We evaluated the medication possession ratio (MPR) among groups, and factors associated with over-consumption (MPR > 1.2) or under-consumption (MPR < 0.8) in multinomial logistic regression.

RESULTS

The mean MPR was 1.49 (range, 0.69-2.91) in the T-Bottle group, 0.91 (range, 0.32-1.27) in the T-Unit group, 1.25 (range, 0.51-2.60) in the C-Bottle group, and 0.96 (range, 0.36-1.60) in the C-Unit group. The Bottle groups demonstrated higher mean values and wider ranges of MPR compared to the Unit groups. The MPR interval at which the largest number of patients were found was 1.0-1.4 in the Bottle groups and 0.8-1.2 in the Unit groups. Bottle-type dispenser (odds ratio [OR] 64.02), tafluprost medication (OR 2.84), and older age (OR 1.03) were associated with over-consumption, whereas no factor was correlated with under-consumption.

CONCLUSIONS

The type of eye drop dispenser affects the consumption of glaucoma medication. Physicians should consider the type of eye drop dispenser when assessing glaucoma medication adherence.

Economic impact of medication non-adherence by disease groups: a systematic review

OBJECTIVE

To determine the economic impact of medication non-adherence across multiple disease groups.

DESIGN

Systematic review.

EVIDENCE REVIEW

A comprehensive literature search was conducted in PubMed and Scopus in September 2017. Studies quantifying the cost of medication non-adherence in relation to economic impact were included. Relevant information was extracted and quality assessed using the Drummond checklist.

RESULTS

Seventy-nine individual studies assessing the cost of medication non-adherence across 14 disease groups were included. Wide-scoping cost variations were reported, with lower levels of adherence generally associated with higher total costs. The annual adjusted disease-specific economic cost of non-adherence per person ranged from $949 to $44 190 (in 2015 US$). Costs attributed to 'all causes' non-adherence ranged from $5271 to $52 341. Medication possession ratio was the metric most used to calculate patient adherence, with varying cut-off points defining non-adherence. The main indicators used to measure the cost of non-adherence were total cost or total healthcare cost (83% of studies), pharmacy costs (70%), inpatient costs (46%), outpatient costs (50%), emergency department visit costs (27%), medical costs (29%) and hospitalisation costs (18%). Drummond quality assessment yielded 10 studies of high quality with all studies performing partial economic evaluations to varying extents.

CONCLUSION

Medication non-adherence places a significant cost burden on healthcare systems. Current research assessing the economic impact of medication non-adherence is limited and of varying quality, failing to provide adaptable data to influence health policy. The correlation between increased non-adherence and higher disease prevalence should be used to inform policymakers to help circumvent avoidable costs to the healthcare system. Differences in methods make the comparison among studies challenging and an accurate estimation of true magnitude of the cost impossible. Standardisation of the metric measures used to estimate medication non-adherence and development of a streamlined approach to quantify costs is required.

PROSPERO REGISTRATION NUMBER

CRD42015027338.

Evaluation of the chronic disease management program for appropriateness of medication adherence and persistence in hypertension and type-2 diabetes patients in Korea

The chronic disease management program (CDMP), a multilevel intervention including copayment reduction and physician incentives, was introduced in 2012 in Korea to improve blood pressure and glycemic control by strengthening the function of clinic as primary care institutions in managing hypertension and diabetes. This study, therefore, aimed to evaluate the effect of CDMP on the appropriateness of medication adherence and persistence in hypertension or type-2 diabetes patients.A pre-post retrospective study was conducted using claims cohort data from 2010 to 2013. Hypertension or type-2 diabetes patients were selected as the CDMP group, while dyslipidemia patients were the control group. Study groups were further categorized as clinic shifters or non-shifters on the basis of whether hospital use changed to clinic use during the study period. Pre-post changes in adherence and persistence were assessed. Adherence was measured by medication possession ratio (MPR) and categorized as under (<0.8), appropriate (0.8-1.1), and over-adherence (>1.1). Persistence was measured by 12-month cumulative persistence rate.The pre-post change was significantly improved for appropriate-adherence (hypertension, +6.0%p; diabetes, +6.1%p), 12-month cumulative persistence (hypertension, +6.5%p; diabetes, +10.8%p), and over-adherence (hypertension, -5.3%p; diabetes, -2.8%p) only among the shifters in the CDMP group. Among these, patients visiting the same, single clinic showed a significant increase in appropriate-adherence, whereas those who changed their clinics showed a nonsignificant increase. No significant improvement was verified among the non-shifters in the CDMP group.CDMP improved medication adherence and persistence by significantly increasing appropriate-adherence and 12-month cumulative persistence rate in hypertension and type-2 diabetes patients. Particularly, CDMP significantly improved over-adherence, which was associated with increasing healthcare costs and hospitalization risk.

Trajectories of Diabetes Medication Adherence and Hospitalization Risk: A Retrospective Cohort Study in a Large State Medicaid Program

BACKGROUND

Numerous interventions are available to boost medication adherence, but the targeting of these interventions often relies on crude measures of poor adherence. Group-based trajectory models identify individuals with similar longitudinal prescription filling patterns. Identifying distinct adherence trajectories may be more useful for targeting interventions, although the association between adherence trajectories and clinical outcomes is unknown.

OBJECTIVE

To examine the association between adherence trajectories for oral hypoglycemics and subsequent hospitalizations among diabetes patients.

DESIGN

Retrospective cohort study.

PATIENTS

A total of 16,256 Pennsylvania Medicaid enrollees, non-dually eligible for Medicare, initiating oral hypoglycemics between 2007 and 2009.

MAIN MEASURES

We used group-based trajectory models to identify trajectories of oral hypoglycemics in the 12 months post-treatment initiation, using monthly proportion of days covered (PDC) as the adherence measure. Multivariable Cox proportional hazard models were used to examine the association between trajectories and time to first diabetes-related hospitalization/emergency department (ED) visits in the following year. We used the C-index to compare prediction performance between adherence trajectories and dichotomous cutpoints (annual PDC <80 vs. ≥80 %).

RESULTS

The mean annual PDC was 0.58 (SD 0.32). Seven trajectories were identified: perfect adherers (9 % of the cohort), nearly perfect adherers (31.4 %), moderate adherers (21.0 %), low adherers (11.0 %), late discontinuers (6.8 %), early discontinuers (9.7 %), and non-adherers with only one fill (11.1 %). Compared to perfect adherers, trajectories of moderate adherers (HR = 1.48, 95 % CI 1.25, 1.75), low adherers (HR = 1.51, 95 % CI 1.25, 1.83), and non-adherers with only one fill (HR = 1.35, 95 % CI 1.09, 1.67) had greater risk of diabetes-related hospitalizations/ED visits. Predictive accuracy was improved using trajectories compared to dichotomized cutpoints (C-index = 0.714 vs. 0.652).

CONCLUSIONS

Oral hypoglycemic treatment trajectories were highly variable in this large Medicaid cohort. Low and moderate adherers and those filling only one prescription had a modestly higher risk of hospitalizations/ED visits compared to perfect adherers. Trajectory models may be valuable in identifying specific non-adherence patterns for targeting interventions.

Association between trajectories of buprenorphine treatment and emergency department and in-patient utilization

BACKGROUND AND AIMS

Uncertainty about optimal treatment duration for buprenorphine opioid agonist therapy may lead to substantial variation in provider and payer decision-making regarding treatment course. We aimed to identify distinct trajectories of buprenorphine use and examine outcomes associated with these trajectories to guide health system interventions regarding treatment length.

DESIGN

Retrospective cohort study.

SETTING

US Pennsylvania Medicaid.

PATIENTS

A total of 10 945 enrollees aged 18-64 years initiating buprenorphine treatment between 2007 and 2012.

MEASUREMENTS

Group-based trajectory models were used to identify trajectories based on monthly proportion of days covered with buprenorphine in the 12 months post-treatment initiation. We used separate multivariable Cox proportional hazard models to examine associations between trajectories and time to first all-cause hospitalization and emergency department (ED) visit within 12 months after the first-year treatment.

FINDINGS

Six trajectories [Bayesian information criterion (BIC) = -86 246.70] were identified: 24.9% discontinued buprenorphine < 3 months, 18.7% discontinued between 3 and 5 months, 12.4% discontinued between 5 and 8 months, 13.3% discontinued > 8 months, 9.5% refilled intermittently and 21.2% refilled persistently for 12 months. Persistent refill trajectories were associated with an 18% lower risk of all-cause hospitalizations [hazard ratio (HR) = 0.82, 95% confidence interval (CI) = 0.70-0.95] and 14% lower risk of ED visits (HR = 0.86, 95% CI = 0.78-0.95) in the subsequent year, compared with those discontinuing between 3 and 5 months.

CONCLUSIONS

Six distinct buprenorphine treatment trajectories were identified in this population-based low-income Medicaid cohort in Pennsylvania, USA. There appears to be an association between persistent use of buprenorphine for 12 months and lower risk of all-cause hospitalizations/emergency department visits.

Medication oversupply in patients with diabetes

BACKGROUND

Studies in integrated health systems suggest that patients often accumulate oversupplies of prescribed medications, which is associated with higher costs and hospitalization risk. However, predictors of oversupply are poorly understood, with no studies in Medicare Part D.

OBJECTIVE

The aim of this study was to describe prevalence and predictors of oversupply of antidiabetic, antihypertensive, and antihyperlipidemic medications in adults with diabetes managed by a large, multidisciplinary, academic physician group and enrolled in Medicare Part D or a local private health plan.

METHODS

This was a retrospective cohort study. Electronic health record data were linked to medical and pharmacy claims and enrollment data from Medicare and a local private payer for 2006-2008 to construct a patient-quarter dataset for patients managed by the physician group. Patients' quarterly refill adherence was calculated using ReComp, a continuous, multiple-interval measure of medication acquisition (CMA), and categorized as <0.80 = Undersupply, 0.80-1.20 = Appropriate Supply, >1.20 = Oversupply. We examined associations of baseline and time-varying predisposing, enabling, and medical need factors to quarterly supply using multinomial logistic regression.

RESULTS

The sample included 2519 adults with diabetes. Relative to patients with private insurance, higher odds of oversupply were observed in patients aged <65 in Medicare (OR = 3.36, 95% CI = 1.61-6.99), patients 65+ in Medicare (OR = 2.51, 95% CI = 1.37-4.60), patients <65 in Medicare/Medicaid (OR = 4.55, 95% CI = 2.33-8.92), and patients 65+ in Medicare/Medicaid (OR = 5.73, 95% CI = 2.89-11.33). Other factors associated with higher odds of oversupply included any 90-day refills during the quarter, psychotic disorder diagnosis, and moderate versus tight glycemic control.

CONCLUSIONS

Oversupply was less prevalent than in previous studies of integrated systems, but Medicare Part D enrollees had greater odds of oversupply than privately insured individuals. Future research should examine utilization management practices of Part D versus private health plans that may affect oversupply.

Understanding medication oversupply and its predictors in the outpatient departments in Thailand

BACKGROUND

Medication oversupply is an important problem in the healthcare systems. It causes unnecessary avoidable healthcare costs. Although some studies have determined the magnitude and financial loss due to medication oversupply in western countries, they may not be applicable to Asia-pacific countries. This study aims to determine the prevalence, financial loss, and patterns of medication oversupply and the factors associated with such oversupply in Thailand.

METHODS

A retrospective database analysis was used from 3 public hospitals. Patients visiting the outpatient department of the hospitals in 2010 and receiving at least 2 prescriptions within 6 months were included. The modified medication possession ratio (MPRm) was used to determine the medication supply. Patients having MPRm > 1.20 were defined as receiving a medication oversupply. The measures were prevalence of medication oversupply, the number of oversupplied medications, and financial loss (2012 dollars) due to medication oversupply. Hierarchical logistic regression was used to determine the factors associated with the prevalence of medication oversupply.

RESULTS

A total of 99,743 patients were included. Patients were on average 49.7 ± 21.2 years of age, and 42.8% were male. Most of them were adult (53.7%). Among those patients, 60.2% of the patients were under universal coverage schemes. Around 13.4% of all the patients received a medication oversupply, and the patients in regional hospitals had a higher prevalence of medication oversupply than patients in district hospitals (13.8% VS 8.2%). The patients under civil servant medical benefit schemes (CSMBS) (13.6%) had the most prevalence of medication oversupply. The total financial loss was $189,024 per year. The average financial loss was $1.9 ± 19.0 per patient/year. Patients under CSMBS experienced the highest average financial loss (2.6 ± 23.2 $/patient/year). Age, gender, health insurance schemes, and the number of medications that the patients received were the factors associated with medication oversupply.

CONCLUSIONS

Medication oversupply is an important problem for the health system. Patients receiving care from regional hospitals had a higher likelihood of medication oversupply. Policymakers may consider developing policies for preventing medication oversupply. The policy should be implemented in regional hospitals and especially in children or patients with poly-pharmacy.

Medication supply, healthcare outcomes and healthcare expenses: longitudinal analyses of patients with type 2 diabetes and hypertension

INTRODUCTION

Patients with chronic conditions largely depend on proper medications to maintain health. This study aims to examine, for patients with diabetes and hypertension, whether the appropriateness of the quantity of drug obtained is associated with favorable healthcare outcomes and lower expenses.

METHODS

This study utilized a longitudinal design with a seven-year follow-up period from 2002 to 2009 under a universal health insurance program in Taiwan. The patients under study were those aged 18 years or older and newly diagnosed with type 2 diabetes or hypertension in 2002. Generalized estimating equations were performed to examine the relationship between medication supply and health outcomes as well as expenses.

RESULTS

The results indicate that while compared with patients with an appropriate medication supply, patients with either an undersupply or an oversupply of medications tended to have poorer healthcare outcomes. The study also found that an excess supply of medications for patients with diabetes or hypertension resulted in higher total healthcare expenses.

CONCLUSION

Either an undersupply or an oversupply of medication was associated with unfavorable healthcare outcomes, and that medication oversupply was associated with the increased consumption of health resources. Our findings suggest that improving appropriate medication supply is beneficial for the healthcare system.

Refill adherence and self-reported adverse drug reactions and sub-therapeutic effects: a population-based study

PURPOSE

To assess refill adherence to dispensed oral long-term medications among the adult population and to investigate whether the percentages of self-reported adverse drug reactions (ADRs) and sub-therapeutic effects (STEs) differed for medications with adequate refill adherence, oversupply, and undersupply.

METHOD

Survey responses on self-reported ADRs and STEs were linked to the Swedish Prescribed Drug Register in a cross-sectional population-based study. Refill adherence to antihypertensive, lipid-lowering, and oral anti-diabetic medications was measured using the continuous measure of medication acquisition (CMA). The percentages of self-reported ADRs and STEs were compared between medications with adequate refill adherence (CMA 0.8-1.2), oversupply (CMA > 1.2), and undersupply (CMA < 0.8).

RESULTS

The study included 1827 persons, and the refill adherence was measured for 3014 antihypertensive, 839 lipid lowering, and 253 oral anti-diabetic medications. Overall, 65.7% of the medications had adequate refill adherence, 21.9% oversupply, and 12.4% undersupply. The percentages of self-reported ADRs and STEs were respectively 2.6%, 2.7%, and 2.1% (p > 0.5) for ADRs and 1.1%, 1.6%, and 1.5% (p > 0.5) for STEs.

CONCLUSIONS

Adequate refill adherence was found in two thirds of the medication therapies. ADRs and STEs were unexpectedly equally commonly reported for medications with adequate refill adherence, oversupply, and undersupply. These results suggest that a better understanding of patients' refill behaviors and their perceived medication adverse outcomes is needed and should be considered in improving medication management. The impact of individual and healthcare factors that may influence the association between refill adherence and reported medication adverse outcomes should be investigated in future studies.

Physician assessments of medication adherence and decisions to intensify medications for patients with uncontrolled blood pressure: still no better than a coin toss

Background

Many patients have uncontrolled blood pressure (BP) because they are not taking medications as prescribed. Providers may have difficulty accurately assessing adherence. Providers need to assess medication adherence to decide whether to address uncontrolled BP by improving adherence to the current prescribed regimen or by intensifying the BP treatment regimen by increasing doses or adding more medications.

Methods

We examined how provider assessments of adherence with antihypertensive medications compared with refill records, and how providers’ assessments were associated with decisions to intensify medications for uncontrolled BP. We studied a cross-sectional cohort of 1169 veterans with diabetes presenting with BP ≥140/90 to 92 primary care providers at 9 Veterans Affairs (VA) facilities from February 2005 to March 2006. Using VA pharmacy records, we utilized a continuous multiple-interval measure of medication gaps (CMG) to assess the proportion of time in prior year that patient did not possess the prescribed medications; CMG ≥20% is considered clinically significant non-adherence. Providers answered post-visit Likert-scale questions regarding their assessment of patient adherence to BP medications. The BP regimen was considered intensified if medication was added or increased without stopping or decreasing another medication.

Results

1064 patients were receiving antihypertensive medication regularly from the VA; the mean CMG was 11.3%. Adherence assessments by providers correlated poorly with refill history. 211 (20%) patients did not have BP medication available for ≥ 20% of days; providers characterized 79 (37%) of these 211 patients as having significant non-adherence, and intensified medications for 97 (46%). Providers intensified BP medications for 451 (42%) patients, similarly whether assessed by provider as having significant non-adherence (44%) or not (43%).

Conclusions

Providers recognized non-adherence for less than half of patients whose pharmacy records indicated significant refill gaps, and often intensified BP medications even when suspected serious non-adherence. Making an objective measure of adherence such as the CMG available during visits may help providers recognize non-adherence to inform prescribing decisions.

Prevalence and correlates of low medication adherence in apparent treatment-resistant hypertension

Low medication adherence may explain part of the high prevalence of apparent treatment-resistant hypertension (aTRH). The authors assessed medication adherence and aTRH among 4026 participants taking ≥ 3 classes of antihypertensive medication in the population-based Reasons for Geographic and Racial Differences in Stroke (REGARDS) trial using the 4-item Morisky Medication Adherence Scale (MMAS). Low adherence was defined as an MMAS score ≥ 2. Overall, 66% of participants taking ≥ 3 classes of antihypertensive medication had aTRH. Perfect adherence on the MMAS was reported by 67.8% and 70.9% of participants with and without aTRH, respectively. Low adherence was present among 8.1% of participants with aTRH and 5.0% of those without aTRH (P<.001). Among those with aTRH, female sex, residence outside the US stroke belt or stroke buckle, physical inactivity, elevated depressive symptoms, and a history of coronary heart disease were associated with low adherence. In the current study, a small percentage of participants with aTRH had low adherence.

Estimation of financial burden due to oversupply of medications for chronic diseases

Given the potential of financial burden due to oversupply of medications for chronic diseases, this study aims to determine the prevalence of oversupply and to estimate the magnitude of financial loss in Thailand. Electronic patient database in a university-affiliated hospital in Thailand was used. Based on the utilization of top 5 high drug expenditure in 2005, the prevalence and the financial loss of oversupply (medication possession ratio [MPR] >1.00) were estimated. In total, 1893 patients were included in this study. The average age was 65.2 years and the majority were female (56%). The prevalence of oversupply ranged from 23.2% to 62.8%, whereas the annual financial loss ranged from US $4108 to US $10 517. The total amount of loss was US $32 903 or 3.77% of total medication costs. In summary, because of the high prevalence and associated high financial loss, oversupply of medication is a significant financial burden on hospitals and society.

Antihypertensive medication adherence, ambulatory visits, and risk of stroke and death

BACKGROUND

This study seeks to determine whether antihypertensive medication refill adherence, ambulatory visits, and type of antihypertensive medication exposures are associated with decreased stroke and death for community-dwelling hypertensive patients.

METHODS

This retrospective cohort study included all chronic medication-treated hypertensives enrolled in Tennessee's Medicaid program (TennCare) for 3-7 years during the period 1994-2000 (n = 49,479). Health care utilization patterns were evaluated using administrative data linked to vital records during a 2-year run-in period and 1- to 5-year follow-up period. Antihypertensive medication refill adherence was calculated using pharmacy records.

RESULTS

Associations with stroke and death were assessed using Cox proportional hazards modeling. Stroke occurred in 619 patients (1.25%) and death in 2,051 (4.15%). Baseline antihypertensive medication refill adherence was associated with decreased multivariate hazards of stroke [hazard ratio (HR) 0.91; 95% confidence interval (CI), 0.86-0.97 for 15% increase in adherence]. Adherence in the follow-up period was associated with decreased hazards of stroke (HR 0.92; CI 0.87-0.96) and death (HR 0.93; CI 0.90-0.96). Baseline ambulatory visits were associated with decreased death (HR 0.99; CI 0.98-1.00). Four major classes of antihypertensive agents were associated with mortality reduction. Only thiazide-type diuretic use was associated with decreased stroke (HR 0.89; CI 0.85-0.93).

CONCLUSIONS

Ambulatory visits and antihypertensive medication exposures are associated with reduced mortality. Increasing adherence by one pill per week for a once-a-day regimen reduces the hazard of stroke by 8-9% and death by 7%.

Prospective validation of eight different adherence measures for use with administrative claims data among patients with schizophrenia

OBJECTIVE

The aim of this study was to compare the predictive validity of eight different adherence measures by studying the variability explained between each measure and hospitalization episodes among Medicaid-eligible persons diagnosed with schizophrenia on antipsychotic monotherapy.

METHODS

This study was a retrospective analysis of the Arkansas Medicaid administrative claims data. Continuously eligible adult schizophrenia (ICD-9-CM = 295.**) patients on antipsychotic monotherapy were identified in the recruitment period from July 2000 through April 2004. Adherence rates to antipsychotic therapy in year 1 were calculated using eight different measures identified from the literature. Univariate and multivariable logistic regression models were used to prospectively predict all-cause and mental health-related hospitalizations in the follow-up year.

RESULTS

Adherence rates were computed for 3395 schizophrenic patients with a mean age of 42.9 years, of which 52.5% (n = 1782) were females, and 52.8% (n = 1793) were white. The proportion of days covered (PDC) and continuous measure of medication gaps measures of adherence had equal C-statistics of 0.571 in predicting both all-cause and mental health-related hospitalizations. The medication possession ratio (MPR) continuous multiple interval measure of oversupply were the second best measures with equal C-statistics of 0.568 and 0.567 for any-cause and mental health-related hospitalizations. The multivariate adjusted models had higher C-statistics but provided the same rank order results.

CONCLUSIONS

MPR and PDC were among the best predictors of any-cause and mental health-related hospitalization, and are recommended as the preferred adherence measures when a single measure is sought for use with administrative claims data for patients not on polypharmacy.

Good and poor adherence: optimal cut-point for adherence measures using administrative claims data

OBJECTIVE

To identify the adherence value cut-off point that optimally stratifies good versus poor compliers using administratively derived adherence measures, the medication possession ratio (MPR) and the proportion of days covered (PDC) using hospitalization episode as the primary outcome among Medicaid eligible persons diagnosed with schizophrenia, diabetes, hypertension, congestive heart failure (CHF), or hyperlipidemia.

RESEARCH DESIGN AND METHODS

This was a retrospective analysis of Arkansas Medicaid administrative claims data. Patients > or =18 years old had to have at least one ICD-9-CM code for the study diseases during the recruitment period July 2000 through April 2004 and be continuously eligible for 6 months prior and 24 months after their first prescription for the target condition. Adherence rates to disease-specific drug therapy were assessed during 1 year using MPR and PDC. MAIN OUTCOME MEASURE AND ANALYSIS SCHEME: The primary outcome measure was any-cause and disease-related hospitalization. Univariate logistic regression models were used to predict hospitalizations. The optimum adherence value was based on the adherence value that corresponded to the upper most left point of the ROC curve corresponding to the maximum specificity and sensitivity.

RESULTS

The optimal cut-off adherence value for the MPR and PDC in predicting any-cause hospitalization varied between 0.63 and 0.89 across the five cohorts. In predicting disease-specific hospitalization across the five cohorts, the optimal cut-off adherence values ranged from 0.58 to 0.85.

CONCLUSIONS

This study provided an initial empirical basis for selecting 0.80 as a reasonable cut-off point that stratifies adherent and non-adherent patients based on predicting subsequent hospitalization across several highly prevalent chronic diseases. This cut-off point has been widely used in previous research and our findings suggest that it may be valid in these conditions; it is based on a single outcome measure, and additional research using these methods to identify adherence thresholds using other outcome metrics such as laboratory or physiologic measures, which may be more strongly related to adherence, is warranted.

Challenges for scaling up ART in a resource-limited setting: a retrospective study in Kibera, Kenya

OBJECTIVE

To determine levels of dropout and adherence in an antiretroviral treatment (ART) program in sub-Saharan Africa's largest urban informal settlement, Kibera, in Nairobi, Kenya.

METHOD

Retrospective cohort study.

RESULTS

: Of 830 patients that started ART between January 2005 and September 2007, 29% dropped out of the program for more than 90 days at least once after the last prescribed dose. The dropout rate was 23 per 100 person-years, and the probability of retention in the program at 6, 12, and 24 months was 0.83, 0.74, and 0.65, respectively. Twenty-seven percent of patients had an overall mean adherence below 95%. Being a resident of Kibera was significantly associated with 11 times higher risk of dropout.

CONCLUSION

Despite free drugs and low associated costs, dropout probabilities in this study are higher and adherence to ART is lower compared with other studies from sub-Saharan Africa. Our results illustrate that ART programs in resource-limited settings, such as Kibera, risk low adherence and retention rates when expanding services. Specific and intensified patient support is needed to minimize the risk of dropout and nonadherence causing future significant health threats not only to individuals but also to public health.

Contrasting measures of adherence with simple drug use, medication switching, and therapeutic duplication

BACKGROUND

Multiple measures of adherence have been reported in the research literature and it is difficult to determine which is best, as each is nuanced. Occurrences of medication switching and polypharmacy or therapeutic duplication can substantially complicate adherence calculations when adherence to a therapeutic class is sought.

OBJECTIVE

To contrast the Proportion of Days Covered (PDC) adherence metric with 2 variants of the Medication Possession Ratio (MPR, truncated MPR).

METHODS

This study was a retrospective analysis of the North Carolina Medicaid administrative claims data from July 1999 to June 2000. Data for patients with schizophrenia (ICD-9-CM code 295.xx) who were not part of a health maintenance organization, not hospitalized, and not pregnant, taking at least one antipsychotic, were aggregated for each person into person-quarters. The numerator for PDC was defined as the number of days one or more antipsychotics was available and the MPR numerator was defined as the total days' supply of antipsychotics; both were divided by the total days in each person-quarter. Adherence rates were estimated for subjects who used only one antipsychotic, switched medications, or had therapeutic duplication in the quarter.

RESULTS

The final sample consisted of 25,200 person-quarters from 7069 individuals. For person-quarters with single antipsychotic use, adherence to antipsychotics as a class was: PDC 0.607, truncated MPR 0.640, and MPR 0.695 (p < 0.001). For person-quarters with switching, the average MPR was 0.690, truncated MPR was 0.624, and PDC was 0.562 (p < 0.001). In the presence of therapeutic duplication, the PDC was 0.669, truncated MPR was 0.774, and MPR was 1.238 (p < 0.001).

CONCLUSIONS

The PDC provides a more conservative estimate of adherence than the MPR across all types of users; however, the differences between the 2 methods are more substantial for persons switching therapy and prescribed therapeutic duplication, where MPR may overstate true adherence. The PDC should be considered when a measure of adherence to a class of medications is sought, particularly in clinical situations in which multiple medications within a class are often used concurrently.

Importance of socioeconomic status as a predictor of cardiovascular outcome and costs of care in women with suspected myocardial ischemia. Results from the National Institutes of Health, National Heart, Lung and Blood Institute-sponsored Women's Ischemia Syndrome Evaluation (WISE)

BACKGROUND

For women, who are more likely to live in poverty, defining the clinical and economic impact of socioeconomic factors may aid in defining redistributive policies to improve healthcare quality.

METHODS

The NIH-NHLBI-sponsored Women's Ischemia Syndrome Evaluation (WISE) enrolled 819 women referred for clinically indicated coronary angiography. This study's primary end point was to evaluate the independent contribution of socioeconomic factors on the estimation of time to cardiovascular death or myocardial infarction (MI) (n = 79) using Cox proportional hazards models. Secondary aims included an examination of cardiovascular costs and quality of life within socioeconomic subsets of women.

RESULTS

In univariable models, socioeconomic factors associated with an elevated risk of cardiovascular death or MI included an annual household income <$20,000 (p = 0.0001), <9th grade education (p = 0.002), being African American, Hispanic, Asian, or American Indian (p = 0.016), on Medicaid, Medicare, or other public health insurance (p < 0.0001), unmarried (p = 0.001), unemployed or employed part-time (p < 0.0001), and working in a service job (p = 0.003). Of these socioeconomic factors, income (p = 0.006) remained a significant predictor of cardiovascular death or MI in risk-adjusted models that controlled for angiographic coronary disease, chest pain symptoms, and cardiac risk factors. Low-income women, with an annual household income <$20,000, were more often uninsured or on public insurance (p < 0.0001) yet had the highest 5-year hospitalization and drug treatment costs (p < 0.0001). Only 17% of low-income women had prescription drug coverage (vs. >or=50% of higher-income households, p < 0.0001), and 64% required >or=2 anti-ischemic medications during follow-up (compared with 45% of those earning >or=$50,000, p < 0.0001).

CONCLUSIONS

Economic disadvantage prominently affects cardiovascular disease outcomes for women with chest pain symptoms. These results further support a profound intertwining between poverty and poor health. Cardiovascular disease management strategies should focus on policies that track unmet healthcare needs and worsening clinical status for low-income women.

What factors contribute to the inadequate control of elevated blood pressure?

Inadequate control of blood pressure may be attributed to both provider-related and patient-related factors. Health care provider-related factors may include an excessive reliance on monotherapy and reluctance to increase drug doses or add additional antihypertensive agents to the treatment regimen. The primary patient-related factor is nonadherence with the prescribed antihypertensive medication. Although the high cost of therapy is sometimes a reason for poor adherence, drug side effects or dosing considerations may be more important factors. Better adherence with antihypertensive medication is associated with a significantly greater likelihood of achieving blood pressure control and, consequently, with lower costs and reduced utilization of health care resources. Therefore, strategies that improve long-term adherence should be adopted. Single-pill, or fixed-dose, combination therapy is one approach that improves adherence, while also providing the antihypertensive efficacy needed to help patients achieve their blood pressure goals.