Methods for evaluation of medication adherence and persistence using automated databases

Adherence to Antihypertensive Medications and Cardiovascular Morbidity Among Newly Diagnosed Hypertensive Patients

Background— Nonadherence to antihypertensive treatment is a common problem in cardiovascular prevention and may influence prognosis. We explored predictors of adherence to antihypertensive treatment and the association of adherence with acute cardiovascular events.

Methods and Results— Using data obtained from 400 Italian primary care physicians providing information to the Health Search/Thales Database, we selected 18 806 newly diagnosed hypertensive patients ≥35 years of age during the years 2000 to 2001. Subjects included were newly treated for hypertension and initially free of cardiovascular diseases. Patient adherence was subdivided a priori into 3 categories—high (proportion of days covered, ≥80%), intermediate (proportion of days covered, 40% to 79%), and low (proportion of days covered, ≤40%)—and compared with the long-term occurrence of acute cardiovascular events through the use of multivariable models adjusted for demographic factors, comorbidities, and concomitant drug use. At baseline (ie, 6 months after index diagnosis), 8.1%, 40.5%, and 51.4% of patients were classified as having high, intermediate, and low adherence levels, respectively. Multiple drug treatment (odds ratio, 1.62; 95% CI, 1.43 to 1.83), dyslipidemia (odds ratio, 1.52; 95% CI, 1.24 to 1.87), diabetes mellitus (odds ratio, 1.40; 95% CI, 1.15 to 1.71), obesity (odds ratio, 1.50; 95% CI, 1.26 to 1.78), and antihypertensive combination therapy (odds ratio, 1.29; 95% CI, 1.15 to 1.45) were significantly ( P <0.001) associated with high adherence to antihypertensive treatment. Compared with their low-adherence counterparts, only high adherers reported a significantly decreased risk of acute cardiovascular events (hazard ratio, 0.62; 95% CI, 0.40 to 0.96; P =0.032).

Conclusions— The long-term reduction of acute cardiovascular events associated with high adherence to antihypertensive treatment underscores its importance in assessments of the beneficial effects of evidence-based therapies in the population. An effort focused on early antihypertensive treatment initiation and adherence is likely to provide major benefits.

Duloxetine compliance and its association with healthcare costs among patients with diabetic peripheral neuropathic pain

OBJECTIVE

Duloxetine is approved to treat diabetic peripheral neuropathic pain (DPNP) in the US. The study objective was to examine the predictors of duloxetine compliance, and its association with healthcare costs among DPNP patients.

METHODS

The study used administrative claims databases to identify non-depressed DPNP patients with a duloxetine prescription dispensed between October 1, 2004 and December 31, 2006. Two cohorts of patients were constructed based on compliance to duloxetine therapy over 1-year follow-up with high compliance defined as a medication possession ratio (MPR) > or =0.80. All-cause, diabetes-, and DPNP-related healthcare costs during 1-year follow-up were estimated. Logistic regressions were performed to examine how average daily dose (ADD) of duloxetine and other factors may influence compliance. Multivariate regressions were estimated to examine the association between compliance and healthcare costs.

RESULTS

The study included 1,380 commercially insured (mean age 55 years) and 974 patients with employer-sponsored Medicare supplemental insurance (mean age 75 years). In both populations, patients with an ADD >30 mg were more likely to be compliant with the therapy compared with those with an ADD of < or =30 mg (odds ratio ranged 1.79-3.38, all p<0.05). Controlling for differences in demographics, clinical and economic characteristics, commercially insured low duloxetine compliance patients had greater all-cause ($5,334, p<0.05) and diabetes-related healthcare costs ($3,414, p<0.05) than high-compliance patients, with the biggest difference from inpatient costs (all-cause: $7,508; diabetes-related: $3,785, all p<0.05). Similar trends were found in the Medicare supplemental insured population; however, differences in all-cause healthcare costs were not significant.

CONCLUSIONS

DPNP patients with a higher ADD of duloxetine over a 1-year follow-up period were more compliant with the therapy. Duloxetine patients with high compliance were also associated with lower healthcare costs. Due to the use of a retrospective cohort design on administrative claims database, limitations of this analysis include a lack of formal diagnostic testing of patients, and inability to infer causality or measure factors such as DPNP severity that are not captured in such database.

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.

ChronoMedIt--a computational quality audit framework for better management of patients with chronic conditions

BACKGROUND

Quality audit and feedback to general practice is an important aspect of successful chronic disease management. However, due to the complex temporal relationships associated with the nature of chronic illness, formulating clinically relevant queries within the context of a specific evaluation period is difficult.

METHODS

We abstracted requirements from a set of previously developed criteria to develop a generic criteria model that can be used to formulate queries related to chronic condition management. We implemented and verified the framework, ChronoMedIt, to execute clinical queries within the scope of the criteria model.

RESULTS

Our criteria model consists of four broad classes of audit criteria - lapse in indicated therapy, no measurement recording, time to achieve target and measurement contraindicating therapy. Using these criteria classes as a guide, ChronoMedIt has been implemented as an extensible framework. ChronoMedIt can produce criteria reports and has an integrated prescription and measurement timeline visualisation tool. We illustrate the use of the framework by identifying patients on suboptimal therapy based on a range of pre-determined audit criteria using production electronic medical record data from two general medical practices for 607 and 679 patients with hypertension. As the most prominent result, we find that 59% (out of 607) and 34% (out of 679) of patients with hypertension had at least one episode of >30day lapse in their antihypertensive therapy over a 12-month evaluation period.

CONCLUSIONS

ChronoMedIt can reliably execute a wide range of clinically useful queries to identify patients whose chronic condition management can be improved.

Better adherence to antihypertensive agents and risk reduction of chronic heart failure

AIMS

Antihypertensive (AH) agents have been shown to reduce the risk of major cardiovascular events including chronic heart failure (CHF). However, the impact of changes in patterns of AH agents use on CHF is unknown. Our objective was to estimate to which different patterns of AH agent use is associated with the occurrence of CHF in a population-based study.

METHOD AND RESULTS

A cohort of 82 320 patients was reconstructed using the Régie de l'assurance maladie du Québec's databases. Patients were eligible if they were between 45 to 85 years of age, had no indication of cardiovascular disease and were newly treated with AH therapy between 1999 and 2004. A nested case-control design was used to study the occurrence of CHF. Every case of CHF was matched for age and duration of follow-up to a maximum of 15 randomly selected controls. Adherence level was reported as a medication possession ratio. Conditional logistic regression models were used to estimate the rate ratio (RR) of CHF adjusting for different covariables. The mean patient age was 65 years, 37% were male, 8% had diabetes, 19% had dyslipidaemia and mean time of follow-up at 2.7 years. High adherence level (95%) to AH therapy compared with lower adherence level (60%) was associated with an additional reduction of CHF events (RR: 0.89; 0.80-0.99). Risk factors for CHF were being on social assistance, diabetes, dyslipidaemia, higher chronic disease score and developing a cardiovascular condition during follow-up.

CONCLUSION

Our study suggests that a better adherence is associated with a significant risk reduction of CHF. Adherence to AH therapy needs to be improved to optimize benefits.

A computational framework to identify patients with poor adherence to blood pressure lowering medication

BACKGROUND

Blood pressure (BP) lowering medications have impressive efficacy in reducing cardiovascular and renal events; but low adherence threatens their effectiveness. Analysis of patterns in electronic prescribing from electronic medical records (EMRs) may have the potential to reveal cohorts of patients with significant adherence problems.

METHODS

We developed a computational framework to identify patient cohorts with poor adherence to long-term medication through analysis of electronic prescribing patterns. A range of quality reporting criteria can be specified (as an XML document). We illustrate the framework by application to the EMRs of a New Zealand general practice with a focus on adherence to angiotensin-converting enzyme inhibitors (ACE-inhibitors) and/or angiotensin II receptor blockers (ARBs) in patients classified with hypertension and diabetes. We analyse medication supply based on Medication Possession Ratio (MPR) and duration of lapse in ACE-inhibitors/ARBs over a 12-month evaluation period. We describe graphical tools to assist visualisation of prescribing patterns and relationship of the analysis outputs to controlled blood pressure.

RESULTS

Out of a cohort of 16,504 patient EMRs, 192 patients were found classified with both hypertension and diabetes and under active ACE-inhibitor and/or ARB management. Of these, 107 (56%) patients had an ACE-inhibitor/ARB MPR less than 80% together with a lapse in ACE-inhibitors/ARBs for greater than 30 days. We find non-adherent patients (i.e. MPR <80% or lapse >30 days) are three times more likely to have poor BP than adherent patients (odds ratio=3.055; p=0.012).

CONCLUSIONS

We have developed a generic computational framework that can be used to formulate and query criteria around issues of adherence to long-term medication based on practice EMRs. Within the context of the example we have used, the observed adherence levels indicate that a substantial proportion of patients classified with hypertension and diabetes have poor adherence, associated with poorer rates of blood pressure control, that can be detected through analysis of electronic prescribing. Further work is required to identify effective interventions using the reporting information to reduce non-adherence and improve patient outcomes.

Medication adherence: its importance in cardiovascular outcomes

Medication adherence usually refers to whether patients take their medications as prescribed (eg, twice daily), as well as whether they continue to take a prescribed medication. Medication nonadherence is a growing concern to clinicians, healthcare systems, and other stakeholders (eg, payers) because of mounting evidence that it is prevalent and associated with adverse outcomes and higher costs of care. To date, measurement of patient medication adherence and use of interventions to improve adherence are rare in routine clinical practice. The goals of the present report are to address (1) different methods of measuring adherence, (2) the prevalence of medication nonadherence, (3) the association between nonadherence and outcomes, (4) the reasons for nonadherence, and finally, (5) interventions to improve medication adherence.

Measuring Persistence to Oral Hypoglycemic Agents in Type 2 Diabetic Veterans

BACKGROUND: Medication adherence is essential for diabetes control but difficult to measure. Persistence, the continuous refill of medications, is one measurement that could be integrated into practice, but concordance among definitions of persistence is unclear. OBJECTIVE: To compare persistence patterns in the use of oral hypoglycemic agents by diabetic veterans in the first year of treatment, using 2 separate refill metrics. METHODS: Eligible veterans were 18 years or older and had filled at least one prescription for any nondiabetes drug during the 6 months preceding study entry. Study entry was the date that patients first filled a prescription for oral hypoglycemic agents between January 1,2000, and December 31, 2002. Persistence was defined as (1) total days (days' supply/study period) and (2) continuous fill (days' supply/refill interval). RESULTS: Inclusion criteria were met by 110,554 veterans. They had a median age of 63 years, 97% were male, and most had multiple comorbidities. Most patients received only one oral hypoglycemic agent. When total days was used, median persistence at 1 year was 83%, with 45% of subjects demonstrating poor persistence (<80%). When continuous fill was used, median persistence was 0.99, and 24% had poor persistence. Both metrics decreased over time. Continuous fill produced higher persistence estimates and a substantial proportion of overpersistence (>24% of patients). The 2 measures had a kappa agreement statistic of 0.56 (95% CI 0.55 to 0.57). CONCLUSIONS: Although both metrics showed similar trajectories over time, more conservative estimates, ease of calculation, and transparency favor total days over continuous fill. Continuous fill revealed substantial overpersistence, which should be considered separately from good persistence. Explicit definitions of persistence are necessary to enhance comparisons among refill studies and provide context for clinical applications.

Medication adherence and persistence in severe obstructive sleep apnea

STUDY OBJECTIVE

The aim of this study was to compare 2 groups of patients with severe obstructive sleep apnea (OSA) who were taking medication for cardiovascular disease: those who were compliant with nasal continuous positive airway pressure (CPAP) treatment and those who refused treatment or were noncompliant with CPAP treament.

METHODS

In a cohort of 2158 patients with severe OSA (apnea-hypopnea index >30) a 2-year prospective longitudinal assessment of adherence and persistence with 3 medication categories (antihypertensives, statins, and antiplatelets) was carried out using the administrative database of the National Health Service. Medication adherence was evaluated by calculating the medication possession ratio (%MPR = days supplylactual days to refill x 100) for each drug. Medication persistency was defined as the proportion of subjects having filled a prescription in the last 30 days of the 2-year period. CPAP use was assessed at every follow-up visit after the treatment was prescribed. Medication adherence was compared between patients who had adequate CPAP adherence (> 4 h/day) and those who declined CPAP therapy or had discontinued CPAP due to an average use of less than 4 hours per day.

RESULTS

The average 2-year MPR for antihypertensives, statins, and antiplatelets was not different among patients who used CPAP (88%, 81%, 95%) or did not use CPAP (86%, 77%, 93%). Female sex and increased number of comorbidities were predictors of good medication adherence (MPR > 80%). The rates of persistence for the 3 studied medications after the 2-year observation period were not different between the 2 groups (patients with or without CPAP).

CONCLUSIONS

Medication adherence and persistence during a 2-year period for 3 well-known protective cardiovascular medications were not different in patients with severe OSA, whether or not they were treated with CPAP.

Impact of better adherence to statin agents in the primary prevention of coronary artery disease

BACKGROUND

Statins reduce cardiovascular morbidity and mortality after continuous treatment. Studies have shown that less than 50% of patients take 80% or more of prescribed doses 1 year after starting therapy.

OBJECTIVE

To evaluate the impact of statin adherence on the incidence of coronary artery disease (CAD).

METHODS

A cohort of 115,290 patients was reconstructed using the Régie de l'assurance maladie du Québec databases. Patients aged 45 to 85 years, without indication of cardiovascular disease (CVD), and newly treated with statins between 1999 and 2004 were eligible. A nested case-control design was used to study CAD. Every case was matched for age and duration of follow-up with randomly selected controls. The adherence level was measured by calculating the medication possession ratio. Rate ratios (RR) of CAD were determined through conditional logistic regression adjusted for several covariates.

RESULTS

The mean patient age was 63 years, 54% had hypertension, 26% had diabetes, and 41% were males. The proportion of patients with high adherence level to statins (> or = 80%) was 74% during the first year and 53% after 1 year of follow-up. High adherence was associated with a risk reduction of 18% [RR: 0.82 (95% CI: 0.77-0.87)] compared to an adherence level of <20%. Developing a CVD during follow-up, being male, having been diagnosed with hypertension or diabetes, or having a high chronic disease score increased the risk of CAD.

CONCLUSION

Our study suggests that better adherence to statin agents is associated with a significant risk reduction of CAD. Adherence to statin agents needs to be improved so that patients can benefit from the full protective effects of statin therapies.

Drug-adherence questionnaires not valid for patients taking blood-pressure-lowering drugs in a primary health care setting

PURPOSE

To validate two established questionnaires [Morisky and Medication Adherence Report Scale (MARS-5)] for the measurement of medical adherence of patients treated with antihypertensive drugs in primary care in Germany.

SETTING

General practitioners (GPs) and their patients in North Rhine-Westphalia, Germany.

METHODS

GPs were asked to recruit 12 consecutive patients using blood-pressure-lowering medication for at least 12 months. Patients were asked to fill out both the Morisky and MARS-5 questionnaires. The medication possession ratio (MPR) was calculated as reference standard for patients' medication adherence by using GPs' electronic patient records. The results of the questionnaires were then compared with the reference standard.

RESULTS

A total of 14 GPs recruited 163 patients of which 128 were included in the analysis. Of the 128 patients, 52% were females; the age ranged from 44 to 96 years (mean 71). The overall adherence rate measured by the MPR was 62.1%. Compared to the reference standard, the Morisky Scale had a sensitivity of 31.9%, a specificity of 72.8% and a positive likelihood ratio (+LR) of 1.18. The MARS-5 had a sensitivity of 8.5%, a specificity of 97.4% and a +LR of 3.28.

CONCLUSION

The Morisky Scale and the MARS-5 cannot be recommended for measuring the adherence to antihypertensive drugs in a general practice setting in Germany at this point. These results emphasize the necessity to validate questionnaires in a specific setting before using them as instruments within a trial different from the original setting(s) of validation.

Trends in RA patients' adherence to subcutaneous anti-TNF therapies and costs

OBJECTIVE

To examine adherence to adalimumab (ADA) and etanercept (ETA) and health care costs in rheumatoid arthritis (RA) patients, and to explore the association between adherence, utilization and costs.

RESEARCH DESIGN AND METHODS

Using administrative claims data from a large managed health care plan, RA patients treated with etanercept or adalimumab during the period from 01/01/2005 through 12/31/2005 were identified. The first dispensing date was defined as the index date. Patient adherence and costs were assessed during the 1 year post-index period.

MAIN OUTCOME MEASURES

Nonadherence (medication possession ratio <80%) was modeled using logistic regression. Hazard ratios (HR) comparing time to discontinuation were estimated using Cox proportional hazard (PH) models. Propensity score matching with multivariate generalized linear modeling adjustment was done to assess cost difference between ADA and ETA.

RESULTS

Of 3829 eligible RA patients, 1292 (765 existing, 527 naïve) and 2537 (1834 existing, 703 naïve) patients used ADA and ETA, respectively. Compared with ADA users, ETA users had longer average treatment duration (316 vs. 291 days; p < 0.0001). Unadjusted adherence rates for naïve and existing users were 63% and 70% (ADA), and 65% and 73% (ETA). Logistic regression analysis indicated that compared with ETA users, ADA users were more likely to be nonadherent (OR, naïve 1.24; existing; 1.25). Cox PH models indicated that existing ADA users were more likely to discontinue (HR = 1.11; p = 0.06) their medication than existing ETA users. Compared with ADA users, ETA users had significantly lower RA-related pharmacy costs (naïve: $10,892 vs. $12,534, p < 0.01; existing: $12,192 vs. $13,752, p < 0.01) and RA-related total costs (naïve: $11,976.42 vs. $13,511.99, p < 0.05; existing: $14,031 vs. $15,454, p < 0.05).

CONCLUSIONS

ETA users had longer treatment duration, were more likely to adhere to their medication regimen and had lower RA-related pharmacy and RA-related total costs compared with ADA users. These findings must be considered within the limitations of this database analysis.

Best clinical and research practice in epilepsy of older people: Focus on antiepileptic drug adherence

Few studies have examined the issues that are specific to the older person with epilepsy, a population of increasing prominence in epilepsy management. Our understanding of the impact of epilepsy in the older person is based predominantly on what is inferred from studies of younger adults. Consequently, there is relatively little documented about the impact of epilepsy on the everyday lives of older people. In this article, we focus on adherence and its consequences for the physical, social, and psychological well-being of the older person. A number of strategies are proposed to improve adherence, including patient education through better communication between physician and patient; simplification of the medical regime; and use of extended-release formulations. This issue highlights that to ameliorate the impact of epilepsy for the older person with epilepsy, a greater understanding is required so that appropriate interventions can be tailored.

Adjuvant hormonal therapy use among insured, low-income women with breast cancer

PURPOSE Use of adjuvant hormonal therapy, which significantly decreases breast cancer mortality, has not been well described among poor women, who are at higher risk of cancer-related death. Here we explore use of adjuvant hormonal therapy in an insured, low-income population. METHODS A North Carolina Cancer Registry-Medicaid linked data set was used. Women with hormone receptor-positive or unknown, nonmetastatic breast cancer, diagnosed between 1998 and 2002, were included. Main outcomes were (1) prescription fill within 1 year of diagnosis, (2) adherence (medication possession ratio), and (3) persistence (absence of a 90-day gap in prescription fills over 12 months). Results The population consisted of 1,491 women (mean age, 67 years). Sixty-four percent filled prescriptions. Predictors of prescription fill included the following: older age (odds ratio [OR], 1.01; P = .017), greater number of prescription medications (OR, 1.06; P < .001), nonmarried status (OR, 1.82; P = .001), higher stage (OR, 1.83; P < .001), positive hormone receptor status (positive v unknown, OR, 1.98; P < .001), not receiving adjuvant chemotherapy (OR, 1.74; P = .001), receipt of adjuvant radiation (OR, 1.55; P = .004), and treatment in a small hospital (OR, 1.49; P = .024). Adherence and persistence rates were 60% and 80%, respectively. Nonmarried status predicted greater adherence (OR, 1.90; P = .006) and persistence (OR, 1.75; P = .031). CONCLUSION Prescription fill, adherence, and persistence to adjuvant hormonal therapy among socioeconomically disadvantaged women are low. Improving use of adjuvant hormonal therapy may lead to lower breast cancer-specific mortality in this population.

Clopidogrel Adherence following Percutaneous Coronary Intervention with a Drug-Eluting Stent in a VA Medical Center

Background:

Antiplatelet therapy with aspirin and a thienopyridine is the standard of care for prevention of thrombosis following coronary stent implantation. Recent evidence suggests a prolonged risk of stent thrombosis; therefore, clopidogrel therapy for at least 1 year is recommended following implantation of a drug-eluting stent. Premature discontinuation of clopidogrel is a well-recognized risk factor for stent thrombosis.

Objective:

To identify the rate of adherence to clopidogrel therapy among patients who have undergone percutaneous coronary intervention (PCI).

Methods:

We queried the central Veteran Affairs (VA) pharmacy database for each patient who underwent PCI with a drug-eluting stent between September 2004 and August 2005 at a single VA medical center. Based on pharmacy refill records, patients were considered adherent to clopidogrel if they filled more than 80% of the clopidogrel prescriptions.

Results:

We observed that 20.3% of patients were nonadherent to clopidogrel therapy for the course that they were assigned. Shorter duration of therapy was the only factor that predicted increased adherence. Race, polypharmacy, marital status, prior clopidogrel use, and age did not have a significant impact on adherence. Multivariable analysis did not demonstrate any other significant relationships.

Conclusions:

In this high-risk cohort of patients who have undergone PCI, we observed a 20% incidence of nonadherence to clopidogrel therapy. Shorter duration of therapy had a significant impact on improving rates of adherence in our analysis. This observation is of particular concern given the recent recommendations to prolong antiplatelet therapy to at least 1 year following PCI with a drug-eluting stent.

Adherence with urate-lowering therapies for the treatment of gout

Introduction

Adherence to urate-lowering drugs (ULDs) has not been well evaluated among those with gout. Our aim was to assess the level and determinants of non-adherence with ULDs prescribed for gout.

Methods

We identified persons using two integrated delivery systems aged 18 years or older with a diagnosis of gout who initiated use of allopurinol, probenecid or sulfinpyrazone from 1 January 2000 to 30 June 2006. Non-adherence was measured using the medication possession ratio (MPR) over the first year of therapy and defined as an MPR < 0.8. Descriptive statistics were calculated and logistic regression was used to estimate the strength of the association between patient characteristics and non-adherence.

Results

A total of 4,166 gout patients initiated ULDs; 97% received allopurinol. Median MPR for any ULD use was 0.68 (interquartile range (IQR) 0.64). Over half of the patients (56%) were non-adherent (MPR < 0.8). In adjusted analyses, predictors of poor adherence included younger age (odds ratio (OR) 2.43, 95% confidence interval (CI) 1.86 to 3.18 for ages <45 and OR 1.44, 95% CI 1.08 to 1.93 for ages 45 to 49), fewer comorbid conditions (OR 1.46, 95% CI 1.20 to 1.77), no provider visits for gout prior to urate-lowering drug initiation (OR 1.28, 95% CI 1.05 to 1.55), and use of non-steroidal anti-inflammatory drugs in the year prior to urate-lowering drug initiation (OR 1.15, 95% CI 1.00 to 1.31).

Conclusions

Non-adherence amongst gout patients initiating ULDs is exceedingly common, particularly in younger patients with less comorbidity and no provider visits for gout prior to ULD initiation. Providers should be aware of the magnitude of non-adherence with ULDs.

Regimen complexity and medication nonadherence in elderly patients

Objective:

To assess whether the number of daily administrations of individual drugs, as a measure of regimen complexity, contributes to the profile of an elderly patient who adheres poorly to the prescribed therapy.

Population:

Six hundred ninety patients over 64 years who were consecutively admitted to 11 acute medical care and three long term/rehabilitation wards in Italy.

Main outcome measure:

Self-reported adherence to drugs taken at home before admission was measured by a single question assessment for each listed drug supplemented with a latter question about the circumstances of the missed administration. For cognitively impaired patients the question was put to patients’ relatives or caregivers.

Methods:

A structured multidimensional assessment was performed to identify nonadherence and its potential correlates. Correlates of nonadherence were identified by multivariable logistic regression.

Results:

We recorded 44 cases (6.4%) of nonadherence to at least one drug. Being assisted by foreign caregivers (OR 2.17; 95% CI 1.02–4.63) and the use of at least one multiple daily dosing drug (OR 2.99; 95% CI 1.24–7.17) were significant independent correlates of medication nonadherence, while age, selected indexes of frailty and the cumulative number of prescribed drugs were not.

Conclusion:

Regimen complexity and type of assistance are independent correlates of medication nonadherence.

Improving compliance and persistence to adjuvant tamoxifen and aromatase inhibitor therapy

Better compliance and persistence with therapy are associated with improved patient outcomes. As more and more patients survive breast cancer, compliance with adjuvant therapy becomes increasingly important. In clinical trials, compliance with adjuvant endocrine therapy among women with breast cancer is usually high. Retrospective analyses of databases and medical records from clinical practice, insurance databases of prescription refills, and survey data show a significant decrease in persistence after 12 months of therapy. With ongoing therapy, a further decline in persistence of up to 50% has been reported. A consistent methodology is needed to measure patient behavior and identify patients who are not adhering to therapy. Promising strategies for enhancing adherence to treatment in clinical practice include improving access to health care, increasing patient satisfaction, managing side effects, patient education, and better communication between the patient and health care provider. Positive relationships between patients and their health care providers, and frequent monitoring and feedback, may be most effective. While the lack of conformity across studies in measuring makes cross-study comparisons difficult, this review evaluates the available data regarding compliance and persistence with adjuvant endocrine therapies for breast cancer (tamoxifen and aromatase inhibitors) and presents strategies for improving adherence.

Medication persistence over 2 years of follow-up in a cohort of early rheumatoid arthritis patients: associated factors and relationship with disease activity and with disability

Introduction

Aggressive treatment with disease-modifying antirheumatic drugs (DMARDs) plays a major role in improving early rheumatoid arthritis (RA) patient outcomes. Persistence and adherence with medication occurs variably (20% to 70%). The objectives of the study were to determine medication persistence (MP) in early RA patients over 13 consecutive visits each 2 months apart, to investigate the relationship between MP and disease activity, disability and structural damage, and to identify baseline prognosticators.

Methods

Charts from 75 patients of an early RA cohort were reviewed. At each visit, a rheumatologist interviewed patients regarding therapy, scored disease activity with the 28-joint disease activity score (DAS28) and disability with the health assessment questionnaire (HAQ), and recorded comorbidities and treatment. A complete medical history was obtained at baseline. MP was defined as the duration of time from initiation to discontinuation of at least one DMARD and/or corticosteroids for at least 1 week and was reported as a dichotomous variable at consecutive evaluations. Structural damage was defined by detection of new erosions on radiography. Descriptive statistics, Student's t test, the chi-squared test, and logistic regression analyses were used.

Results

The proportion of MP patients decreased from 98% at 2 months to 34% at 2 years. MP patients (n = 32) had similar DAS28 to non-MP patients (n = 53) at initial visits, lower DAS28 and greater DAS28 improvements at follow-ups (P ≤ 0.05 at visits 4, 6, 7 and 9) and reached sustained remission (≥ 3 consecutive visits with DAS28 < 2.6) more frequently (82.8% versus 46.5%, P = 0.003) and earlier (7.7 ± 4.6 versus 13.6 ± 5.7 months, P = 0.001) than non-MP patients. MP patients had similar baseline HAQ scores, but lower HAQ scores at follow-up (P ≤ 0.05 at visits 3, 5, 6, 7, 9, 10 and 13). More non-MP patients developed erosive disease than MP patients (26.8% versus 17.9%, P = 0.56). Older age at baseline was associated with therapy discontinuation (odds ratio = 1.1, 95% confidence interval = 1.007 to 1.103, P = 0.02).

Conclusions

Discontinuation of DMARDs was frequent and progressive in an early RA cohort. Patients with persistence on therapy were younger, had lower disease activity and disability during follow-up, and reached sustained remission more frequently and earlier than patients without it. MP should intentionally be evaluated during follow-up of early RA patients, as it seems to play a major role in outcome.

Racial differences in long-term adherence to oral antidiabetic drug therapy: a longitudinal cohort study

Background

Adherence to oral antidiabetic medications is often suboptimal. Adherence differences may contribute to health disparities for black diabetes patients, including higher microvascular event rates, greater complication-related disability, and earlier mortality.

Methods

In this longitudinal retrospective cohort study, we used 10 years of patient-level claims and electronic medical record data (1/1/1992–12/31/2001) to assess differences in short- and long-term adherence to oral antidiabetic medication among 1906 newly diagnosed adults with diabetes (26% black, 74% white) in a managed care setting in which all members have prescription drug coverage. Four main outcome measures included: (1) time from diabetes diagnosis until first prescription of oral antidiabetic medication; (2) primary adherence (time from first prescription to prescription fill); (3) time until discontinuation of oral antidiabetic medication from first prescription; and (4) long-term adherence (amount dispensed versus amount prescribed) over a 24-month follow-up from first oral antidiabetic medication prescription.

Results

Black patients were as likely as whites to initiate oral therapy and fill their first prescription, but experienced higher rates of medication discontinuation (HR: 1.8, 95% CI: 1.2, 2.7) and were less adherent over time. These black-white differences increased over the first six months of therapy but stabilized thereafter for patients who initiated on sulfonylureas. Significant black-white differences in adherence levels were constant throughout follow-up for patients initiated on metformin therapy.

Conclusion

Racial differences in adherence to oral antidiabetic drug therapy persist even with equal access to medication. Early and continued emphasis on adherence from initiation of therapy may reduce persistent racial differences in medication use and clinical outcomes.

Medication adherence, first episode duration, overall duration and time without therapy: the example of bisphosphonates

PURPOSE

We aimed to determine the duration of first episode of therapy and overall therapy as well as time without treatment for bisphosphonates.

METHODS

Data were extracted from Department of Veterans' Affairs (DVA) dataset for those with at least one dispensing for a bisphosphonate between April 2001 and April 2007. Episodes of use were determined as the number of treatment days between the first and last prescription plus 35 days once a dispensing gap of 105 days had been reached, or where no treatment gaps were recorded, the study end date. Kaplan-Meier analyses were undertaken for the first episode of use, overall duration and time without treatment.

RESULTS

When considering only the duration of first episode, median bisphosphonate use was 1.19 years. The median duration extended to 3.27 years when all episodes of use were considered. Overall, 52.0% of subjects reached at least 3 years of treatment and 66.5% of existing users had a duration of at least 3 years. Median time without treatment was 1.65 years. Overall, 81% of the cohort had enough medicine dispensed to be considered adherent throughout their duration of use.

CONCLUSION

Over 50% of subjects and 66% of existing users had duration consistent with the minimum recommended. Adherence within an episode was high. The focus for improving duration of bisphosphonate use should be on reducing the time without treatment, rather than adherence at the time of use. Studies assessing only the first episode of use in new users of medicines may underestimate duration.

Association of antiepileptic drug nonadherence with risk of seizures in adults with epilepsy

This study evaluated the potential effect of antiepileptic drug (AED) nonadherence on the risk of subsequent seizure. Retrospective insurance claims from the United States were analyzed. Inclusion criteria were: age 21-64 years, diagnosis of epilepsy or nonfebrile convulsions, 2 AED prescriptions, and insurance enrollment for 6 months pre- and 60 days post-AED initiation. Seizure was defined as a hospital or emergency admission associated with epilepsy or nonfebrile convulsions. Observation began 7 days post-drug initiation, ending with the first of the following: seizure, insurance disenrollment, or 365 days post-drug initiation. Adherence was measured using the medication possession ratio (MPR), with MPR <0.8 defining nonadherence. Seizure risk was assessed using an extended Cox proportional hazards model. Of 18,073 subjects identified, 2467 (14%) had 1 seizure. Mean follow-up was 133 days among subjects with event and 305 days for patients without event. Seizure risk was 21% higher among nonadherers (hazard ratio=1.205, P=0.0002) than adherers.

Prevalence and cost of nonadherence to antiepileptic drugs in elderly patients with epilepsy

Retrospective insurance claims from the United States were analyzed to assess nonadherence to antiepileptic drugs (AEDs) and the association between AED nonadherence, seizures, and health care costs in elderly persons with epilepsy. Inclusion criteria were: age 65, epilepsy diagnosis between 1 January 2000 and 31 June 2006, 2 AED prescriptions, and insurance enrollment for 6 months pre- and 12 months post-AED initiation. Adherence was evaluated using the medication possession ratio (MPR), with MPR<0.8 defining nonadherence. Per-patient outcomes were evaluated over 12 months post-AED initiation. Of 1278 patients identified, 41% were nonadherent. Seizure, defined by epilepsy-related inpatient or emergency department admission, occurred in 12.1% of nonadherers versus 8.2% of adherers (P=0.0212). Nonadherers had higher inpatient (+$872, P=0.001), emergency department (+$143, P=0.0008), other outpatient ancillary (+$1741, P=0.0081), and total health care (+$2674, P=0.0059) costs. AED adherence among elderly patients with epilepsy is suboptimal and associated with increased seizures and health care costs.

Pattern of intravenous bisphosphonate use in outpatient care in Germany

PURPOSE

Intravenous bisphosphonate therapy has recently been associated with the development of an osteonecrosis of the jaws (ONJ). If new adverse events have been linked to drugs, basic information on drug exposure in routine care is essential. The aim of this study was to investigate prevalence as well as duration and cumulative doses of intravenous bisphosphonate treatment.

METHODS

We analysed data of the statutory health insurance company Gmünder ErsatzKasse (GEK) over the years 2000-2006. We first estimated treatment prevalence in 2006. We further studied a cohort of new users of intravenous bisphosphonates who initiated treatment between 1 January 2001 and 31 December 2005. We used the Kaplan-Meier method to estimate the time to end of treatment (composite of discontinuation and death).

RESULTS

A total of 1024 patients received at least one dose of intravenous bisphosphonates in 2006. The most commonly prescribed agent was zoledronate (53.7%). After standardizing for sex and age, an estimated 0.1% of the German population would have been treated in 2006. Of 1259 new users in 2001-2005, an estimated 40% of men and 22% of women died within 12 months. The median treatment duration was 3.5 months in men and 5.7 months in women. This difference disappears when studying only survivors.

CONCLUSIONS

Although our study suggests that intravenous bisphosphonates were prescribed mainly for short durations, this result is strongly influenced by the fact that new users had a poor prognosis with a short life expectancy.

Impact of a prescription copayment increase on lipid-lowering medication adherence in veterans

BACKGROUND

In February 2002, the Department of Veterans Affairs (VA) increased copayments from $2 to $7 per 30-day drug supply of each medication for many veterans. We examined the impact of the copayment increase on lipid-lowering medication adherence.

METHODS AND RESULTS

This quasiexperimental study used electronic records of 5604 veterans receiving care at the Philadelphia VA Medical Center from November 1999 to April 2004. The all copayment group included veterans subject to copayments for all drugs with no annual cap. Veterans subject to copayments for drugs only if indicated for a non-service-connected condition with an annual cap of $840 for out-of-pocket costs made up the some copayment group. Veterans who remained copayment exempt formed a natural control group (no copayment group). Patients were identified as adherent if the proportion of days covered with lipid-lowering medications was > or =80%. Patients were identified as having a continuous gap if they had at least 1 continuous episode with no lipid-lowering medications for > or =90 days. A difference-in-difference approach compared changes in lipid-lowering medication adherence during the 24 months before and after copayment increase among veterans subject to the copayment change with those who were not. Adherence declined in all 3 groups after the copayment increase. However, the percentage of patients who were adherent (proportion of days covered > or =80%) declined significantly more in the all copayment (-19.2%) and some copayment (-19.3%) groups relative to the exempt group (-11.9%). The incidence of a continuous gap increased significantly at twice the rate in both copayment groups (all copayment group, 24.6%; some copayment group, 24.1%) as the exempt group (11.7%). Compared with the exempt group, the odds of having a continuous gap in the after relative to the before period were significantly higher in both the all copayment group (odds ratio, 3.04; 95% confidence interval, 2.29 to 4.03) and the some copayment group (odds ratio, 1.85; 95% confidence interval, 1.43 to 2.40). Similar results were seen in subgroups of patients at high risk for coronary heart disease, high medication users, and elderly veterans.

CONCLUSIONS

The copayment increase adversely affected lipid-lowering medication adherence among veterans, including those at high coronary heart disease risk.

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.

Two Pharmacy Interventions to Improve Refill Persistence for Chronic Disease Medications

BACKGROUND

Despite the proven effectiveness of many medications for chronic diseases, many patients do not refill their prescriptions in the required timeframe.

OBJECTIVE

Compare the effectiveness of 3 pharmacist strategies to decrease time to refill of prescriptions for common chronic diseases. RESEARCH DESIGN/SUBJECTS: A randomized, controlled clinical trial with patients as the unit of randomization. Nine pharmacies within a medium-sized grocery store chain in South Carolina were included, representing urban, suburban, and rural areas and patients from a variety of socioeconomic backgrounds. Patients (n = 3048) overdue for refills for selected medications were randomized into 1 of 3 treatment arms: (1) pharmacist contact with the patient via telephone, (2) pharmacist contact with the patient's prescribing physician via facsimile, and (3) usual care.

MEASURES

The primary outcome was the number of days from their recommended refill date until the patient filled a prescription for any medication relevant to his/her chronic disease. Prescription refill data were obtained routinely from the pharmacy district office's centralized database. Patient disposition codes were obtained by pharmacy employees. An intent-to-treat approach was used for all analyses.

RESULTS

There were no significant differences by treatment arm in the study outcomes.

CONCLUSIONS

Neither of the interventions is more effective than usual care at improving persistence of prescription refills for chronic diseases in overdue patients.

Gastroprotection among new chronic users of non-steroidal anti-inflammatory drugs: a study of utilization and adherence in The Netherlands

OBJECTIVE

To describe the use of gastroprotection (GP) among new chronic users of NSAIDs in the Netherlands by gastrointestinal (GI) risk factor (RF) score.

METHODS

Data for this retrospective follow-up study were extracted from the PHARMO database. We selected new chronic users of COX-2 inhibitors (coxibs) or traditional NSAIDs (tNSAIDs) between 1st January 2000 and 31st December 2004. GP strategies were defined as: use of proton pump inhibitors (PPI), coxibs or both. GI RF score at index date was based on: history of GI drug use, high dose of NSAIDs, age > 60 years, use of corticosteroids/anticoagulants/SSRIs, rheumatoid arthritis, heart failure or diabetes, with each condition accounting for one factor. Switching was assessed among those with > or = 1 GI RF during the first year of follow-up.

RESULTS

Among 58,770 new chronic NSAID users at index date, 80% used tNSAIDs alone, 8% used tNSAID + PPI, 10% used a coxib alone and 2% used coxib + PPI. Mean (SD) number of GI RF among these groups was 1.6 (2.1), 3.1 (1.3), 1.5 (1.5) and 2.8 (1.3), respectively. Among 48 390 patients (82.3%) with a GI RF score of > or = 1, 20.9% used a GP strategy, this increased with number of GI RFs. Within the first year, 5.3% (n = 2067) and 4.8%(n = 1 843) of tNSAID users with > or = 1 GI RF switched to tNSAID+PPI and coxib alone, respectively.

CONCLUSIONS

Gastroprotection in users of tNSAIDs was inadequate. Over 80% of NSAID users with > or = 1 GI RF did not receive any gastroprotection, and even when prescribed, a PPI is used only half the time. More research should show if gastroprotection was used for prevention.

Gastroprotection in patients prescribed non-selective NSAIDs, and the risk of related hospitalization

OBJECTIVE

To assess co-prescription of gastroprotective agents (GPAs) for non-selective NSAID (nsNSAID)-treated patients in UK primary care, and the rate of gastrointestinal (GI)-related hospitalizations occurring with varying levels of GPA use in patients at high Gl risk.

RESEARCH DESIGN AND METHODS

A retrospective, observational study was conducted using the DIN-LINK UK primary care database, on patients prescribed nsNSAIDs alone or concomitantly with GPAs between September 2003 and August 2005. Patients were stratified by GI risk, frequency of nsNSAID use and level of GPA use. Rates and odds ratios of GI-related hospitalizations were calculated for high GI-risk patients.

RESULTS

In August 2005, 26 371 patients with nsNSAID prescriptions were identified, of whom 55% were frequent users. In the overall and frequent nsNSAID-user populations, 74% and 71%, respectively, were co-prescribed none or few GPAs (0-19% level of use), and only 18% and 20%, respectively, received complete gastroprotection. GI risk factors were identified in 76% of all patients. Overall, 70% of patients with serious co-morbidity, 44% with GI event history, and 56% of aspirin users received little or no gastroprotection (0-19%). Data for previous months of the analysis period were similar. In patients with a GI-event history, based on data over the 2-year study period, hospitalization rates ranged from 2.4% (with full gastroprotection) to 8.0% (20-39% GPA use). Odds of a GI-related hospitalization were up to 3.5 times higher with low GPA use.

CONCLUSION

This study revealed low levels of GPA co-prescription for nsNSAID users in UK primary care, even among high-risk patients. Lower levels of GPA co-therapy were associated with increasing rates of GI-related hospitalization.

An empirical basis for standardizing adherence measures derived from administrative claims data among diabetic patients

OBJECTIVE

To compare the predictive validity of 8 different adherence measures by studying the variability explained between each measure and 2 outcome measures: hospitalization episodes and total nonpharmacy cost among Medicaid eligible persons diagnosed with diabetes.

RESEARCH DESIGN

This study was a retrospective analysis of the Arkansas Medicaid administrative claims data from January 2000 to December 2006.

SUBJECTS

Diabetic (ICD-9-CM = 250.0 x - 250.9 x, where x = 0 or 2) patients were identified in the recruitment period July 2000 through April 2004. Patients had to be >or=18 years old and have at least 2 prescription fills in the index period for an oral antidiabetic drug.

MEASURES

: Adherence rates to oral antidiabetic therapy were contrasted using the following 8 measures; including the medication possession ratio (MPR), proportion of days covered (PDC), refill compliance rate (RCR), compliance ratio (CR), medication possession ratio, modified (MPRm), continuous measure of medication gaps (CMG), and continuous multiple interval measure of oversupply (CMOS and continuous, single interval measure of medication acquisition (CSA). Multivariate and univariate linear and logistic regression models were used to prospectively predict nonpharmacy costs and hospitalizations in the follow-up year.

RESULTS

A total of 4943 diabetic patients were studied. In predicting any cause hospitalization, univariate models with PDC and CMG had the highest predictive validity (C-statistic: 0.544). Multivariate models with MPR, PDC, CMG or continuous multiple interval measure of oversupply (CMOS) as adherence measures had the highest C-statistics of 0.701 in predicting diabetes specific hospitalizations. None of the adherence measures were significantly associated with nonpharmacy cost.

CONCLUSIONS

MPR and PDC had the highest predictive validity for hospitalization episodes. These 2 measures should be considered first when selecting among adherence measures when using administrative prescription claims data.

Persistence of asthma medication use in preschool children

OBJECTIVE

In young children with asthmatic symptoms diagnostic difficulties lead to use of trials of asthma medication as a diagnostic tool. Our aim is to quantify the persistent use of asthma medication, initiated in the first year of life and identify determinants of this persistent use.

PATIENTS AND METHODS

We identified 165 children within the PIAMA (Prevention and Incidence of Asthma and Mite Allergy) birth cohort who used asthma medication before the age of one. Persistent use was investigated during three years after the first prescription. A Cox regression analysis was performed to identify factors associated with persistent use.

RESULTS

A total of 58.8% of children continued using asthma medication after the first prescription and 10.3% continued during three years. Children with doctor-diagnosed asthma (Hazard ratio of discontinuation (HR)=0.64, 95% CI: 0.45-0.91) or prescribed inhaled corticosteroids in the first year of life (HR of discontinuation=0.59, 95% CI: 0.40-0.86) were 1.6-1.7 times more likely to continue using asthma medication.

CONCLUSIONS

Persistence of asthma medication, prescribed in the first year of life is very low and is positively associated with doctor-diagnosed asthma and use of inhaled corticosteroids. Characterizing persistent users of asthma medication is important to understand prescribing of asthma medication in this age group.

Comparison of drug adherence rates among patients with seven different medical conditions

STUDY OBJECTIVE

To compare drug adherence rates among patients with gout, hypercholesterolemia, hypertension, hypothyroidism, osteoporosis, seizure disorders, and type 2 diabetes mellitus by using a standardized approach.

DESIGN

Longitudinal study.

DATA SOURCE

Health care claims data from 2001-2004.

PATIENTS

A total of 706,032 adults aged 18 years or older with at least one of the seven medical conditions and with incident use of drug therapy for that condition.

MEASUREMENTS AND MAIN RESULTS

Drug adherence was measured as the sum of the days' supply of drug therapy over the first year observed. Covariates were age, sex, geographic residence, type of health plan, and a comorbidity score calculated by using the Hierarchical Condition Categories risk adjuster. Bivariate statistics and stratification analyses were used to assess unadjusted means and frequency distributions. Sample sizes ranged from 4984 subjects for seizure disorders to 457,395 for hypertension. During the first year of drug therapy, 72.3% of individuals with hypertension achieved adherence rates of 80% or better compared with 68.4%, 65.4%, 60.8%, 54.6%, 51.2%, or 36.8% for those with hypothyroidism, type 2 diabetes, seizure disorders, hypercholesterolemia, osteoporosis, or gout, respectively. Age younger than 60 years was associated with lower adherence across all diseases except seizure disorders. Comorbidity burden and adherence varied by disease. As comorbidity increased, adherence among subjects with osteoporosis decreased, whereas adherence among those with hypertension, hypercholesterolemia, or gout increased. Add-on drug therapies and previous experience with taking drugs for the condition increased adherence among subjects with hypertension, type 2 diabetes, hypothyroidism, or seizure disorders but not the other conditions.

CONCLUSION

This uniform comparison of drug adherence revealed modest variation across six of seven diseases, with the outlier condition being gout.

Medication adherence and racial differences in A1C control

OBJECTIVE

The purpose of this study was to examine medication adherence and other self-management practices as potential determinants of higher glycemic risk among black relative to white patients.

RESEARCH DESIGN AND METHODS

We used a retrospective, longitudinal repeated-measures design to model the contribution of medication adherence to black-white differences in A1C among type 2 diabetic patients at a large multispecialty group practice. We identified 1,806 adult (aged >/=18 at diagnosis) patients (467 black and 1,339 white) with newly initiated oral hypoglycemic therapy between 1 December 1994 and 31 December 2000. Race was identified using an electronic medical record and patient self-report. Baseline was defined as the 13 months preceding and included the month of therapy initiation. All patients were required to have at least 12 months of follow-up.

RESULTS

At initiation of therapy, black patients had higher average A1C values compared with whites (9.8 vs. 8.9, a difference of 0.88; P < 0.0001). Blacks had lower average medication adherence during the first year of therapy (72 vs. 78%; P < 0.0001). Although more frequent medication refills were associated with lower average A1C values, adjustment for adherence did not eliminate the black-white gap.

CONCLUSIONS

We found persistent racial differences in A1C that were not explained by differences in medication adherence. Our findings suggest that targeting medication adherence alone is unlikely to reduce disparities in glycemic control in this setting. Further research is needed to explore possible genetic and environmental determinants of higher A1C among blacks at diagnosis, which may represent a critical period for more intensive intervention.

Are patients reliable when self-reporting medication use? Validation of structured drug interviews and home visits by drug analysis and prescription data in acutely hospitalized patients

The medication history among hospitalized patients often relies on patients' self-reports due to insufficient communication between health care professionals. The aim of the present study was to estimate the reliability of patients' self-reported medication use. Five hundred patients admitted to an acute medical department at a Danish university hospital were interviewed on the day of admission about their recent medication use. Blood samples drawn immediately after admission were screened for contents of 5 drugs (digoxin, bendroflumethiazide, amlodipine, simvastatin, glimepiride), and the results were compared to the patients' self-reported medication history. Information on prescribed drugs dispensed from any Danish pharmacy was collected from nationwide real-time pharmacy records. The authors performed home visits in a subgroup of 115 patients 4 weeks after their discharge. Stored drugs were inspected, and patients were interviewed about their drug use. Additional blood samples were drawn for drug analysis. The median age of included patients was 72 years, and 298 patients (60%) were women. Patients reported use of 3 (median) prescription-only medications (range, 0-14) during the structured interview. The congruence between self-report and drug analysis was high for all 5 drugs measured (all kappa >0.8). However, 9 patients (2%) reported use of drugs that were not detected in their blood samples. In 29 patients (6%), the blood samples contained drugs not reported during the structured interview, but 14 of these drugs were registered in either hospital files or pharmacy records. Overall, the sensitivity of information from hospital files, structured interviews, and pharmacy records in identifying drug users was 87% to 93%, with no significant differences between methods. In conclusion, patients' self-reports are reliable when estimating recent use of cardiovascular and antidiabetic drugs.

Prevalence and cost of nonadherence with antiepileptic drugs in an adult managed care population

PURPOSE

This study assessed the extent of refill nonadherence with antiepileptic drugs (AEDs) and the potential association between AED nonadherence and health care costs in an adult-managed care population.

METHODS

Retrospective claims from the PharMetrics database were analyzed. Inclusion criteria were: age > or =21, epilepsy diagnosis between January 01, 2000 and March 12, 2005, > or =2 AED prescriptions, and continuous health plan enrollment for > or =6 months prior to and > or =12 months following AED initiation. Adherence was evaluated using the medication possession ratio (MPR). Patients with an MPR <0.8 were classified as nonadherent. Multivariate regression was used to assess the effect of AED nonadherence on annualized cost outcomes. Regression covariates included patient demographics, Charlson Comorbidity Index (CCI), and follow-up duration.

RESULTS

Among patients meeting all inclusion criteria (N = 10,892), 58% were female, mean age was 44 years, mean CCI was 0.94, and mean follow-up was 27 months. Mean MPR was 0.78 and 39% of patients were nonadherent. AED nonadherence was associated with an increased likelihood of hospitalization (odds ratio [OR]= 1.110, p = 0.013) and emergency room (ER) admission (OR = 1.479, p < 0.0001), as well as increased inpatient and ER costs of $1,799 and $260 (both p = 0.001), respectively, per patient per year. Outpatient and other ancillary costs were not significantly affected by nonadherence. A large net positive effect of nonadherence on total annual health care costs remained (+$1,466, p = 0.034) despite an offset from reduced prescription drug intake.

DISCUSSION

Adherence with AEDs among adult epilepsy patients is suboptimal and nonadherence appears to be associated with increased health care costs. Efforts to promote AED adherence may lead to cost savings for managed care systems.

Assessment of Adherence to and Persistence on Disease-Modifying Antirheumatic Drugs (DMARDs) in Patients With Rheumatoid Arthritis

OBJECTIVE

Biologic disease-modifying antirheumatic drugs (DMARDs) are efficacious for treating rheumatoid arthritis (RA). However, measurements of relative effectiveness, including treatment adherence and persistence, are lacking. We evaluated adherence and persistence during new episodes of use of traditional and biologic DMARDs.

METHODS

Using Tennessee Medicaid databases (1995-2004), we assembled a retrospective cohort of patients diagnosed with RA, and identified new episodes of use for 12 DMARD regimens. We evaluated persistence through survival analyses, and adherence within episodes through the medication possession ratio. A risk score was included in the analyses to account for measured confounders.

RESULTS

We identified 14,932 patients with RA; 6018 patients had 10,547 episodes of new use of DMARDs. Considering methotrexate as the reference and after adjustment for measured confounders, episodes of new use of sulfasalazine [adjusted hazard ratio (aHR) = 1.59; 95% confidence interval (CI) = 1.47-1.72] and infliximab alone (aHR = 1.37, 95% CI = 1.09-1.73) were more likely to be discontinued; and new episodes of etanercept (aHR = 0.82, 95% CI = 0.73-0.92) and methotrexate + adalimumab (aHR = 0.63, 95% CI = 0.48-0.84) were less likely to be discontinued. Compared with methotrexate, adherence was higher for leflunomide, infliximab, etanercept, and adalimumab and lower for sulfasalazine and all combined therapies.

CONCLUSIONS

We developed an approach to assess persistence on and adherence to the most common DMARD therapies. In this large cohort, persistence and adherence to leflunomide and most biologic DMARD therapies were at least comparable to methotrexate. Adherence was lower for sulfasalazine and all combined therapies.

How expensive is antipsychotic polypharmacy? Experience from five US state Medicaid programs

OBJECTIVE

To characterize healthcare costs associated with antipsychotic polypharmacy and to investigate predictors of high-cost patients.

METHODS

A retrospective cohort study using Medicaid claims data from California, Nebraska, Oregon, Utah, and Wyoming evaluated 55 383 fee-for-service patients with antipsychotic prescriptions between 1998 and 2002. Polypharmacy was defined as initiating multiple antipsychotic drugs or concomitant antipsychotic therapy (>or=60 days). Healthcare costs (drug and non-drug) were summed for 365 days following index antipsychotic claim. Adjusted mean costs were compared to antipsychotic monotherapy. Logistic regression was performed to identify predictors of high-cost patients (top quintile) with regard to patient age, gender, race/ethnicity, mental disorders, hospitalization, index antipsychotic, concomitant psychotropic drugs, and polypharmacy.

RESULTS

The average annual prevalence of antipsychotic polypharmacy was 6%. 70-80% of total healthcare expenditures for polypharmacy patients were drug-related. Polypharmacy was associated with significantly higher drug expenditures ($1716-2079) in the year following drug initiation than monotherapy even after adjusting for case mix and index antipsychotic (p < 0.05). Differences in non-drug expenditures versus monotherapy were smaller and varied by state ranging from a $77 increase in California (p < 0.001) to a $211 savings in Utah (p = 0.02). In California, polypharmacy alone (OR = 2.69; 95% CI: 2.30-3.16) or in combination with concomitant psychotropics (OR = 6.26; 95% CI: 5.51-7.11) was associated with greater likelihood of being a high-cost patient than monotherapy.

CONCLUSIONS

Cost savings from limiting antipsychotic polypharmacy could be significant. Caution must be taken in ensuring reductions in polypharmacy do not lead to unintended consequences or shift care to more costly alternatives. Study limitations, including the known shortcomings of claims data and differences across state Medicaid programs, should be considered when interpreting the results of this or any multi-state study.

Clinical evaluation of IDAS II, a new electronic device enabling drug adherence monitoring

OBJECTIVE

The goal of this study was to evaluate clinically the acceptability of the IDAS II (Intelligent Drug Administration System), a new electronic device that enables drug adherence monitoring.

METHODS

IDAS II was compared to another electronic monitor, the Medication Event Monitoring System (MEMS) in a randomised two-way cross-over study involving 24 hypertensive patients treated with irbesartan. Patients used each device for 2 months. The main parameter of evaluation was the patients' opinion on both devices. Rates of adherence and blood pressure were also assessed.

RESULTS

Most patients considered both devices to be reliable reminders (IDAS II: 75%;MEMS: 84%, p = ns). Ten patients (42%) preferred the MEMS, while 11 (46%) preferred the IDAS II; three (12%) expressed no preference. Patients found the MEMS device easier to use than the IDAS device (p < 0.001) but appreciated the IDAS blister packs better than the MEMS bulk packaging (p < 0.01). Over the 4-month period, the median "taking adherence" was excellent (99.2%) and comparable with both devices. However, the regularity of drug intake timing was higher with the IDAS II (p < 0.01).

CONCLUSION

IDAS II, a new electronic device enabling drug adherence monitoring without reconditioning of the drugs appears to be a well-accepted device. Overall, practicability and acceptability of the IDAS II and the MEMS device were similar. Thus, IDAS II could be a useful tool for the management of long-term therapies.

Prevalence, utilization patterns, and predictors of antipsychotic polypharmacy: experience in a multistate Medicaid population, 1998-2003

OBJECTIVES

This study was conducted to estimate the prevalence of antipsychotic polypharmacy among fee-for service state Medicaid beneficiaries initiating antipsychotic drug therapy and to investigate psychiatric and demographic predictors of such polypharmacy.

METHODS

This was a retrospective cohort study employing Medicaid claims data from California, Nebraska, Oregon, Utah, and Wyoming for patients who filled >1 antipsychotic prescription between 1998 and 2003 and who were continuously eligible for benefits from 180 days before to 1 year after the index antipsychotic claim. Antipsychotic Polypharmacy was defined as initiation of multiple antipsychotic medications or at least 60 consecutive days of concomitant antipsychotic medication overlapping the index antipsychotic prescription at any time during the 365 days after the index drug claim. Primary and secondary diagnosis codes (International Classification of Diseases, Ninth Revision, Clinical Modification) were used to identify patients with mental disorders and mental health-related hospitalizations. Multivariate logistic regression, with adjustment for sex, age, race/ethnicity, state, mental health diagnoses, hospitalization, year, and type of index antipsychotic, was performed to identify predictors of polypharmacy. A multivariate Cox proportional hazards model was used to compare the cumulative incidence of polypharmacy by index antipsychotic drug.

RESULTS

The study cohort consisted of 55,481 individuals with > or =1 prescription claim for an antipsychotic drug. The mean prevalence of long-term antipsychotic polypharmacy in the year after initiating antipsychotic medication was 6.4%. Approximately half of those with polypharmacy were started on multiple antipsychotic drugs and half were started on monotherapy but received > or =2 antipsychotic drugs concomitantly in the year after drug initiation. Among the stronger predictors of polypharmacy were a diagnosis of schizophrenia (odds ratio [OR] = 2.95; 95% Cl, 2.43-3.58), recent mental health hospitalization (OR = 1.17; 95% Cl, 1.02-1.33), and the number of mental health diagnoses (OR = 1.07 per diagnosis; 95% CI, 1.06-1.08). Polypharmacy was more likely among male than female patients (OR = 1.26; 95% Cl, 114-1.39) and among those between the ages of 18 and 24 years. The cumulative incidence of polypharmacy was greater among patients initiating clozapine compared with those initiating other antipsychotics (P < 0.001).

CONCLUSIONS

In these fee-for-service Medicaid beneficiaries from 5 states, the prevalence of chronic antipsychotic polypharmacy was low in the year after the initiation of therapy. Polypharmacy was more common in patients with indicators of more severe mental illness.

Early discontinuation of tamoxifen: a lesson for oncologists

BACKGROUND

Five years of treatment provides the optimum duration of tamoxifen therapy for the prevention of breast cancer recurrence and mortality. Durations of adjuvant tamoxifen therapy less than 5 years are associated with poorer outcomes for breast cancer patients. The purpose of the study was to assess rates of tamoxifen nonpersistence (early discontinuation) in women aged 35 years or older using prescription refill data from a national prescribing database.

METHODS

A cohort of 2816 women commencing tamoxifen as initial hormonal therapy was identified between January 2001 and January 2004. The cumulative tamoxifen persistence rate was calculated for these women and the relation between nonpersistence and clinical and demographic variables assessed.

RESULTS

Within 1 year of commencing treatment the cumulative tamoxifen nonpersistence rate was 22.1%. This is twice the rate of treatment discontinuation observed in other studies by this time. By the end of follow-up at 3.5 years, the cumulative nonpersistence rate had increased to 35.2%. Determinants of nonpersistence identified included age and a history of antidepressant use.

CONCLUSIONS

The rate of nonpersistence with tamoxifen therapy is higher than previously reported. This study demonstrates that persistence with tamoxifen cannot be assumed and raises concerns about persistence with other oral hormonal therapies for breast cancer and oral antineoplastics in general. Oncologists need to identify those at risk of nonpersistence and develop strategies to combat this barrier to treatment success.

Adherence to Statin Therapy Under Drug Cost Sharing in Patients With and Without Acute Myocardial Infarction

Background— As medication spending grows, Medicare Part D will need to adapt its coverage policies according to emerging evidence from a variety of insurance policies. We sought to evaluate the consequences of copayment and coinsurance policies on the initiation of statin therapy after acute myocardial infarction and adherence to therapy in statin initiators using a natural experiment of all British Columbia residents aged 66 years and older.

Methods and Results— Three consecutive cohorts that included all patients who began statin therapy during full drug coverage (2001), coverage with a $10 or $25 copay (2002), and coverage with a 25% coinsurance benefit (2003–2004) were followed up with linked healthcare utilization data (n=51 561). Follow-up of cohorts was 9 months after each policy change. Adherence to statin therapy was defined as ≥80% of days covered. Relative to full-coverage policies, adherence to new statin therapy was significantly reduced, from 55.8% to 50.5%, under a fixed copayment policy (−5.4% points; 95% CI, −6.4% to −4.4%) and the subsequent coinsurance policy (−5.4% points; 95% CI, −6.3% to −4.4%). An uninterrupted increase in the proportion of patients initiating statin therapy after an acute myocardial infarction (1.7% points per quarter) was observed over the study period, similar to a Pennsylvania control population with full coverage. Sudden changes to full out-of-pocket spending, similar to Medicare’s Part D “doughnut hole,” almost doubled the risk of stopping statins (adjusted odds ratio, 1.94, 95% CI, 1.82 to 2.08).

Conclusions— Fixed patient copayment and coinsurance policies have negative effects on adherence to statin lipid-lowering drug therapy but not on their initiation after myocardial infarction.

Compliance with refilling prescriptions for atypical antipsychotic agents and its association with the risks for hospitalization, suicide, and death in patients with schizophrenia in Quebec and Saskatchewan: a retrospective database study

OBJECTIVE

The objective of this analysis was to describe the patterns of compliance with atypical antipsychotics among patients with schizophrenia in actual practice in 2 Canadian provinces and to examine the relation between degrees of compliance and the risks of hospitalization, suicide, and death.

METHODS

Adults with a diagnosis of schizophrenia who filled at least 1 prescription for risperidone, olanzapine, or quetiapine were identified in the Quebec public prescription drug insurance plan database (from July 1, 2001, to December 31, 2004) and the Saskatchewan Health database (from January 1, 1999, to December 31, 2003). Compliance was assessed based on the medication possession ratio, which was estimated as the proportion of days for which medication was available over each month of follow-up (> or = 80% = good compliance; 50%-79% = moderate compliance; < 50% = poor compliance). The association between the early and long-term effects of compliance and the risks of hospitalization, suicide, and death were examined using Cox regression, with adjustment for baseline age, sex, and use of antidepressants, sedatives, and lithium (Quebec only).

RESULTS

respective 41,754 and 3291 patients were identified from the Quebec and Saskatchewan databases. Approximately half of the patients in each cohort were male and were aged < 45 years. Many patients had good compliance over the full follow-up period (Quebec, 61%; Saskatchewan, 45%); however, poor compliance was seen in 23% of patients from Quebec and 34% of those from Saskatchewan. Compared with poor compliance, the long-term effect of good compliance was associated with a significantly decreased risk of all-cause hospitalization (Quebec: adjusted hazard ratio [HR] = 0.60; 95% CI, 0.57-0.64; Saskatchewan: adjusted HR = 0.81; 95% CI, 0.69-0.95) and psychosis-related hospitalization (Quebec: adjusted HR = 0.37; 95% Cl, 0.34-0.40; Saskatchewan: adjusted HR = 0.45; 95% CI, 0.32-0.64). The Quebec data also indicated a significant association between good versus poor compliance and a decreased risk of death (adjusted HR = 0.58; 95% CI, 0.51-0.66) and suicide (adjusted HR = 0.68; 95% CI, 0.55-0.84) that was not observed in Saskatchewan.

CONCLUSION

In this retrospective analysis of patients with schizophrenia in Quebec and Saskatchewan, good compliance with atypical antipsychotic medications was associated with substantial reductions in the risk for all-cause and psychosis-related hospitalizations.

Antihypertensive medication adherence in the Department of Veterans Affairs

PURPOSE

Adherence measures the extent to which patients take medications as prescribed by their health care provider. The control of hypertension is dependent on medication adherence and may vary on the basis of antihypertensive medication class and other factors.

METHODS

The Department of Veterans Affairs' automated pharmacy database captures pharmacy medication use; International Classification of Diseases, 9th Revision, diagnostic codes; and laboratory and patient demographic data on a monthly basis. Hypertensive patients who used thiazide diuretics, beta-blockers, angiotensin-converting enzyme inhibitors, angiotensin receptor blockers, calcium channel antagonists, and alpha-blockers from July 2002 to December 2003 were studied. The first date of prescription filling for each patient within the date range was the index date from which fill and refill dates were collected for up to 18 months to calculate medication possession ratios and days out of medication ratios. Patients were categorized as adherent if the medication possession ratio was 80% or greater. Logistic regression was used to study the association of medication class, age, gender, ethnicity, Veterans Affairs facility, and co-diagnosis with diabetes, schizophrenia/psychosis, depression, and dementia with medication adherence.

RESULTS

We studied 40,492 hypertensive patients taking at least one antihypertensive drug class. The average age per class ranged from 67.4 to 72.9 years; 96% were male; and 51% were white, 8% were African-American, 4% were Asian-American, and 3% were Hispanic. Unadjusted adherence rates based on the medication possession ratio ranged from 78.3% for thiazide diuretics to 83.6% for angiotensin receptor blockers (P<.001). The number of medications (either total or antihypertensive) and age were independent predictors of better adherence. Black ethnicity and depression were associated with worse adherence.

CONCLUSIONS

Adherence rates with all antihypertensive medications were high. Although there were statistical differences by drug class, these differences were small. Ethnicity and depression identified groups that might benefit from programs to improve adherence.