Publications

2010
Chan DC, Shrank WH, Cutler D, Jan S, Fischer MA, Liu J, Avorn J, Solomon D, Brookhart MA, Choudhry NK. Patient, physician, and payment predictors of statin adherence [Internet]. Medical Care 2010;48:196-202. Publisher's VersionAbstract

BACKGROUND:: Although many patient, physician, and payment predictors of adherence have been described, knowledge of their relative strength and overall ability to explain adherence is limited. OBJECTIVES:: To measure the contributions of patient, physician, and payment predictors in explaining adherence to statins. RESEARCH DESIGN:: Retrospective cohort study using administrative data. SUBJECTS:: A total of 14,257 patients insured by Horizon Blue Cross Blue Shield of New Jersey who were newly prescribed a statin cholesterol-lowering medication. MEASURES:: Adherence to statin medication was measured during the year after the initial prescription, based on proportion of days covered. The impact of patient, physician, and payment predictors of adherence were evaluated using multivariate logistic regression. The explanatory power of these models was evaluated with C statistics, a measure of the goodness of fit. RESULTS:: Overall, 36.4% of patients were fully adherent. Older patient age, male gender, lower neighborhood percent black composition, higher median income, and fewer number of emergency department visits were significant patient predictors of adherence. Having a statin prescribed by a cardiologist, a patient's primary care physician, or a US medical graduate were significant physician predictors of adherence. Lower copayments also predicted adherence. All of our models had low explanatory power. Multivariate models including patient covariates only had greater explanatory power (C = 0.613) than models with physician variables only (C = 0.566) or copayments only (C = 0.543). A fully specified model had only slightly more explanatory power (C = 0.633) than the model with patient characteristics alone. CONCLUSIONS:: Despite relatively comprehensive claims data on patients, physicians, and out-of-pocket costs, our overall ability to explain adherence remains poor. Administrative data likely do not capture many complex mechanisms underlying adherence.

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Cutrona SL, Choudhry NK, Stedman M, Servi A, Liberman JN, Brennan T, Fischer MA, Brookhart MA, Shrank WH. Physician effectiveness in interventions to improve cardiovascular medication adherence: a systematic review [Internet]. Journal of General Internal Medicine 2010;25:1090-6. Publisher's VersionAbstract

BACKGROUND: Medications for the prevention and treatment of cardiovascular disease save lives but adherence is often inadequate. The optimal role for physicians in improving adherence remains unclear. OBJECTIVE: Using existing evidence, we set the goal of evaluating the physician's role in improving medication adherence. DESIGN: We conducted systematic searches of English-language peer-reviewed publications in MEDLINE and EMBASE from 1966 through 12/31/2008. SUBJECTS AND INTERVENTIONS: We selected randomized controlled trials of interventions to improve adherence to medications used for preventing or treating cardiovascular disease or diabetes. MAIN MEASURES: Articles were classified as either (1) physician "active"-a physician participated in designing or implementing the intervention; (2) physician "passive"-physicians treating intervention group patients received patient adherence information while physicians treating controls did not; or (3) physicians noninvolved. We also identified studies in which healthcare professionals helped deliver the intervention. We did a meta-analysis of the studies involving healthcare professionals to determine aggregate Cohen's D effect sizes (ES). KEY RESULTS: We identified 6,550 articles; 168 were reviewed in full, 82 met inclusion criteria. The majority of all studies (88.9%) showed improved adherence. Physician noninvolved studies were more likely (35.0% of studies) to show a medium or large effect on adherence compared to physician-involved studies (31.3%). Among interventions requiring a healthcare professional, physician-noninvolved interventions were more effective (ES 0.47; 95% CI 0.38-0.56) than physician-involved interventions (ES 0.25; 95% CI 0.21-0.29; p < 0.001). Among physician-involved interventions, physician-passive interventions were marginally more effective (ES 0.29; 95% CI 0.22-0.36) than physician-active interventions (ES 0.23; 95% CI 0.17-0.28; p = 0.2). CONCLUSIONS: Adherence interventions utilizing non-physician healthcare professionals are effective in improving cardiovascular medication adherence, but further study is needed to identify the optimal role for physicians.

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Choudhry NK. Relationship between high cost sharing and adverse outcomes: a truism that's tough to prove [Internet]. American Journal of Managed Care 2010;16:287-9. Publisher's Version PDF
Shrank WH, Choudhry NK, Agnew-Blais J, Federman AD, Liberman JN, Liu J, Kesselheim AS, Brookhart MA, Fischer MA. State generic substitution laws can lower drug outlays under medicaid [Internet]. Health Affairs (Millwood) 2010;29:1383-90. Publisher's VersionAbstract

To stem the rising costs of medications provided to patients enrolled in Medicaid, states have implemented varying policies about generic substitution. These policies differ in the extent to which pharmacists or patients can influence which medications they choose. Using national Medicaid data, we evaluated the relationship between different generic substitution policies and the use of generic simvastatin, a cholesterol-lowering drug, after the patent for the brand-name equivalent, Zocor, expired. States that implemented policies requiring patients' consent prior to generic substitution experienced rates of substitution that were 25 percent lower than those of states that did not require patient consent. By eliminating patient consent requirements, state Medicaid programs could expect to save more than $100 million in coverage for three top-selling medications that are nearing patent expiration. Although these consent requirements are probably intended to increase patient autonomy, policy makers should consider the sizable opportunity costs.

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Parikh S, Shrank WH, Mogun H, Choudhry NK. Statin Utilization in Nursing Home Patients after Cardiac Hospitalization [Internet]. Journal of General Internal Medicine 2010; Publisher's VersionAbstract

BACKGROUND: Coronary artery disease (CAD) is highly prevalent in nursing home residents and is associated with a substantial clinical and economic burden. Statins reduce mortality and hospitalization rates in older patients with CAD. OBJECTIVES: To assess rates and predictors of statin use among high-risk patients with symptomatic coronary artery disease (CAD) admitted to nursing homes after acute cardiac hospitalization. DESIGN: Cohort study. PARTICIPANTS: Medicare beneficiaries enrolled in either a state-run drug assistance program or Medicaid in nursing homes in New Jersey from 1994 through 2005. MEASUREMENTS: Statin utilization within 60 days of nursing home admission was determined for patients recently hospitalized with symptomatic CAD in whom statins are indicated consisting of those with: acute coronary syndrome (ACS) without revascularization, ACS with revascularization and congestive heart failure (CHF) with revascularization. Predictors of statin use were evaluated with multivariate logistic regression models. RESULTS: While statin use over the 11-year period increased from 1.2% to 31.8%, overall utilization was very low. Predictors of greater statin use included prior cardiac hospitalization [odds ratio (OR) 1.32, 95% confidence interval (95% CI) 1.13 to 1.57], prior statin use (OR 6.92, 95% CI 5.86 to 8.82) and receipt of a concurrent cardiac medication (range of odds ratios, 2.36-3.40). Older patients admitted for ACS with or without revascularization were less likely to receive a statin. Patients who had received anti-platelets or angiotensin-modifying agents prior to their hospitalization were less likely to receive statins after discharge. Renal disease, prior stroke, diabetes, hypertension and hyperlipidemia did not influence statin utilization. Predictors of treatment did not change when the cohort was dichotomized according to length of stay. CONCLUSIONS: Patients are infrequently treated with statins when discharged to nursing homes following hospitalization for a symptomatic cardiovascular event. Barriers to statin treatment in this setting require closer examination.

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Setoguchi S, Choudhry NK, Levin R, Shrank WH, Winkelmayer WC. Temporal trends in adherence to cardiovascular medications in elderly patients after hospitalization for heart failure [Internet]. Clinical Pharmacology and Therapeutics 2010;88:548-54. Publisher's VersionAbstract

Although the complexity of treatment regimens for patients with heart failure (HF) has increased over time because of the increased availability of efficacious medications, little is known about temporal trends in adherence to treatment regimens in these patients. We assessed trends in adherence to angiotensin-system blockers (ABs), beta-blockers (BBs), and spironolactone (SL) for HF in Medicare beneficiaries enrolled in two statewide pharmacy benefit programs from 1995 to 2004. The proportion of days covered (PDC) (%) was assessed after the first dispensing among users of an AB, BB, or SL. Proportions of full adherence (PDC >80%) did not change over time for ABs (54% in both 1996 and 2003) but increased slightly for BBs (from 47% in 1996 to 57% in 2003) and SL (from 31% in 1996 to 42% in 2003). Black race and dialysis treatment predicted poor adherence to any medications. Adherence to BBs and SL increased modestly over time, but overall nonadherence remained high.

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2009
Choudhry NK, Schneeweiss S, Fischer MA, Liu J, Lii J, Solomon DH, Brookhart MA, Avorn J, Shrank WH. Reducing Co-Payments of Essential Cardiovascular Medications. Pharmacoepidemiology and Drug Safety 2009;18:S128. PDF
Dhalla IA, Smith MA, Choudhry NK, Denburg AE. Costs and benefits of free medications after myocardial infarction [Internet]. Healthcare Policy 2009;5:68-86. Publisher's VersionAbstract

BACKGROUND: Although combination pharmacotherapy after myocardial infarction dramatically reduces morbidity and mortality, the full benefits of secondary prevention medications remain unrealized owing to medication non-adherence. Because financial barriers are a major determinant of non-adherence, we examined the costs and benefits of providing free medications to myocardial infarction patients who do not have private insurance and are ineligible for substantial public coverage. METHODS: An economic evaluation combining decision analysis and Markov modelling was conducted to compare full public coverage of secondary prevention medications with the status quo. Costs and benefits were estimated using Canadian data wherever possible. The main outcome was the incremental cost-effectiveness ratio measured in cost per quality-adjusted life-year (QALY) gained. RESULTS: From the perspective of the publicly funded healthcare system, full coverage resulted in greater quality-adjusted survival than the status quo (7.02 vs. 6.13 QALYs) but at increased cost ($20,423 vs. $17,173). The incremental cost-effectiveness ratio (ICER) for full coverage compared to the status quo was $3,663/QALY. This result was robust to a wide range of sensitivity analyses. In a secondary analysis from the perspective of government, the ICER for full coverage compared to the status quo was $12,350/QALY. In this analysis, the ICER was sensitive to changes in price elasticity, but remained below $50,000/QALY as long as the elasticity remained below -0.035. INTERPRETATION: Public payers in Canada should consider providing secondary prevention medications to myocardial infarction patients without private insurance free of charge. Full public coverage is cost-effective compared to the status quo.

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Choudhry NK. Copayment levels and medication adherence: less is more [Internet]. Circulation 2009;119:365-7. Publisher's Version PDF
Rassen JA, Choudhry NK, Avorn J, Schneeweiss S. Cardiovascular outcomes and mortality in patients using clopidogrel with proton pump inhibitors after percutaneous coronary intervention or acute coronary syndrome [Internet]. Circulation 2009;120:2322-9. Publisher's VersionAbstract
BACKGROUND: Recent studies have raised concerns about the reduced efficacy of clopidogrel when used concurrently with proton pump inhibitors (PPIs), but those studies may have overestimated the risk. METHODS AND RESULTS: We studied the potential for increased risk of adverse cardiovascular events among users of clopidogrel with versus without concurrent use of PPIs in 3 large cohorts of patients > or =65 years of age, treated between 2001 and 2005. All patients had undergone percutaneous coronary intervention or had been hospitalized for acute coronary syndrome in Pennsylvania, New Jersey, or British Columbia, and subsequently had initiated treatment with clopidogrel. We recorded myocardial infarction hospitalization, death, and revascularization among PPI users and nonusers. We assessed our primary end point of myocardial infarction hospitalization or death using cohort-specific and pooled regression analyses. We entered 18 565 clopidogrel users into our analysis. On a pooled basis, 2.6% of those who also initiated a PPI versus 2.1% of PPI nonusers had a myocardial infarction hospitalization; 1.5% versus 0.9% died; and 3.4% versus 3.1% underwent revascularization. The propensity score-adjusted rate ratio for the primary end point of myocardial infarction or death was 1.22 (95% confidence interval, 0.99 to 1.51); for death, 1.20 (95% confidence interval, 0.84 to 1.70); and for revascularization, 0.97 (95% confidence interval, 0.79 to 1.21). Matched analyses generally yielded similar results. CONCLUSIONS: Although point estimates indicated a slightly increased risk of myocardial infarction hospitalization or death in older patients initiating both clopidogrel and a PPI, we did not observe conclusive evidence of a clopidogrel-PPI interaction of major clinical relevance. Our data suggest that if this effect exists, it is unlikely to exceed a 20% risk increase.
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Shrank WH, Porter ME, Jain SH, Choudhry NK. A blueprint for pharmacy benefit managers to increase value [Internet]. American Journal of Managed Care 2009;15:87-93. Publisher's VersionAbstract

Pharmacy benefit managers (PBMs) have a unique opportunity to promote health and generate value in the healthcare system. Today, PBMs are largely evaluated on their ability to control costs rather than improve health. Pharmacy benefit managers should be evaluated along 3 dimensions in which they can increase value: (1) use of cost-effective medications, (2) timely initiation of appropriate medication therapy, and (3) adherence to that therapy. Value creation requires the development of integrated data systems, stronger partnerships with patients and physicians, and improved measurement and reporting of results. Incentives for PBMs to promote value should drive innovation and improve health outcomes.

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Shrank WH, Gleason PP, Canning C, Walters C, Heaton AH, Jan S, Patrick A, Brookhart MA, Schneeweiss S, Solomon DH, Avorn J, Choudhry NK. Can improved prescription medication labeling influence adherence to chronic medications? An evaluation of the target pharmacy label [Internet]. Journal of General Internal Medicine 2009;24:570-8. Publisher's VersionAbstract

BACKGROUND: Prescription medication labels contain valuable health information, and better labels may enhance patient adherence to chronic medications. A new prescription medication labeling system was implemented by Target pharmacies in May 2005 and aimed to improve readability and understanding. OBJECTIVE: We evaluated whether the new Target label influenced patient medication adherence. DESIGN AND PATIENTS: Using claims from two large health plans, we identified patients with one of nine chronic diseases who filled prescriptions at Target pharmacies and a matched sample who filled prescriptions at other community pharmacies. MEASUREMENTS: We stratified our cohort into new and prevalent medication users and evaluated the impact of the Target label on medication adherence. We used linear regression and segmented linear regression to evaluate the new-user and prevalent-user analyses, respectively. RESULTS: Our sample included 23,745 Target users and 162,368 matched non-Target pharmacy users. We found no significant change in adherence between new users of medications at Target or other community pharmacies (p = 0.644) after implementing the new label. In prevalent users, we found a 0.0069 percent reduction in level of adherence (95% CI -0.0138-0.0; p < 0.001) and a 0.0007 percent increase in the slope in Target users (the monthly rate of change of adherence) after implementation of the new label (95% CI 0.0001-0.0013; p = 0.001). CONCLUSIONS: We found no changes in adherence of chronic medication in new users, and small and likely clinically unimportant changes in prevalent users after implementation of the new label. While adherence may not be improved with better labeling, evaluation of the effect of labeling on safety and adverse effects is needed.

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Solomon DH, Cadarette SM, Choudhry NK, Canning C, Levin R, Sturmer T. A cohort study of thiazolidinediones and fractures in older adults with diabetes [Internet]. Journal of Clinical Endocrinology and Metabolism 2009;94:2792-8. Publisher's VersionAbstract

CONTEXT: Thiazolidenediones (TZDs) are selective ligands of peroxisome-proliferator-activated receptor-gamma and have been shown to reduce bone mineral density. Recent results from several randomized controlled trials find an increased risk of fracture with TZDs compared with other oral antidiabetic agents. OBJECTIVE: The aim of the study was to determine the association between TZD use and fracture risk among older adults with diabetes. DESIGN: We conducted a cohort study. PARTICIPANTS: Medicare beneficiaries with at least one diagnosis of diabetes initiating monotherapy for an oral hypoglycemic agent participated in the study. MAIN OUTCOME: We measured the incidence of fracture within the cohort. RESULTS: Among the 20,964 patients with diabetes eligible for this study, 686 (3.3%) experienced a fracture during the median follow-up of approximately 10 months. Although not statistically significant, patients using only a TZD were more likely to experience a fracture than those using metformin (adjusted relative risk, 1.31; 95% confidence interval, 0.98-1.77; P = 0.071) or a sulfonylurea (adjusted relative risk, 1.21; 95% confidence interval, 0.94-1.55; P = 0.12). Each individual TZD was associated with an increased risk, with confidence intervals overlapping unity, compared with both metformin and sulfonylureas. The adjusted risk of any fracture associated with TZD use compared with metformin was elevated for non-insulin-using patients, women and men. If TZD use is associated with fractures, the number needed for one excess fracture when comparing TZD users to sulfonylurea users was 200, and the number was 111 when comparing TZDs with metformin. CONCLUSIONS: As has been found with other analyses, our data suggest that TZDs may be associated with an increased risk of fractures compared with oral sulfonylureas and metformin.

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Patrick AR, Avorn J, Choudhry NK. Cost-effectiveness of genotype-guided warfarin dosing for patients with atrial fibrillation [Internet]. Circulation. Cardiovascular Quality and Outcomes 2009;2:429-36. Publisher's VersionAbstract

BACKGROUND: CYP2C9 and VKORC1 genotyping has been advocated as a means of improving the accuracy of warfarin dosing. However, the effectiveness of genotyping in improving anticoagulation control and reducing major bleeding has not yet been compellingly demonstrated. Genotyping currently costs $400 to $550. METHODS AND RESULTS: We constructed a Markov model to evaluate whether and under what circumstances genetically-guided warfarin dosing could be cost-effective for newly diagnosed atrial fibrillation patients. Estimates of clinical event rates, treatment and adverse event costs, and utilities for health states were derived from the published literature. The cost-effectiveness of genetically-guided dosing was highly dependent on the assumed effectiveness of genotyping in increasing the amount of time patients spend appropriately anticoagulated. If genotyping increases the time spent in the target international normalized ratio range by <5 percentage points, its incremental cost-effectiveness ratio would be greater than $100,000 per quality-adjusted life year. The incremental cost-effectiveness ratio falls below $50,000 per quality-adjusted life year if genotyping increases the time spent in range by 9 percentage points. The results were also sensitive to assumptions about the rate of major bleeding events during treatment initiation and the cost of the test. CONCLUSIONS: Our results suggest that genotyping before warfarin initiation will be cost-effective for patients with atrial fibrillation only if it reduces out-of-range international normalized ratio values by more than 5 to 9 percentage points compared with usual care. Given the current uncertainty surrounding genotyping efficacy, caution should be taken in advocating the widespread adoption of this strategy.

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Thavendiranathan P, Bagai A, Khoo C, Dorian P, Choudhry NK. Does this patient with palpitations have a cardiac arrhythmia? [Internet]. Journal of the American Medical Association 2009;302:2135-43. Publisher's VersionAbstract

CONTEXT: Many patients have palpitations and seek advice from general practitioners. Differentiating benign causes from those resulting from clinically significant cardiac arrhythmia can be challenging and the clinical examination may aid in this process. OBJECTIVE: To systematically review the accuracy of historical features, physical examination, and cardiac testing for the diagnosis of cardiac arrhythmia in patients with palpitations. Data Source, Study Selection, and DATA EXTRACTION: MEDLINE (1950 to August 25, 2009) and EMBASE (1947 to August 2009) searches of English-language articles that compared clinical features and diagnostic tests in patients with palpitations with a reference standard for cardiac arrhythmia. Of the 277 studies identified by the search strategy, 7 studies were used for accuracy analysis and 16 studies for diagnostic yield analysis. Two authors independently reviewed articles for study data and quality and a third author resolved disagreements. DATA SYNTHESIS: Most data were obtained from single studies with small sample sizes. A known history of cardiac disease (likelihood ratio [LR], 2.03; 95% confidence interval [CI], 1.33-3.11), having palpitations affected by sleeping (LR, 2.29; 95% CI, 1.33-3.94), or while the patient is at work (LR, 2.17; 95% CI, 1.19-3.96) slightly increase the likelihood of a cardiac arrhythmia. A known history of panic disorder (LR, 0.26; 95% CI, 0.07-1.01) or having palpitations lasting less than 5 minutes (LR, 0.38; 95% CI, 0.22-0.63) makes the diagnosis of cardiac arrhythmia slightly less likely. The presence of a regular rapid-pounding sensation in the neck (LR, 177; 95% CI, 25-1251) or visible neck pulsations (LR, 2.68; 95% CI, 1.25-5.78) in association with palpitations increases the likelihood of a specific type of arrhythmia (atrioventricular nodal reentry tachycardia). The absence of a regular rapid-pounding sensation in the neck makes detecting the same arrhythmia less likely (LR, 0.07; 95% CI, 0.03-0.19). No other features significantly alter the probability of clinically significant arrhythmia. Diagnostic tests for prolonged periods of electrocardiographic monitoring vary in their yield depending on the modality used, duration of monitoring, and occurrence of typical symptoms during monitoring. Loop monitors have the highest diagnostic yield (34%-84%) for identifying an arrhythmia. CONCLUSIONS: While the presence of a regular rapid-pounding sensation in the neck or visible neck pulsations associated with palpitations makes the diagnosis of atrioventricular nodal reentry tachycardia likely, the reviewed studies suggest that the clinical examination is not sufficiently accurate to exclude clinically significant arrhythmias in most patients. Thus, prolonged electrocardiographic monitoring with demonstration of symptom-rhythm correlation is required to make the diagnosis of a cardiac arrhythmia for most patients with recurrent palpitations.

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Choudhry NK, Lee JL, Agnew-Blais J, Corcoran C, Shrank WH. Drug company-sponsored patient assistance programs: a viable safety net? [Internet]. Health Affairs (Millwood) 2009;28:827-34. Publisher's VersionAbstract

Drug company-sponsored patient assistance programs (PAPs) provide access to brand-name medications at little or no cost and have been advocated as a safety net for inadequately insured patients. Yet little is known about these programs. We surveyed drug company-sponsored PAPs and found much variability in their structures and application processes. Most cover one or two drugs. Only 4 percent disclosed how many patients they had directly helped, and half would not disclose their income eligibility criteria. A better understanding of PAPs might clarify their role in improving access to medications, the adequacy of existing public programs, and their impact on cost-effective medication use.

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Charytan DM, Wallentin L, Lagerqvist B, Spacek R, De Winter RJ, Stern NM, Braunwald E, Cannon CP, Choudhry NK. Early angiography in patients with chronic kidney disease: a collaborative systematic review [Internet]. Clinical Journal of the American Society of Nephrology 2009;4:1032-43. Publisher's VersionAbstract

BACKGROUND AND OBJECTIVES: In the general population, an early invasive strategy of routine coronary angiography is superior to a conservative strategy of selective angiography in patients who are admitted with unstable angina or non-ST segment elevation myocardial infarction (MI), but the effectiveness of this strategy in individuals with chronic kidney disease (CKD) is uncertain. DESIGN, SETTING, PARTICIPANTS, & MEASUREMENTS: We conducted a collaborative meta-analysis with data provided by the main authors of identified trials to estimate the effectiveness of early angiography in patients with CKD. The Cochrane, Medline, and EMBASE databases were searched to identify randomized trials that compared invasive and conservative strategies in patients with unstable angina or non-ST MI. Pooled risks ratios were estimated using data from enrolled patients with estimated GFR <60 ml/min per 1.73 m(2). RESULTS: Five randomized trials that enrolled 1453 patients with CKD were included. An early invasive strategy was associated with nonsignificant reductions in all-cause mortality, nonfatal MI, and a composite of death or nonfatal MI. The invasive strategy significantly reduced rehospitalization. CONCLUSIONS: This collaborative study suggests that the benefits of an early invasive strategy are preserved in patients with CKD and that an early invasive approach reduces the risk for rehospitalization and is associated with trends of reduction in the risk for death and nonfatal re-infarction in patients with CKD. Coronary angiography should be considered for patients who have CKD and are admitted with non-ST elevation acute coronary syndromes.

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Shrank WH, Patrick A, Gleason PP, Canning C, Walters C, Heaton AH, Jan S, Brookhart MA, Schneeweiss S, Solomon DH, Wolf MS, Avorn J, Choudhry NK. An evaluation of the relationship between the implementation of a newly designed prescription drug label at Target pharmacies and health outcomes [Internet]. Medical Care 2009;47:1031-5. Publisher's VersionAbstract

BACKGROUND: Medication errors represent a major public health concern, and inadequate prescription drug labels have been identified as a root cause of errors. A new prescription medication labeling system was implemented by Target pharmacies in May 2005 and aimed to improve health outcomes. OBJECTIVES: To evaluate whether the new Target label influenced patient health services utilization. SUBJECTS: Derived from 2 large health plans. RESEARCH DESIGN AND MEASURES: Using administrative claims, we identified patients with 1 of 9 chronic diseases who filled prescriptions at Target pharmacies and a matched sample who filled prescriptions at other community pharmacies. We stratified our cohort into new and prevalent medication users and evaluated the impact of the Target label on outpatient, emergency department and inpatient health services use. We used linear regression and segmented linear regression to evaluate the new-user and prevalent-user analyses, respectively. RESULTS: Our sample included 23,745 Target pharmacy users and 162,369 matched non-Target pharmacy users. In the new-user analysis, we found no significant change in rates of both outpatient (event rate ratio: 0.53; 95% CI: 0.15-1.86) and inpatient and emergency department (Event rate ratio: 0.88; 95% CI: 0.62-1.24) health services utilization in Target users after implementation when compared with non-Target users. Similarly, in the prevalent user analysis, we found no change in the level or slope of outpatient or emergency/inpatient services in Target users after implementation of the new label when compared with non-Target users. CONCLUSIONS: We found no statistically significant change in health services use attributable to the implementation of the new prescription drug label at Target pharmacies. These findings highlight the challenge of influencing health outcomes with interventions to improve health literacy.

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Gellad WF, Detsky AS, Choudhry NK. Implications of recent clinical trials on pay-for-performance [Internet]. American Journal of Health-System Pharmacy 2009;66:864-7. Publisher's Version PDF
Choudhry NK, Shrank WH, Levin RL, Lee JL, Jan SA, Brookhart MA, Solomon DH. Measuring concurrent adherence to multiple related medications [Internet]. American Journal of Managed Care 2009;15:457-64. Publisher's VersionAbstract

OBJECTIVES: To propose standardized methods for measuring concurrent adherence to multiple related medications and to apply these definitions to a cohort of patients with diabetes mellitus. STUDY DESIGN: Retrospective cohort study of 7567 subjects with diabetes prescribed 2 or more classes of oral hypoglycemic agents in 2005. METHODS: For each medication class, adherence for each patient was estimated using prescription-based and interval-based measures of proportion of days covered (PDC) from cohort entry until December 31, 2006. Concurrent adherence was calculated by applying these 2 measures in the following 3 ways: (1) the mean of each patient's average PDC, (2) the proportion of days during which patients had at least 1 of their medications available to them, and (3) the proportion of patients with a PDC of at least 80% for all medication classes. Because patients taking multiple related medications have distinct patterns of use, the analysis was repeated after classifying patients into mutually exclusive groups. RESULTS: Concurrent medication adherence ranged from 35% to 95% depending on the definition applied. Interval-based measures provide lower estimates than prescription-based techniques. Definitions that require the use of at least 1 drug class categorize virtually all patients as adherent. Requiring patients to have a PDC of at least 80% for each of their drugs results in only 30% to 40% of patients being defined as adherent. The variability in adherence is greatest for patients whose treatment regimen changed the most during follow-up. CONCLUSIONS: The variability in adherence estimates derived from different definitions may substantially impact qualitative conclusions about concurrent adherence to related medications. Because the measures we propose have different underlying assumptions, the choice of technique should depend on why adherence is being evaluated.

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