BACKGROUND

Information comparing characteristics of patients who do and do not pick up their prescriptions is sparse, in part because adherence measured using pharmacy claims databases does not include information on patients who never pick up their first prescription, that is, patients with primary non-adherence. Electronic health record medication order entry enhances the potential to identify patients with primary non-adherence, and in organizations with medication order entry and pharmacy information systems, orders can be linked to dispensings to identify primarily non-adherent patients.

OBJECTIVE

This study aims to use database information from an integrated system to compare patient, prescriber, and payment characteristics of patients with primary non-adherence and patients with ongoing dispensings of newly initiated medications for hypertension, diabetes, and/or hyperlipidemia.

DESIGN

This is a retrospective observational cohort study.

PARTICIPANTS (OR PATIENTS OR SUBJECTS)

Participants of this study include patients with a newly initiated order for an antihypertensive, antidiabetic, and/or antihyperlipidemic within an 18-month period.

MAIN MEASURES

Proportion of patients with primary non-adherence overall and by therapeutic class subgroup. Multivariable logistic regression modeling was used to investigate characteristics associated with primary non-adherence relative to ongoing dispensings.

KEY RESULTS

The proportion of primarily non-adherent patients varied by therapeutic class, including 7% of patients ordered an antihypertensive, 11% ordered an antidiabetic, 13% ordered an antihyperlipidemic, and 5% ordered medications from more than one of these therapeutic classes within the study period. Characteristics of patients with primary non-adherence varied across therapeutic classes, but these characteristics had poor ability to explain or predict primary non-adherence (models c-statistics = 0.61–0.63).

CONCLUSIONS

Primary non-adherence varies by therapeutic class. Healthcare delivery systems should pursue linking medication orders with dispensings to identify primarily non-adherent patients. We encourage conduct of research to determine interventions successful at decreasing primary non-adherence, as characteristics available from databases provide little assistance in predicting primary non-adherence.

Objectives

Inverse probability of treatment weighted (IPTW) Kaplan-Meier estimates have been developed to compare two treatments in the presence of confounders in observational studies. Recently, stabilized weights were developed to reduce the influence of extreme IPTW weights in estimating treatment effects. The objective of this paper was to use adjusted Kaplan-Meier estimates and modified log-rank and Wilcoxon tests to examine the effect of a treatment which varies over time in an observational study.

Methods

In this paper, we propose stabilized weight (SW) adjusted Kaplan-Meier estimates and modified log-rank and Wilcoxon tests when the treatment is time-varying over the follow-up period. We applied these new methods in examining the effect of an anti-platelet agent, clopidogrel, on subsequent events, including bleeding, myocardial infarction, and death after a Drug-Eluting Stent was implanted into a coronary artery. In this population, clopidogrel use may change over time based on patients' behavior (e.g., non-adherence) and physicians' recommendations (e.g., end of duration of therapy). Consequently, clopidogrel use was treated as a time-varying variable.

Results

We demonstrate that 1) the sample sizes at three chosen time points are almost identical in the original and weighted datasets, and 2) the covariates between patients on and off clopidogrel were well balanced after SWs were applied to the original samples.

Conclusions

The SW-adjusted Kaplan-Meier estimates and modified log-rank and Wilcoxon tests are useful in presenting and comparing survival functions for time-varying treatments in observational studies while adjusting for known confounders.

We developed an accurate and valid medication order algorithm to identify from electronic health records the definitive medication order intended for dispensing and applied this process to identify a cohort of patients and to stratify them into one of three medication adherence groups: early non-persistence, primary non-adherence, or ongoing adherence. We identified medication order data from electronic health record tables, obtained the orders, and linked the orders to dispensings. These steps were then used to identify patients newly prescribed antihypertensive, antidiabetic, or antihyperlipidemic medications and to determine the adherence group of each patient. Record review validated each process step, thus increasing the accuracy of group assignment as well as the criteria used to select patients. This work is an important first step to accurately identify study-specific patient adherence cohorts and allow more comprehensive estimates of population medication adherence.

Context

More than 1.5 million US adults use stimulants and other medications labeled for treatment of attention deficit hyperactivity disorder (ADHD). These agents can increase heart rate and blood pressure, raising concerns about their cardiovascular safety.

Objective

Examine whether current use of medications used primarily to treat ADHD is associated with increased risk of serious cardiovascular events in young and middle-aged adults.

Design

Retrospective, population-based cohort study

Setting

Computerized health records from 4 study sites (OptumInsight Epidemiology, Tennessee Medicaid, Kaiser Permanente California, and the HMO Research Network), starting in 1986 at one site and ending in 2005 at all sites, with additional covariate assessment using 2007 survey data.

Participants

Adults aged 25–64 years with dispensed prescriptions for methylphenidate, amphetamine, or atomoxetine at baseline. Each medication user (n=150,359) was matched to two non-users on study site, birth year, sex, and calendar year (total users and non-users=443,198).

Main Outcome

Serious cardiovascular events, including myocardial infarction (MI), sudden cardiac death (SCD), or stroke. Comparison between current or new users and remote users to account for potential healthy user bias.

Results

During 806,182 person-years of follow-up (median 1.3 years per person), 1357 cases of MI, 296 cases of SCD, and 575 cases of stroke occurred. There were 107,322 person-years of current use (median 0.33 years), with a crude incidence per 1000 person-years of 1.34 (95% CI, 1.14–1.57) for MI, 0.30 (95% CI, 0.20–0.42) for SCD, and 0.56 (95% CI, 0.43–0.72) for stroke. The multivariable adjusted rate ratio (RR) of serious cardiovascular events for current use vs non-use of ADHD medications was 0.83 (95% CI 0.72–0.96). Among new users of ADHD medications, the adjusted RR was 0.77 (95% CI 0.63–0.94). The adjusted RR was 1.03 (95% CI, 0.86–1.24) for current use vs remote use, and was 1.02 (95% CI, 0.82–1.28) for new use vs remote use.

Conclusion

Among young and middle-aged adults, current or new use of ADHD medications, compared with non-use or remote use, was not associated with an increased risk of serious cardiovascular events. Apparent protective associations likely represent healthy user bias.

To determine the incidence of Clostridium difficile infection during 2007, we examined infection in adult inpatient and outpatient members of a managed-care organization. Incidence was 14.9 C. difficile infections per 10,000 patient-years. Extrapolating this rate to US adults, we estimate that 284,875 C. difficile infections occurred during 2007.

Purpose

Calcium channel blockers and beta-blockers are widely used during pregnancy, but data on their safety for the developing infant is scarce. We used population-based data from 5 HMOs to study risks for perinatal complications and congenital defects among infants exposed in-utero.

Methods

We studied women older than 15 years delivering an infant between 1/1/96 to 12/31/00, who had been continuously enrolled with prescription drug coverage for >= one year prior to delivery. Information on prescription drug dispensings, inpatient and outpatient diagnoses and procedures was obtained from automated databases at each HMO.

Results

There were 584 full-term infants exposed during pregnancy to beta-blockers and 804 full-term infants exposed to calcium-channel blockers, and over 75,000 unexposed mother-infant pairs with >= 30 days follow-up. Infants exposed to beta-blockers in the third trimester of pregnancy had over three-fold increased risk for hypoglycemia (RR 3.1; 95% CI 2.2, 4.2) and an approximately two-fold increased risk for feeding problems (RR 1.8; 95% CI 1.3, 2.5). Infants exposed to calcium-channel blockers in the third trimester had an increased risk for seizures (RR 3.6 95% CI 1.3, 10.4). Chart review confirmed the majority of the exposed seizure and hypoglycemia cases. There were no increased risks for congenital anomalies among either group of infants, except for the category of upper alimentary tract anomalies; this increased risk was based on only two exposed cases.

Conclusions

Infants whose mothers receive beta-blockers are at increased risk for neonatal hypoglycemia, while those whose mothers take calcium-channel blockers are at increased risk for neonatal seizures.

Introduction

Electronic health record (EHR) data enhance opportunities for conducting surveillance of diabetes. The objective of this study was to identify the number of people with diabetes from a diabetes DataLink developed as part of the SUPREME-DM (SUrveillance, PREvention, and ManagEment of Diabetes Mellitus) project, a consortium of 11 integrated health systems that use comprehensive EHR data for research.

Methods

We identified all members of 11 health care systems who had any enrollment from January 2005 through December 2009. For these members, we searched inpatient and outpatient diagnosis codes, laboratory test results, and pharmaceutical dispensings from January 2000 through December 2009 to create indicator variables that could potentially identify a person with diabetes. Using this information, we estimated the number of people with diabetes and among them, the number of incident cases, defined as indication of diabetes after at least 2 years of continuous health system enrollment.

Results

The 11 health systems contributed 15,765,529 unique members, of whom 1,085,947 (6.9%) met 1 or more study criteria for diabetes. The nonstandardized proportion meeting study criteria for diabetes ranged from 4.2% to 12.4% across sites. Most members with diabetes (88%) met multiple criteria. Of the members with diabetes, 428,349 (39.4%) were incident cases.

Conclusion

The SUPREME-DM DataLink is a unique resource that provides an opportunity to conduct comparative effectiveness research, epidemiologic surveillance including longitudinal analyses, and population-based care management studies of people with diabetes. It also provides a useful data source for pragmatic clinical trials of prevention or treatment interventions.

ICD-9 codes are conventionally used to identify pelvic inflammatory disease (PID) from administrative data for surveillance purposes. This approach may include non-PID cases. To refine PID case identification among women with ICD-9 codes suggestive of PID, a case-finding algorithm was developed using additional variables. Potential PID cases were identified among women aged 15–44 years at Group Health (GH) and Kaiser Permanente Colorado (KPCO) and verified by medical record review. A classification and regression tree analysis was used to develop the algorithm at GH; validation occurred at KPCO. The positive predictive value (PPV) for using ICD-9 codes alone to identify clinical PID cases was 79%. The algorithm identified PID appropriate treatment and age 15–25 years as predictors. Algorithm sensitivity (GH = 96.4%; KPCO = 90.3%) and PPV (GH = 86.9%; KPCO = 84.5%) were high, but specificity was poor (GH = 45.9%; KPCO = 37.0%). In GH, the algorithm offered a practical alternative to medical record review to further improve PID case identification.

Purpose

Our objectives were to determine performance of coded hyperkalemia diagnosis at identifying 1) clinically-evident hyperkalemia and 2) serum potassium ≥ 6 mmol/liter.

Methods

This retrospective observational study included 8,722 patients with diabetes within an integrated healthcare system who newly-initiated an angiotensin converting enzyme inhibitor, angiotensin receptor blocker, or spironolactone. The primary outcome was first hyperkalemia-associated event (hospitalization, emergency department visit or death within 24 hours of coded diagnosis and/or potassium ≥ 6 mmol/liter) during the first year of therapy. Medical records were reviewed.

Results

Among a random sample of 99 patients not coded as having hyperkalemia, none had hyperkalemia upon record review. Among all 64 patients identified as having hyperkalemia, all had hospitalization or emergency department visit associated with coded diagnosis or elevated potassium. Of 55 with coded diagnosis, 42 (PPV 76%) had clinically-evident hyperkalemia; 32 (PPV 58%) had potassium ≥ 6. Of 9 identified using only potassium ≥ 6, 7 (PPV 78%) had clinically-evident hyperkalemia.

Conclusions

Nearly one-fourth of patients with coded diagnosis do not have clinically-evident hyperkalemia and nearly one-half do not have potassium ≥ 6. Because both false positives and negatives occur with coded diagnoses, medical record validation of hyperkalemia-associated outcomes is necessary.

Rationale: Single-site clinic-based studies suggest an increasing prevalence of pulmonary nontuberculous mycobacteria (NTM) disease, but systematic data are lacking.

Objectives: To describe prevalence and trends for NTM lung disease at four geographically diverse integrated heath care delivery systems in the United States.

Methods: We abstracted mycobacterial culture results from electronic laboratory databases and linked to other datasets containing clinical and demographic information. Possible cases were defined as a single positive NTM pulmonary isolate, and definite cases were defined as two positive sputum cultures, or one positive culture from a bronchoalveolar lavage or lung biopsy. Annual prevalence was calculated using United States census data; average annual prevalence is presented for 2004–2006. Poisson regression models were used to estimate the annual percent change in prevalence.

Measurements and Main Results: A total of 28,697 samples from 7,940 patients were included in the analysis. Of these, 3,988 (50%) were defined as possible cases, and 1,865 (47%) of these were defined as definite cases. Average annual (2004–2006) site-specific prevalence ranged from 1.4 to 6.6 per 100,000. Prevalence was 1.l- to 1.6-fold higher among women relative to men across sites. The prevalence of NTM lung disease was increasing significantly at the two sites where trends were studied, by 2.6% per year among women and 2.9% per year among men. Among persons aged greater than or equal to 60 years, annual prevalence increased from 19.6 per 100,000 during 1994–1996 to 26.7 per 100,000 during 2004–2006.

Conclusions: The epidemiology of nontuberculous mycobacterial lung disease is changing, with a predominance of women and increasing prevalence at the sites studied.

BACKGROUND

Renin-angiotensin-aldosterone system (RAAS) inhibitors are associated with hyperkalemia, but there is little evidence demonstrating patients who receive potassium monitoring have a lower rate of hyperkalemia.

OBJECTIVE

To evaluate the association between potassium monitoring and serious hyperkalemia-associated adverse outcomes among patients with diabetes newly initiating RAAS inhibitor therapy.

DESIGN

Retrospective observational study.

PARTICIPANTS

Patients with diabetes without end-stage renal disease initiating RAAS inhibitor therapy between 2001 and 2006 at three integrated health care systems.

MEASUREMENTS

Potassium monitoring and first hyperkalemia-associated adverse event during the initial year of therapy. Hyperkalemia-associated adverse events included hospitalizations, emergency department visits or deaths within 24 h of hyperkalemia diagnosis and/or diagnostic potassium ≥6 mmol/l. Incidence rates were calculated in person-years (p-y). We used inverse probability propensity score weighting to adjust for differences between patients with and without monitoring; Poisson regression was used to obtain adjusted relative risks.

RESULTS

A total of 19,391 of 27,355 patients (71%) received potassium monitoring. Serious hyperkalemia-associated events occurred at an incidence rate of 10.2 per 1,000 p-y. Compared to patients without monitoring, adjusted relative risk of hyperkalemia-associated adverse events among all patients with monitoring was 0.50 (0.37, 0.66); in the subset of patients who also had chronic kidney disease (n = 2,176), adjusted relative risk was 0.29 (0.18, 0.46).

CONCLUSIONS

Patients prescribed RAAS inhibitors who have both diabetes and chronic kidney disease and receive potassium monitoring are less likely to experience a serious hyperkalemia-associated adverse event compared to similar patients who did not receive potassium monitoring. This evidence supports existing consensus-based guidelines.

Objective

To identify gaps in therapy with urate-lowering drugs for the treatment of gout as well as factors associated with resuming therapy.

Methods

We identified persons from two integrated delivery systems 18 years or older with a diagnosis of gout who initiated use of a urate-lowering drug from January 1, 2000 through June 30, 2006 and who had a gap in therapy. A gap was defined as a period of over 60 days after the completion of one prescription in which no refill for a urate-lowering drug was obtained. Survival curves were used to assess return to therapy of urate-lowering drugs. Cox proportional hazards analysis estimated the association between covariates and return to therapy.

Results

There were 4,166 new users of urate-lowering drugs (97% received allopurinol) of whom 2,929 (70%) had a gap in therapy. Among those with a gap, in 75% it occurred in the first year of therapy. Fifty percent of patients with a gap returned to therapy within 8 months, and by 4 years it was 75%. Age 45 to 74 (<45 referent) and greater duration of urate-lowering drug use prior to the gap was associated with resuming treatment within one year. In contrast, receipt of NSAIDs or glucocorticoids in the year prior to the gap was associated with a reduced likelihood of resuming therapy.

Conclusions

The majority of gout patients with gaps in urate-lowering drug use returned to treatment. More investigation is needed to better understand why patients may go for months without refilling prescriptions given the clinical consequences of nonadherence.

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.

Objective: We conducted a study to assess the educational needs and interests of medication prescribers and organizational needs regarding heavily marketed drugs.

Study design: We used an Internet and paper-based educational needs assessment survey to gather data.

Methods: Approximately 1000 Denver-area Kaiser Permanente Colorado (KPCO) physicians, nurse practitioners, and physician assistants (“health maintenance organization [HMO] prescribers”); 780 Colorado Springs KPCO network (preferred provider organization [PPO] prescribers); and 36 Denver-area KPCO pharmacy leaders were surveyed. Prescribers were asked about interest in pharmaceutical development, approval, and marketing processes and interest in learning about accessing and using drug information in practice. They were also asked to identify areas in which they would like to improve prescribing practices. Organizational leaders were asked about areas in which curricula could assist current cost-effective prescribing efforts. HMO prescriber and leader surveys were conducted via the Internet. PPO learner surveys were conducted by mail.

Results: Responses were collected from 127 (13%) HMO and 70 (9%) PPO prescribers. Top interest areas in both groups were accessing unbiased drug information, comparing evidence about drugs within class, critical appraisal of drug information, off-label drug use, and addressing patient medication inquiries. Pharmaceutical industry marketing practices, roles and responsibilities of the US Food and Drug Administration, and the US drug development and approval process were rated lowest. HMO prescribers most wanted to improve prescribing for bacterial infections, depression, and diabetes; PPO prescribers also wanted to improve prescribing for migraine headaches. Highest organizational priority drug classes were those for depression and asthma.

Conclusions: Prescribers are interested in areas of pharmaceutical development and marketing that relate closely to providing patient care, especially in commonly seen clinical conditions. They are less interested in regulatory or policy aspects of the process.

Objective

This study sought to determine whether a computerized tool that alerted pharmacists when pregnant patients were prescribed U.S. Food and Drug Administration pregnancy risk category D or X medications was effective in decreasing dispensings of these medications.

Design

Randomized trial. Pharmacy, diagnostic, and laboratory data were linked to identify pregnant patients prescribed targeted medications. Women (n = 11,100) were randomized to intervention or usual care. Physicians and pharmacists collaborated on the intervention.

Measurements

The primary outcome was the proportion of pregnant women dispensed a category D or X medication. The secondary outcome was the total number of first dispensings of targeted medications.

Results

A total of 2.9% of intervention (n = 177) and 5.5% of usual care (n = 276) patients were dispensed targeted medications (p < 0.001): 1.8% of intervention (n = 108) and 3.9% of usual care (n = 198) patients were dispensed only category D medication(s); 0.9% of intervention (n = 54) and 1.2% of usual care (n = 58) patients were dispensed only category X medication(s); 0.2% of intervention (n = 15) and 0.4% of usual care (n = 20) patients were dispensed both category D and X medications (p = 0.05). This resulted in intervention patients receiving 238 dispensings of unique targeted medications and usual care patients receiving 361 dispensings of unique targeted medications (p = 0.03). The study was stopped primarily due to 2 false-positive alert types: Misidentification of medications as contraindicated in pregnancy by the pharmacy information system and misidentification of pregnancy related to delayed transfer of diagnosis information.

Conclusion

Coupling data from information systems with knowledge and skills of physicians and pharmacists resulted in improved prescribing safety. Systems limitations contributed to project discontinuation. Linking ambulatory clinical, laboratory, and pharmacy information to provide safety alerts is not sufficient to ensure project success and sustainability.

Background and Objectives

Product labeling and published guidelines reflect the importance of monitoring laboratory parameters for drugs with a risk of organ system toxicity or electrolyte imbalance. Limited information exists about adherence to laboratory monitoring recommendations. The objective of this study was to describe laboratory monitoring among ambulatory patients dispensed medications for which laboratory testing is recommended at therapy initiation.

Design and Subjects

We conducted a retrospective cross-sectional analysis of patients in 10 geographically distributed health maintenance organizations who were newly prescribed medications with recommended laboratory test monitoring. The main outcome measure was the proportion of initial drug dispensing without recommended baseline laboratory monitoring for 35 newly initiated drugs or drug classes.

Results

One hundred seven thousand, seven hundred sixty-three of 279,354 (39%) initial drug dispensings occurred without recommended laboratory monitoring. Patients without monitoring were younger than patients who had monitoring (median 57 vs 61 years, P<.001). Thirty-two percent of dispensings where a serum creatinine was indicated did not have it evaluated (range across drugs, 12% to 61%); 39% did not have liver function testing (range 10% to 75%); 32% did not have hematologic monitoring (range 9% to 51%); and 34% did not have electrolyte monitoring (range 20% to 62%) (P<.001).

Conclusions

Substantial opportunity exists to improve laboratory monitoring of drugs for which such monitoring is recommended. This study emphasizes the need for research to identify the clinical implications of not conducting recommended laboratory monitoring, existing barriers to monitoring, and methods to improve practice.