Positive predictive value of the diagnosis of acute myocardial infarction in an administrative database

Concordance Between Clinical Diagnosis and Medicare Claims of Depression Among Older Primary Care Patients

OBJECTIVE

To identify patient characteristics associated with concordance of Medicare claims with clinically identified depression.

METHODS

The authors studied a cohort of 742 older primary care patients linked to Medicare claims data using the Structured Clinical Interview for Diagnostic and Statistical Manual of Mental Disorders, Fourth Edition major depressive disorder and clinically significant minor depression.

RESULTS

Among 474 patients with depression, 198 patients had a Medicare claim for depression (sensitivity: 42%; 95% confidence interval [CI]: 37%-46%). Among 268 patients who did not meet criteria for depression, 235 patients did not have a Medicare claim for depression (specificity: 88%; 95% CI: 83%-91%). After adjustment for demographic and clinical characteristics, non-white participants were nearly twice as likely not to have Medicare claims for depression among patients who met criteria for depression ("false negatives"). Smoking status, depression severity (Hamilton Depression Rating Scale), cardiovascular disease, and more primary care physician office visits were also significantly associated with decreased odds to be false negatives. In contrast, after covariate adjustment, white race and chronic pulmonary disease were associated with increased odds of a Medicare claim for depression among patients who did not meet criteria for depression ("false positives"). Using weights based on the screened sample, the positive predictive value of a Medicare claim for depression was 66% (95% CI [63%, 69%]), whereas the negative predictive value was 77% (95% CI [76%, 78%]).

CONCLUSION

Investigators using Medicare data to study depression must recognize that diagnoses of depression from Medicare data may be biased by patient ethnicity and the presence of medical comorbidity.

Follow-up of glycemic control and cardiovascular outcomes in type 2 diabetes

BACKGROUND

The Veterans Affairs Diabetes Trial previously showed that intensive glucose lowering, as compared with standard therapy, did not significantly reduce the rate of major cardiovascular events among 1791 military veterans (median follow-up, 5.6 years). We report the extended follow-up of the study participants.

METHODS

After the conclusion of the clinical trial, we followed participants, using central databases to identify procedures, hospitalizations, and deaths (complete cohort, with follow-up data for 92.4% of participants). Most participants agreed to additional data collection by means of annual surveys and periodic chart reviews (survey cohort, with 77.7% follow-up). The primary outcome was the time to the first major cardiovascular event (heart attack, stroke, new or worsening congestive heart failure, amputation for ischemic gangrene, or cardiovascular-related death). Secondary outcomes were cardiovascular mortality and all-cause mortality.

RESULTS

The difference in glycated hemoglobin levels between the intensive-therapy group and the standard-therapy group averaged 1.5 percentage points during the trial (median level, 6.9% vs. 8.4%) and declined to 0.2 to 0.3 percentage points by 3 years after the trial ended. Over a median follow-up of 9.8 years, the intensive-therapy group had a significantly lower risk of the primary outcome than did the standard-therapy group (hazard ratio, 0.83; 95% confidence interval [CI], 0.70 to 0.99; P=0.04), with an absolute reduction in risk of 8.6 major cardiovascular events per 1000 person-years, but did not have reduced cardiovascular mortality (hazard ratio, 0.88; 95% CI, 0.64 to 1.20; P=0.42). No reduction in total mortality was evident (hazard ratio in the intensive-therapy group, 1.05; 95% CI, 0.89 to 1.25; P=0.54; median follow-up, 11.8 years).

CONCLUSIONS

After nearly 10 years of follow-up, patients with type 2 diabetes who had been randomly assigned to intensive glucose control for 5.6 years had 8.6 fewer major cardiovascular events per 1000 person-years than those assigned to standard therapy, but no improvement was seen in the rate of overall survival. (Funded by the VA Cooperative Studies Program and others; VADT ClinicalTrials.gov number, NCT00032487.).

Cumulative incidence of death and rehospitalization among the elderly in the first year after NSTEMI

BACKGROUND

Age is associated with outcomes in non-ST-segment elevation myocardial infarction; however, less is known about rehospitalization or death among elderly survivors. We aimed to evaluate mortality and cause-specific rehospitalization rates in this growing population of older adults with ischemic heart disease.

METHODS

We linked 36,711 patients aged ≥65 years who survived an index non-ST-segment elevation myocardial infarction from the CRUSADE registry to Medicare claims data for follow-up. One-year survival estimates were compared by age group-65-79, 80-84, 85-89, and ≥90 years-and Cox models were used to analyze the association between age and 1-year mortality.

RESULTS

Death at 1 year increased markedly with age (from 13.3% for 65-79 years to 45.5% for ≥90 years). In contrast, rehospitalization rates at 1 year were similar and high across ages (65-79 years, 52.7%; ≥90 years, 56.5%), with nearly as many noncardiovascular-related as cardiovascular-related rehospitalizations. At 1 year, nonagenarians had substantially higher rates of death with or without preceding rehospitalization and twice the adjusted mortality than the group aged 65-79 years.

CONCLUSIONS

Evolving care delivery models should consider the high mortality in older adults after a non-ST-segment elevation myocardial infarction. Contrary to expectations, rehospitalization rates do not rise substantially with advancing age, and rehospitalization is often for noncardiac diagnoses.

Increased risk of arterial thromboembolic events after Staphylococcus aureus bacteremia: A matched cohort study

OBJECTIVES

An association between infection and arterial thromboembolic events (ATE) has been suggested. Here we examined the risk of myocardial infarction (MI), stroke and other ATE after Staphylococcus aureus bacteremia (SAB).

METHODS

Danish register-based nation-wide observational cohort study between 1995 and 2008 with matched control subjects from the general population.

RESULTS

Within a year, 278 of 15,669 SAB patients and 2570 of 156,690 controls developed MI, stroke or another ATE. The incidence rates among SAB patients were highest within the first 30 days and decreased over a year. The adjusted relative risk of MI, stroke and other ATE during the first 30 days after SAB in patients compared to controls were 2.2 (95% CI: 1.6-3.1), 5.5 (95% CI: 3.8-8.3) and 15.5 (95% CI: 6.9-35), respectively. Compared to controls, the increased adjusted relative risk persisted for 30 days for MI, 180 days for stroke and one year for other ATE. Increasing age, hypertension, atrial flutter/fibrillation, prior ATE and endocarditis in SAB patients were associated with an increased risk of ATE.

CONCLUSIONS

SAB was associated with a short-term increased risk of ATE that persisted longer dependent on type of event. Studies are warranted to investigate treatment strategies to diminish ATE after SAB.

Accuracy of clinician-clinical coder information handover following acute medical admissions: implication for using administrative datasets in clinical outcomes management

BACKGROUND

We evaluated the accuracy, limitations and potential sources of improvement in the clinical utility of the administrative dataset for acute medicine admissions.

METHODS

Accuracy of clinical coding in 8888 patient discharges following an emergency medical hospital admission to a teaching hospital and a district hospital over 3 years was ascertained by a coding accuracy audit team in respect of the primary and secondary diagnoses, morbidities and financial variance.

RESULTS

There was at least one change to the original coding in 4889 admissions (55%) and to the primary diagnosis of at least one finished consultant episodes of 1496 spells (16.8%). There were significant changes in the number of secondary diagnoses and the Charlson morbidity index following the audit. Charlson score increased in 8.2% and decreased in 2.3% of patients. An income variance of £816 977 (+5.0%) or £91.92 per patient was observed.

CONCLUSIONS

The importance and applications of coded healthcare big data within the NHS is increasing. The accuracy of coding is dependent on high-fidelity information transfer between clinicians and coders, which is prone to subjectivity, variability and error. We recommend greater involvement of clinicians as part of multidisciplinary teams to improve data accuracy, and urgent action to improve abstraction and clarity of assignment of strategic diagnoses like pneumonia and renal failure.

Cost-effectiveness and population impact of statins for primary prevention in adults aged 75 years or older in the United States

BACKGROUND

Evidence to guide primary prevention in adults aged 75 years or older is limited.

OBJECTIVE

To project the population impact and cost-effectiveness of statin therapy in adults aged 75 years or older.

DESIGN

Forecasting study using the Cardiovascular Disease Policy Model, a Markov model.

DATA SOURCES

Trial, cohort, and nationally representative data sources.

TARGET POPULATION

U.S. adults aged 75 to 94 years.

TIME HORIZON

10 years.

PERSPECTIVE

Health care system.

INTERVENTION

Statins for primary prevention based on low-density lipoprotein cholesterol threshold of 4.91 mmol/L (190 mg/dL), 4.14 mmol/L (160 mg/dL), or 3.36 mmol/L (130 mg/dL); presence of diabetes; or 10-year risk score of at least 7.5%.

OUTCOME MEASURES

Myocardial infarction (MI), coronary heart disease (CHD) death, disability-adjusted life-years, and costs.

RESULTS OF BASE-CASE ANALYSIS

All adults aged 75 years or older in the National Health and Nutrition Examination Survey have a 10-year risk score greater than 7.5%. If statins had no effect on functional limitation or cognitive impairment, all primary prevention strategies would prevent MIs and CHD deaths and be cost-effective. Treatment of all adults aged 75 to 94 years would result in 8 million additional users and prevent 105 000 (4.3%) incident MIs and 68 000 (2.3%) CHD deaths at an incremental cost per disability-adjusted life-year of $25 200.

RESULTS OF SENSITIVITY ANALYSIS

An increased relative risk for functional limitation or mild cognitive impairment of 1.10 to 1.29 could offset the cardiovascular benefits.

LIMITATION

Limited trial evidence targeting primary prevention in adults aged 75 years or older.

CONCLUSION

At effectiveness similar to that in trials, statins are projected to be cost-effective for primary prevention; however, even a small increase in geriatric-specific adverse effects could offset the cardiovascular benefit. Improved data on the potential benefits and harms of statins are needed to inform decision making.

PRIMARY FUNDING SOURCE

American Heart Association Western States Affiliate, National Institute on Aging, and the National Institute for Diabetes on Digestive and Kidney Diseases.

HIV infection, cardiovascular disease risk factor profile, and risk for acute myocardial infarction

BACKGROUND

Traditional cardiovascular disease risk factors (CVDRFs) increase the risk of acute myocardial infarction (AMI) among HIV-infected (HIV+) participants. We assessed the association between HIV and incident AMI within CVDRF strata.

METHODS

Cohort-81,322 participants (33% HIV+) without prevalent CVD from the Veterans Aging Cohort Study Virtual Cohort (prospective study of HIV+ and matched HIV- veterans) participated in this study. Veterans were followed from first clinical encounter on/after April 1, 2003, until AMI/death/last follow-up date (December 31, 2009). Predictors-HIV, CVDRFs (total cholesterol, cholesterol-lowering agents, blood pressure, blood pressure medication, smoking, diabetes) used to create 6 mutually exclusive profiles: all CVDRFs optimal, 1+ nonoptimal CVDRFs, 1+ elevated CVDRFs, and 1, 2, 3+ major CVDRFs. Outcome-Incident AMI [defined using enzyme, electrocardiogram (EKG) clinical data, 410 inpatient ICD-9 (Medicare), and/or death certificates]. Statistics-Cox models adjusted for demographics, comorbidity, and substance use.

RESULTS

Of note, 858 AMIs (42% HIV+) occurred over 5.9 years (median). Prevalence of optimal cardiac health was <2%. Optimal CVDRF profile was associated with the lowest adjusted AMI rates. Compared with HIV- veterans, AMI rates among HIV+ veterans with similar CVDRF profiles were higher. Compared with HIV- veterans without major CVDRFs, HIV+ veterans without major CVDRFs had a 2-fold increased risk of AMI (HR: 2.0; 95% confidence interval: 1.0 to 3.9; P = 0.044).

CONCLUSIONS

The prevalence of optimal cardiac health is low in this cohort. Among those without major CVDRFs, HIV+ veterans have twice the AMI risk. Compared with HIV- veterans with high CVDRF burden, AMI rates were still higher in HIV+ veterans. Preventing/reducing CVDRF burden may reduce excess AMI risk among HIV+ people.

Detecting clinically meaningful biomarkers with repeated measurements: An illustration with electronic health records

Data sources with repeated measurements are an appealing resource to understand the relationship between changes in biological markers and risk of a clinical event. While longitudinal data present opportunities to observe changing risk over time, these analyses can be complicated if the measurement of clinical metrics is sparse and/or irregular, making typical statistical methods unsuitable. In this article, we use electronic health record (EHR) data as an example to present an analytic procedure to both create an analytic sample and analyze the data to detect clinically meaningful markers of acute myocardial infarction (MI). Using an EHR from a large national dialysis organization we abstracted the records of 64,318 individuals and identified 4769 people that had an MI during the study period. We describe a nested case-control design to sample appropriate controls and an analytic approach using regression splines. Fitting a mixed-model with truncated power splines we perform a series of goodness-of-fit tests to determine whether any of 11 regularly collected laboratory markers are useful clinical predictors. We test the clinical utility of each marker using an independent test set. The results suggest that EHR data can be easily used to detect markers of clinically acute events. Special software or analytic tools are not needed, even with irregular EHR data.

Testosterone therapy and cardiovascular risk: advances and controversies

Two recent studies raised new concerns regarding cardiovascular (CV) risks with testosterone (T) therapy. This article reviews those studies as well as the extensive literature on T and CV risks. A MEDLINE search was performed for the years 1940 to August 2014 using the following key words: testosterone, androgens, human, male, cardiovascular, stroke, cerebrovascular accident, myocardial infarction, heart attack, death, and mortality. The weight and direction of evidence was evaluated and level of evidence (LOE) assigned. Only 4 articles were identified that suggested increased CV risks with T prescriptions: 2 retrospective analyses with serious methodological limitations, 1 placebo-controlled trial with few major adverse cardiac events, and 1 meta-analysis that included questionable studies and events. In contrast, several dozen studies have reported a beneficial effect of normal T levels on CV risks and mortality. Mortality and incident coronary artery disease are inversely associated with serum T concentrations (LOE IIa), as is severity of coronary artery disease (LOE IIa). Testosterone therapy is associated with reduced obesity, fat mass, and waist circumference (LOE Ib) and also improves glycemic control (LOE IIa). Mortality was reduced with T therapy in 2 retrospective studies. Several RCTs in men with coronary artery disease or heart failure reported improved function in men who received T compared with placebo. The largest meta-analysis to date revealed no increase in CV risks in men who received T and reduced CV risk among those with metabolic disease. In summary, there is no convincing evidence of increased CV risks with T therapy. On the contrary, there appears to be a strong beneficial relationship between normal T and CV health that has not yet been widely appreciated.

Testosterone therapy and risk of myocardial infarction: a pharmacoepidemiologic study

BACKGROUND

Recent studies have provided conflicting and controversial results about the risk of cardiovascular events, including myocardial infarction (MI), with testosterone replacement therapy (TRT). The potential adverse effects of different TRT formulations and duration of therapy on MI risk are unknown.

METHODS

We performed a case-control study within a cohort of 934,283 men aged 45-80 from the IMS LifeLink Health Plan Claims Database. For each case of MI, four controls were identified using density-based sampling. Rate ratios (RRs) were computed for current and past TRT users. As a sensitivity analysis, the risk of MI before and after the start of a first-time TRT prescription in the same patient was also computed.

RESULTS

We identified 30,066 MI cases and 120,264 corresponding controls. Current use of TRT was not associated with an increased risk of MI (RR 1.01, 95% confidence interval [CI] 0.89-1.16); first-time users did show an increased risk (RR 1.41, 95% CI 1.06-1.87; number needed to harm 305). There was no association between MI and past TRT users and no differences among the different formulations. The RRs for current use and first-time use of TRT in men with a previous history of coronary artery disease were 1.05 (95% CI 0.79-1.41) and 1.78 (95% CI 0.93-3.40), respectively.

CONCLUSION

In this large observational study, an association between MI and past or current TRT use was not found. However, a statistically significant association was observed between first-time TRT exposure and MI, although the absolute risk was low.

Capitalizing on prescribing pattern variation to compare medications for type 2 diabetes

BACKGROUND

Clinical trials often compare hypoglycemic medications on the basis of glycemic control but do not examine long-term outcomes (e.g., mortality). This study demonstrates an alternative approach to lengthening clinical trials to assess these long-term outcomes.

OBJECTIVE

To use observational quasi-experimental methods using instrumental variables (IVs) to compare the effect of two hypoglycemic medications, sulfonylureas (SUs) and thiazolidinediones (TZDs), on long-term outcomes.

METHODS

This study used administrative data from the Veterans Health Administration and Medicare from 2000 to 2010. The study population included US veterans dually enrolled in Medicare who received a prescription for metformin and then initiated SUs or TZDs. Patients could either continue on or discontinue metformin after the initiation of the second agent. Treatment was defined as starting either a SU or a TZD. Local variations in SU prescribing rates were used as instruments in IV models to control for selection bias. Survival models predicted all-cause mortality, ambulatory care sensitive condition hospitalizations, and stroke or heart attack (acute myocardial infarction).

RESULTS

Starting on SUs compared to TZDs significantly increased the likelihood of experiencing mortality and ACSC hospitalization. The estimated hazard ratio for the effect of starting on SUs compared to TZDs was 1.50 (95% confidence interval [CI] 1.09-2.09) for all-cause mortality, 1.68 (95% CI 1.31-2.15) for ambulatory care sensitive condition hospitalization, and 1.15 (95% CI 0.80-1.66) for acute myocardial infarction or stroke.

CONCLUSIONS

Our findings suggest increased risk of major adverse events associated with SUs as a second-line agent. Quasi-experimental IV methods may be an important alternative to lengthening clinical trials to assess long-term outcomes.

Cardiovascular, bleeding, and mortality risks in elderly Medicare patients treated with dabigatran or warfarin for nonvalvular atrial fibrillation

BACKGROUND

The comparative safety of dabigatran versus warfarin for treatment of nonvalvular atrial fibrillation in general practice settings has not been established.

METHODS AND RESULTS

We formed new-user cohorts of propensity score-matched elderly patients enrolled in Medicare who initiated dabigatran or warfarin for treatment of nonvalvular atrial fibrillation between October 2010 and December 2012. Among 134 414 patients with 37 587 person-years of follow-up, there were 2715 primary outcome events. The hazard ratios (95% confidence intervals) comparing dabigatran with warfarin (reference) were as follows: ischemic stroke, 0.80 (0.67-0.96); intracranial hemorrhage, 0.34 (0.26-0.46); major gastrointestinal bleeding, 1.28 (1.14-1.44); acute myocardial infarction, 0.92 (0.78-1.08); and death, 0.86 (0.77-0.96). In the subgroup treated with dabigatran 75 mg twice daily, there was no difference in risk compared with warfarin for any outcome except intracranial hemorrhage, in which case dabigatran risk was reduced. Most patients treated with dabigatran 75 mg twice daily appeared not to have severe renal impairment, the intended population for this dose. In the dabigatran 150-mg twice daily subgroup, the magnitude of effect for each outcome was greater than in the combined-dose analysis.

CONCLUSIONS

In general practice settings, dabigatran was associated with reduced risk of ischemic stroke, intracranial hemorrhage, and death and increased risk of major gastrointestinal hemorrhage compared with warfarin in elderly patients with nonvalvular atrial fibrillation. These associations were most pronounced in patients treated with dabigatran 150 mg twice daily, whereas the association of 75 mg twice daily with study outcomes was indistinguishable from warfarin except for a lower risk of intracranial hemorrhage with dabigatran.

Rate of percutaneous coronary intervention for the management of acute coronary syndromes and stable coronary artery disease in the United States (2007 to 2011)

Although the benefit of percutaneous coronary interventions (PCIs) for patients presenting with acute coronary syndromes (ACS) has been established in numerous studies, the role of PCI in stable coronary artery disease (CAD) remains controversial. With the publication of the Clinical Outcomes Utilizing Revascularization and Aggressive Drug Evaluations trial and the appropriate use criteria for coronary artery revascularization, we sought to examine the impact of these treatment strategies and guidelines on the current practice of PCI in United States. We conducted a serial cross-sectional study with time trends of patients undergoing PCI for ACS and stable CAD from 2007 to 2011. The annual rate of all PCI decreased by 27.7% from 10,785 procedures per million adults per year in 2007 to 2008 to 7,801 procedures per million adults per year in 2010 to 2011 (p=0.03). Although there was no statistically significant decrease in the PCI utilization for ACS from 2007 to 2011, PCI utilization for stable CAD decreased by 51.7% (from 2,056 procedures per million adults per year in 2008 to 992 procedures per million adults per year in 2011, p=0.02). Hospitals with a higher volume of PCI experienced a more significant decrease. Decrease in PCI utilization for stable CAD was statistically significant for patients with Medicare and private insurance/health maintenance organization (44.5%, p=0.03 and 59.5%, p=0.007, respectively). In conclusion, the rate of PCI decreased substantially starting from 2009 in the United States. Most of the decrease was attributed to the reduction in PCI utilization for stable CAD.

Hospital and emergency department factors associated with variations in missed diagnosis and costs for patients age 65 years and older with acute myocardial infarction who present to emergency departments

OBJECTIVES

The objective was to measure the variation in missed diagnosis and costs of care for older acute myocardial infarction (AMI) patients presenting to emergency departments (EDs) and to identify the hospital and ED characteristics associated with this variation.

METHODS

Using 2004-2005 Medicare inpatient and outpatient records, the authors identified a cohort of AMI patients age 65 years and older who presented to the ED for initial care. The primary outcome was missed diagnosis of AMI, i.e., AMI hospital admission within 7 days of an ED discharge for a condition suggestive of cardiac ischemia. Costs were defined as Medicare hospital payments for all services associated with and immediately resulting from the ED evaluation. The effect of ED and hospital characteristics on quality and costs were estimated using multilevel models with hospital random effects.

RESULTS

There were 371,638 AMI patients age 65 and older included in the study, of whom 4,707 were discharged home from their initial ED visits and subsequently admitted to the hospital. The median unadjusted hospital-level missed diagnosis percentage was 0.52% (interquartile range [IQR] = 0 to 3.45%). ED characteristics protective of adverse outcomes include higher ED chest pain acuity (adjusted odds ratio [aOR] = 0.23, 99% confidence interval [CI] = 0.19 to 0.27) and American Board of Emergency Medicine (ABEM) certification (aOR = 0.60, 99% CI = 0.50 to 0.73). Protective hospital characteristics include larger hospital size (aOR = 0.46, 99% CI = 0.37 to 0.57) and academic status (aOR = 0.74, 99% CI = 0.58 to 0.94). All of these characteristics were associated with higher costs as well.

CONCLUSIONS

The proportion of missed AMI diagnoses and cost of care for patients age 65 years and older presenting to EDs with AMI varies across hospitals. Hospitals with more board-certified emergency physicians (EPs) and higher average acuity are associated with significantly higher quality. All hospital characteristics associated with better ED outcomes are associated with higher costs.

Validation of acute myocardial infarction cases in the national health insurance research database in taiwan

Background

The aim of this study was to determine the validity of acute myocardial infarction (AMI) diagnosis coding in the National Health Insurance Research Database (NHIRD) by cross-comparisons of discharge diagnoses listed in the NHIRD with those in the medical records obtained from a medical center in Taiwan.

Methods

This was a cross-sectional study comparing records in the NHIRD and discharge notes in one medical center (DNMC) in the year 2008. Positive predictive values (PPVs) for AMI diagnoses were evaluated by reviewing the relevant clinical and laboratory data recorded in the discharge notes of the medical center. Agreement in comorbidities, cardiac procedures, and antiplatelet agent (aspirin or clopidogrel) prescriptions between the two databases was evaluated.

Results

We matched 341 cases of AMI hospitalizations from the two databases, and 338 cases underwent complete chart review. Of these 338 AMI cases, 297 were confirmed with clinical and lab data, which yielded a PPV of 0.88. The consistency rate for coronary intervention, stenting, and antiplatelet prescription at admission was high, yielding a PPV over 0.90. The percentage of consistency in comorbidity diagnoses was 95.9% (324/338) among matched AMI cases.

Conclusions

The NHIRD appears to be a valid resource for population research in cardiovascular diseases.

Systems pharmacology of adverse event mitigation by drug combinations

Drugs are designed for therapy, but medication-related adverse events are common, and risk/benefit analysis is critical for determining clinical use. Rosiglitazone, an efficacious antidiabetic drug, is associated with increased myocardial infarctions (MIs), thus limiting its usage. Because diabetic patients are often prescribed multiple drugs, we searched for usage of a second drug ("drug B") in the Food and Drug Administration's Adverse Event Reporting System (FAERS) that could mitigate the risk of rosiglitazone ("drug A")-associated MI. In FAERS, rosiglitazone usage is associated with increased occurrence of MI, but its combination with exenatide significantly reduces rosiglitazone-associated MI. Clinical data from the Mount Sinai Data Warehouse support the observations from FAERS. Analysis for confounding factors using logistic regression showed that they were not responsible for the observed effect. Using cell biological networks, we predicted that the mitigating effect of exenatide on rosiglitazone-associated MI could occur through clotting regulation. Data we obtained from the db/db mouse model agreed with the network prediction. To determine whether polypharmacology could generally be a basis for adverse event mitigation, we analyzed the FAERS database for other drug combinations wherein drug B reduced serious adverse events reported with drug A usage such as anaphylactic shock and suicidality. This analysis revealed 19,133 combinations that could be further studied. We conclude that this type of crowdsourced approach of using databases like FAERS can help to identify drugs that could potentially be repurposed for mitigation of serious adverse events.

Adherence to dabigatran therapy and longitudinal patient outcomes: insights from the veterans health administration

BACKGROUND

Dabigatran is a novel oral anti-coagulant (NOAC) that reduces risk of stroke in patients with non-valvular atrial fibrillation (NVAF). It does not require routine monitoring with laboratory testing which may have an adverse impact on adherence. We aimed to describe adherence to dabigatran in the first year after initiation and assess the association between non-adherence to dabigatran and clinical outcomes in a large integrated healthcare system.

METHODS

We studied a national cohort of 5,376 patients with NVAF, initiated on dabigatran between October-2010 and September-2012 at all Veterans Affairs hospitals. Adherence to dabigatran was calculated as proportion of days covered (PDC) and association between PDC and outcomes was assessed using standard regression techniques.

RESULTS

Mean age of the study cohort was 71.3 ± 9.7 years; 98.3% were men and mean CHADS2 score was 2.4 ± 1.2 (mean CHA2DS2VASc score 3.2 ± 1.4). Median PDC was 94% (IQR 76%-100%; mean PDC 84% ± 22%) over a median follow-up of 244 days (IQR 140-351). A total of 1,494 (27.8%) patients had a PDC <80% and were classified as non-adherent. After multivariable adjustment, lower adherence was associated with increased risk for combined all-cause mortality and stroke (HR 1.13, 95% CI 1.07-1.19 per 10% decrease in PDC). Adherence to dabigatran was not associated with non-fatal bleeding or myocardial infarction.

CONCLUSIONS

In the year after initiation, adherence to dabigatran for a majority of patients is very good. However, 28% of patients in our cohort had poor adherence. Furthermore, lower adherence to dabigatran was associated with increased adverse outcomes. Concerted efforts are needed to optimize adherence to NOACs.

Testosterone, cardiovascular risk, and hormonophobia

INTRODUCTION

A public outcry against testosterone (T) therapy has suddenly occurred based on two reports suggesting treatment was associated with increased cardiovascular (CV) risks.

AIM

To analyze scientific and social bases for concerns regarding T therapy.

METHODS

Analysis of recent articles regarding CV risks with T and comparison with events surrounding publication of results of the Women's Health Initiative in 2002.

RESULTS

In the first study, the percentage of individuals with an adverse event was lower by half in men who received T compared with untreated men (10.1% vs. 21.2%). However, an opposite conclusion was reached via complex statistics. The second study reported minor increased rate of nonfatal myocardial infarction (MI) up to 90 days after receiving a T prescription compared with the prior 12 months. However, there was no control group, so it is unknown whether this MI rate was increased, reduced, or unchanged compared with untreated men. Neither study provided substantive evidence of risk, yet these were lauded as proof of dangers, despite a substantial literature to the contrary. Similar events followed the publication of the Women's Health Initiative in 2002 when a media frenzy over increased risks with female hormone replacement therapy obscured the fact that the reported excess risk was clinically meaningless, at two events per 1,000 person-years. Stakeholders driving concerns regarding hormone risks are unlikely to be clinicians with real-world patient experience.

CONCLUSIONS

The use of weak studies as proof of danger indicates that cultural (i.e., nonscientific) forces are at play. Negative media stories touting T's risks appear fueled by antipharma sentiment, anger against aggressive marketing, and antisexuality. This stance is best described as "hormonophobia." As history shows, evidence alone may be insufficient to alter a public narrative. The true outrage is that social forces and hysteria have combined to deprive men of a useful treatment without regard for medical science.

Epidemiology of pneumococcal disease in a national cohort of older adults

Introduction

Streptococcus pneumoniae is a major cause of morbidity and mortality. We sought to describe the epidemiology of non-invasive and invasive pneumococcal disease in a national Veterans Affairs population within the United States.

Methods

We conducted a retrospective study in older patients (aged ≥50 years) with positive pneumococcal cultures from any site between 2002 and 2011. We described outpatient and inpatient pneumococcal disease incidence per 100,000 clinic visits/hospitalizations. Repeat cultures within a 30-day period were considered to represent the same episode. To describe the epidemiology of serious pneumococcal infections (bacteremia, meningitis, pneumonia), we assessed demographics, clinical characteristics, and risk factors for S. pneumoniae. Pneumonia was defined as a positive respiratory culture with a pneumonia diagnosis code. Bacteremia and meningitis were identified from positive cultures. Generalized linear mixed models were used to quantify changes over time.

Results

Over the study period, we identified 45,983 unique episodes of pneumococcal disease (defined by positive cultures). Incidence decreased significantly by 3.5% per year in outpatients and increased non-significantly by 0.2% per year in inpatients. In 2011, the outpatient and inpatient incidence was 2.6 and 328.1 infections per 100,000 clinic visits/hospitalizations, respectively. Among inpatients with serious infections, chronic disease risk factors for pneumococcal disease increased significantly each year, including respiratory disease (1.9% annually), diabetes (1.3%), and renal failure (1.0%). Overall, 30.2% of inpatients with serious infections had a pneumococcal immunization in the previous 5 years. Invasive disease (37.4% versus 34.9%, P = 0.004) and mortality (14.0% versus 12.7%, P = 0.045) were higher in non-vaccinated patients compared to vaccinated patients.

Conclusions

In our national study of older adults, the baseline health status of those with serious pneumococcal infections worsened over the study period. As the population ages and the chronic disease epidemic grows, the burden of pneumococcal disease is likely to increase thus highlighting the importance of pneumococcal vaccination.

Electronic supplementary material

The online version of this article (doi:10.1007/s40121-014-0025-y) contains supplementary material, which is available to authorized users.

Creation and Validation of an EMR-based Algorithm for Identifying Major Adverse Cardiac Events while on Statins

Statin medications are often prescribed to ameliorate a patient's risk of cardiovascular events due in part to cholesterol reduction. We developed and evaluated an algorithm that can accurately identify subjects with major adverse cardiac events (MACE) while on statins using electronic medical record (EMR) data. The algorithm also identifies subjects experiencing their first MACE while on statins for primary prevention. The algorithm achieved 90% to 97% PPVs in identification of MACE cases as compared against physician review. By applying the algorithm to EMR data in BioVU, cases and controls were identified and used subsequently to replicate known associations with eight genetic variants. We replicated 6/8 previously reported genetic associations with cardiovascular diseases or lipid metabolism disorders. Our results demonstrated that the algorithm can be used to accurately identify subjects with MACE and MACE while on statins. Consequently, future e studies can be conducted to investigate and validate the relationship between statins and MACE using real-world clinical data.

Validity of myocardial infarction diagnoses in administrative databases: a systematic review

BACKGROUND

Though administrative databases are increasingly being used for research related to myocardial infarction (MI), the validity of MI diagnoses in these databases has never been synthesized on a large scale.

OBJECTIVE

To conduct the first systematic review of studies reporting on the validity of diagnostic codes for identifying MI in administrative data.

METHODS

MEDLINE and EMBASE were searched (inception to November 2010) for studies: (a) Using administrative data to identify MI; or (b) Evaluating the validity of MI codes in administrative data; and (c) Reporting validation statistics (sensitivity, specificity, positive predictive value (PPV), negative predictive value, or Kappa scores) for MI, or data sufficient for their calculation. Additonal articles were located by handsearch (up to February 2011) of original papers. Data were extracted by two independent reviewers; article quality was assessed using the Quality Assessment of Diagnostic Accuracy Studies tool.

RESULTS

Thirty studies published from 1984-2010 were included; most assessed codes from the International Classification of Diseases (ICD)-9th revision. Sensitivity and specificity of hospitalization data for identifying MI in most [≥50%] studies was ≥86%, and PPV in most studies was ≥93%. The PPV was higher in the more-recent studies, and lower when criteria that do not incorporate cardiac troponin levels (such as the MONICA) were employed as the gold standard. MI as a cause-of-death on death certificates also demonstrated lower accuracy, with maximum PPV of 60% (for definite MI).

CONCLUSIONS

Hospitalization data has higher validity and hence can be used to identify MI, but the accuracy of MI as a cause-of-death on death certificates is suboptimal, and more studies are needed on the validity of ICD-10 codes. When using administrative data for research purposes, authors should recognize these factors and avoid using vital statistics data if hospitalization data is not available to confirm deaths from MI.

Increased risk of non-fatal myocardial infarction following testosterone therapy prescription in men

BACKGROUND

An association between testosterone therapy (TT) and cardiovascular disease has been reported and TT use is increasing rapidly.

METHODS

We conducted a cohort study of the risk of acute non-fatal myocardial infarction (MI) following an initial TT prescription (N = 55,593) in a large health-care database. We compared the incidence rate of MI in the 90 days following the initial prescription (post-prescription interval) with the rate in the one year prior to the initial prescription (pre-prescription interval) (post/pre). We also compared post/pre rates in a cohort of men prescribed phosphodiesterase type 5 inhibitors (PDE5I; sildenafil or tadalafil, N = 167,279), and compared TT prescription post/pre rates with the PDE5I post/pre rates, adjusting for potential confounders using doubly robust estimation.

RESULTS

In all subjects, the post/pre-prescription rate ratio (RR) for TT prescription was 1.36 (1.03, 1.81). In men aged 65 years and older, the RR was 2.19 (1.27, 3.77) for TT prescription and 1.15 (0.83, 1.59) for PDE5I, and the ratio of the rate ratios (RRR) for TT prescription relative to PDE5I was 1.90 (1.04, 3.49). The RR for TT prescription increased with age from 0.95 (0.54, 1.67) for men under age 55 years to 3.43 (1.54, 7.56) for those aged ≥ 75 years (p trend = 0.03), while no trend was seen for PDE5I (p trend = 0.18). In men under age 65 years, excess risk was confined to those with a prior history of heart disease, with RRs of 2.90 (1.49, 5.62) for TT prescription and 1.40 (0.91, 2.14) for PDE5I, and a RRR of 2.07 (1.05, 4.11).

DISCUSSION

In older men, and in younger men with pre-existing diagnosed heart disease, the risk of MI following initiation of TT prescription is substantially increased.

Increased risk of non-fatal myocardial infarction following testosterone therapy prescription in men

Background

An association between testosterone therapy (TT) and cardiovascular disease has been reported and TT use is increasing rapidly.

Methods

We conducted a cohort study of the risk of acute non-fatal myocardial infarction (MI) following an initial TT prescription (N = 55,593) in a large health-care database. We compared the incidence rate of MI in the 90 days following the initial prescription (post-prescription interval) with the rate in the one year prior to the initial prescription (pre-prescription interval) (post/pre). We also compared post/pre rates in a cohort of men prescribed phosphodiesterase type 5 inhibitors (PDE5I; sildenafil or tadalafil, N = 167,279), and compared TT prescription post/pre rates with the PDE5I post/pre rates, adjusting for potential confounders using doubly robust estimation.

Results

In all subjects, the post/pre-prescription rate ratio (RR) for TT prescription was 1.36 (1.03, 1.81). In men aged 65 years and older, the RR was 2.19 (1.27, 3.77) for TT prescription and 1.15 (0.83, 1.59) for PDE5I, and the ratio of the rate ratios (RRR) for TT prescription relative to PDE5I was 1.90 (1.04, 3.49). The RR for TT prescription increased with age from 0.95 (0.54, 1.67) for men under age 55 years to 3.43 (1.54, 7.56) for those aged ≥75 years (p_trend = 0.03), while no trend was seen for PDE5I (p_trend = 0.18). In men under age 65 years, excess risk was confined to those with a prior history of heart disease, with RRs of 2.90 (1.49, 5.62) for TT prescription and 1.40 (0.91, 2.14) for PDE5I, and a RRR of 2.07 (1.05, 4.11).

Discussion

In older men, and in younger men with pre-existing diagnosed heart disease, the risk of MI following initiation of TT prescription is substantially increased.

Validation of Diagnostic and Procedural Codes for Identification of Acute Cardiovascular Events in US Veterans with Rheumatoid Arthritis

Objective:

To assess the accuracy of International Classification of Diseases, Ninth Revision, and Current Procedural Terminology codes for identifying cardiovascular (CV) events (myocardial infarction [MI], stroke, coronary artery bypass graft [CABG], and percutaneous coronary intervention [PCI]) in enrollees of the Veterans Affairs Rheumatoid Arthritis (VARA) registry.

Design:

We performed a validation study from VARA enrollment until 6/1/2010 to compare the accuracy of CV events in those with and without CV-event coding in inpatient and outpatient records to evaluate for CV events +/− 3 months of the coding. The positive predictive value (PPV) was calculated, and codes with a PPV ≥50% were included in a composite coding algorithm.

Results:

We evaluated 107 individuals for 21 CV-event codes and 60 individuals without CV-event coding. The PPV varied between 0–100%. Composite coding algorithms’ PPV ranged from 70–100%.

Conclusions:

Validation of these algorithms allows for identification of acute CV events with known accuracy. The sensitivity and PPV of coding algorithms for CABG and PCI exceed that of stroke and MI.

Changes in Geographic Variation in the Use of Percutaneous Coronary Intervention for Stable Ischemic Heart Disease After Publication of the Clinical Outcomes Utilizing Revascularization and Aggressive Drug Evaluation (COURAGE) Trial

Background—

Clinical uncertainty is cited as a cause of geographic variation. However, little is known about the effect of comparative effectiveness research on variation. We examined whether geographic variation in the use of percutaneous coronary intervention (PCI) for stable ischemic heart disease (SIHD) declined after publication of the Clinical Outcomes Utilizing Revascularization and Aggressive Drug Evaluation (COURAGE) trial.

Methods and Results—

We examined changes in utilization and geographic variation in 67 hospital referral regions using the State Inpatient Databases. We compared age- and sex-adjusted rates of PCI for SIHD before (2006) and after (2008) publication of the COURAGE trial and compared those with contemporaneous changes in PCI volume for acute coronary syndrome. A total of 272 659 PCIs for SIHD from 526 hospitals were included in the analysis. After the publication of the COURAGE trial, PCI volume for SIHD declined by 25% ( P <0.001) and decreased by 12% for acute coronary syndrome ( P <0.001). This was predominantly attributable to changes in hospital referral regions with the highest levels of utilization pre-COURAGE trial (35% decline in the highest tertile versus 18% in the lowest). As measured by the systematic component of variation, there was substantial geographic variation in the use of PCI for SIHD preceding the publication of the COURAGE trial. Variation declined by 28% (0.53 versus 0.40) after publication, but geographic variation remained higher for SIHD than acute coronary syndrome (0.40 versus 0.17).

Conclusions—

There was a substantial decline in the use of and geographic variation in PCI for SIHD after the publication of the COURAGE trial. However, geographic variation in the use of PCI for SIHD remained high.

A plasma long-chain acylcarnitine predicts cardiovascular mortality in incident dialysis patients

Background

The marked excess in cardiovascular mortality that results from uremia remains poorly understood.

Methods and Results

In 2 independent, nested case‐control studies, we applied liquid chromatography‐mass spectrometry‐based metabolite profiling to plasma obtained from participants of a large cohort of incident hemodialysis patients. First, 100 individuals who died of a cardiovascular cause within 1 year of initiating hemodialysis (cases) were randomly selected along with 100 individuals who survived for at least 1 year (controls), matched for age, sex, and race. Four highly intercorrelated long‐chain acylcarnitines achieved the significance threshold adjusted for multiple testing (P<0.0003). Oleoylcarnitine, the long‐chain acylcarnitine with the strongest association with cardiovascular mortality in unadjusted analysis, remained associated with 1‐year cardiovascular death after multivariable adjustment (odds ratio per SD 2.3 [95% confidence interval, 1.4 to 3.8]; P=0.001). The association between oleoylcarnitine and 1‐year cardiovascular death was then replicated in an independent sample (n=300, odds ratio per SD 1.4 [95% confidence interval, 1.1 to 1.9]; P=0.008). Addition of oleoylcarnitine to clinical variables improved cardiovascular risk prediction using net reclassification (NRI, 0.38 [95% confidence interval, 0.20 to 0.56]; P<0.0001). In physiologic profiling studies, we demonstrate that the fold change in plasma acylcarnitine levels from the aorta to renal vein and from pre‐ to post hemodialysis samples exclude renal or dialytic clearance of long‐chain acylcarnitines as confounders in our analysis.

Conclusions

Our data highlight clinically meaningful alterations in acylcarnitine homeostasis at the time of dialysis initiation, which may represent an early marker, effector, or both of uremic cardiovascular risk.

Cardiovascular and mortality risk in elderly Medicare beneficiaries treated with olmesartan versus other angiotensin receptor blockers

PURPOSE

In the randomized trial, Randomized Olmesartan and Diabetes Microalbuminuria Prevention, acute cardiovascular death was increased nearly fivefold in diabetic patients treated with high-dose olmesartan, an angiotensin receptor blocker (ARB), compared with placebo.

METHODS

Medicare beneficiaries were entered into new-user cohorts of olmesartan or other ARBs and followed on therapy for occurrence of acute myocardial infarction, stroke, or death. Analyses focused on specific subgroups defined by diabetes status, ARB dose, and duration of therapy. Hazard ratios (HR) with 95% confidence intervals (CIs) were estimated using Cox proportional hazards regression, with other ARBs as reference.

RESULTS

A total of 158,054 olmesartan and 724,673 other ARB users were followed for 54,285 and 260,390 person-years, respectively, during which 9237 endpoint events occurred. Lower-dose olmesartan was not associated with increased risk for any endpoint, regardless of duration of use. High-dose olmesartan for 6 months or longer was associated with increased risk of death in patients with diabetes (HR 2.03, 95%CI 1.09-3.75, p = 0.02) and with reduced risk in nondiabetic patients (HR 0.46, 95%CI 0.24-0.86, p = 0.01). Some, but not all, sensitivity analyses suggested that selective prescribing of olmesartan to healthier patients (channeling bias) may have accounted for the reduced risk in nondiabetic patients.

CONCLUSIONS

High-dose olmesartan was associated with an increased risk of death in diabetic patients treated for 6 months or longer and with a reduced risk of death in nondiabetic patients, when compared with use of other ARBs. This latter effect was probably because of selective prescribing of olmesartan to healthier patients, although effect modification cannot be excluded. Published 2013. This article is a U.S. Government work and is in the public domain in the USA.

Billing code algorithms to identify cases of peripheral artery disease from administrative data

Objective

To construct and validate billing code algorithms for identifying patients with peripheral arterial disease (PAD).

Methods

We extracted all encounters and line item details including PAD-related billing codes at Mayo Clinic Rochester, Minnesota, between July 1, 1997 and June 30, 2008; 22 712 patients evaluated in the vascular laboratory were divided into training and validation sets. Multiple logistic regression analysis was used to create an integer code score from the training dataset, and this was tested in the validation set. We applied a model-based code algorithm to patients evaluated in the vascular laboratory and compared this with a simpler algorithm (presence of at least one of the ICD-9 PAD codes 440.20–440.29). We also applied both algorithms to a community-based sample (n=4420), followed by a manual review.

Results

The logistic regression model performed well in both training and validation datasets (c statistic=0.91). In patients evaluated in the vascular laboratory, the model-based code algorithm provided better negative predictive value. The simpler algorithm was reasonably accurate for identification of PAD status, with lesser sensitivity and greater specificity. In the community-based sample, the sensitivity (38.7% vs 68.0%) of the simpler algorithm was much lower, whereas the specificity (92.0% vs 87.6%) was higher than the model-based algorithm.

Conclusions

A model-based billing code algorithm had reasonable accuracy in identifying PAD cases from the community, and in patients referred to the non-invasive vascular laboratory. The simpler algorithm had reasonable accuracy for identification of PAD in patients referred to the vascular laboratory but was significantly less sensitive in a community-based sample.

Prehypertension, hypertension, and the risk of acute myocardial infarction in HIV-infected and -uninfected veterans

BACKGROUND

Compared to uninfected people, human immunodeficiency virus (HIV)-infected individuals may have an increased risk of acute myocardial infarction (AMI). Currently, HIV-infected people are treated to the same blood pressure (BP) goals (<140/90 or <130/80 mm Hg) as their uninfected counterparts. Whether HIV-infected people with elevated BP have excess AMI risk compared to uninfected people is not known. This study examines whether the association between elevated BP and AMI risk differs by HIV status.

METHODS

The Veterans Aging Cohort Study Virtual Cohort (VACS VC) consists of HIV-infected and -uninfected veterans matched 1:2 on age, sex, race/ethnicity, and clinical site. For this analysis, we analyzed 81 026 people with available BP data from VACS VC, who were free of cardiovascular disease at baseline. BP was the average of the 3 routine outpatient clinical measurements performed closest to baseline (first clinical visit after April 2003). BP categories used in the analyses were based on criteria of the Seventh Report of the Joint National Committee on Prevention, Detection, Evaluation, and Treatment of High Blood Pressure. Analyses were performed using Cox proportional hazards regression.

RESULTS

Over 5.9 years (median), 860 incident AMIs occurred. Low/high prehypertensive and untreated/treated hypertensive HIV-infected individuals had increased AMI risk compared to uninfected, untreated normotensive individuals (hazard ratio [HR], 1.60 [95% confidence interval {CI}, 1.07-2.39]; HR, 1.81 [95% CI, 1.22-2.68]; HR, 2.57 [95% CI, 1.76-3.76]; and HR, 2.76 [95% CI, 1.90-4.02], respectively).

CONCLUSIONS

HIV, prehypertensive BP, and hypertensive BP were associated with an increased risk of AMI in a cohort of HIV-infected and -uninfected veterans. Future studies should prospectively investigate whether HIV interacts with BP to further increase AMI risk.

Implementing randomized effectiveness trials in large insurance systems

BACKGROUND

The need to identify how best to structure health insurance and to deliver health care services is a central priority for comparative effectiveness research. Studies designed to evaluate these issues are frequently conducted in large insurance systems. We sought to describe the challenges faced when conducting trials in this context.

METHODS

Using the Post-Myocardial Infarction Free Rx Event and Economic Evaluation (MI FREEE) trial as an example, we describe the methodological and practical challenges of conducting trials in large insurance systems.

RESULTS

We encountered six key challenges while conducting MI FREEE trial, namely the need to obtain plan sponsor permission to experiment, the desire of plan sponsors to have all of their beneficiaries receive the same intervention, the inaccuracy of claims-based identification methods and the impact of claims lag on the timely enrollment of potentially eligible patients, the reluctance of patients to participate in insurance-based interventions and the potential need for informed consent, the frequent introduction of new cointerventions in real-world delivery systems, and the high rates of loss to follow-up because of insurance "churn." We describe the approaches we used to overcome these challenges.

CONCLUSIONS

Studies in insurance settings are a powerful and necessary design for evaluating comparative effectiveness interventions. There are numerous strategies to address the potential logistical and methodological challenges that this research environment uniquely creates.

Identification of acute myocardial infarction from electronic healthcare records using different disease coding systems: a validation study in three European countries

OBJECTIVE

To evaluate positive predictive value (PPV) of different disease codes and free text in identifying acute myocardial infarction (AMI) from electronic healthcare records (EHRs).

DESIGN

Validation study of cases of AMI identified from general practitioner records and hospital discharge diagnoses using free text and codes from the International Classification of Primary Care (ICPC), International Classification of Diseases 9th revision-clinical modification (ICD9-CM) and ICD-10th revision (ICD-10).

SETTING

Population-based databases comprising routinely collected data from primary care in Italy and the Netherlands and from secondary care in Denmark from 1996 to 2009.

PARTICIPANTS

A total of 4 034 232 individuals with 22 428 883 person-years of follow-up contributed to the data, from which 42 774 potential AMI cases were identified. A random sample of 800 cases was subsequently obtained for validation.

MAIN OUTCOME MEASURES

PPVs were calculated overall and for each code/free text. 'Best-case scenario' and 'worst-case scenario' PPVs were calculated, the latter taking into account non-retrievable/non-assessable cases. We further assessed the effects of AMI misclassification on estimates of risk during drug exposure.

RESULTS

Records of 748 cases (93.5% of sample) were retrieved. ICD-10 codes had a 'best-case scenario' PPV of 100% while ICD9-CM codes had a PPV of 96.6% (95% CI 93.2% to 99.9%). ICPC codes had a 'best-case scenario' PPV of 75% (95% CI 67.4% to 82.6%) and free text had PPV ranging from 20% to 60%. Corresponding PPVs in the 'worst-case scenario' all decreased. Use of codes with lower PPV generally resulted in small changes in AMI risk during drug exposure, but codes with higher PPV resulted in attenuation of risk for positive associations.

CONCLUSIONS

ICD9-CM and ICD-10 codes have good PPV in identifying AMI from EHRs; strategies are necessary to further optimise utility of ICPC codes and free-text search. Use of specific AMI disease codes in estimation of risk during drug exposure may lead to small but significant changes and at the expense of decreased precision.

Differentiation of ileostomy from colostomy procedures: assessing the accuracy of current procedural terminology codes and the utility of natural language processing

BACKGROUND

Large databases provide a wealth of information for researchers, but identifying patient cohorts often relies on the use of current procedural terminology (CPT) codes. In particular, studies of stoma surgery have been limited by the accuracy of CPT codes in identifying and differentiating ileostomy procedures from colostomy procedures. It is important to make this distinction because the prevalence of complications associated with stoma formation and reversal differ dramatically between types of stoma. Natural language processing (NLP) is a process that allows text-based searching. The Automated Retrieval Console is an NLP-based software that allows investigators to design and perform NLP-assisted document classification. In this study, we evaluated the role of CPT codes and NLP in differentiating ileostomy from colostomy procedures.

METHODS

Using CPT codes, we conducted a retrospective study that identified all patients undergoing a stoma-related procedure at a single institution between January 2005 and December 2011. All operative reports during this time were reviewed manually to abstract the following variables: formation or reversal and ileostomy or colostomy. Sensitivity and specificity for validation of the CPT codes against the mastery surgery schedule were calculated. Operative reports were evaluated by use of NLP to differentiate ileostomy- from colostomy-related procedures. Sensitivity and specificity for identifying patients with ileostomy or colostomy procedures were calculated for CPT codes and NLP for the entire cohort.

RESULTS

CPT codes performed well in identifying stoma procedures (sensitivity 87.4%, specificity 97.5%). A total of 664 stoma procedures were identified by CPT codes between 2005 and 2011. The CPT codes were adequate in identifying stoma formation (sensitivity 97.7%, specificity 72.4%) and stoma reversal (sensitivity 74.1%, specificity 98.7%), but they were inadequate in identifying ileostomy (sensitivity 35.0%, specificity 88.1%) and colostomy (75.2% and 80.9%). NLP performed with greater sensitivity, specificity, and accuracy than CPT codes in identifying stoma procedures and stoma types. Major differences where NLP outperformed CPT included identifying ileostomy (specificity 95.8%, sensitivity 88.3%, and accuracy 91.5%) and colostomy (97.6%, 90.5%, and 92.8%, respectively).

CONCLUSION

CPT codes can identify effectively patients who have had stoma procedures and are adequate in distinguishing between formation and reversal; however, CPT codes cannot differentiate ileostomy from colostomy. NLP can be used to differentiate between ileostomy- and colostomy-related procedures. The role of NLP in conjunction with electronic medical records in data retrieval warrants further investigation.

Cardiovascular and mortality risks in Parkinson's disease patients treated with entacapone

The controlled trial Stalevo Reduction in Dyskinesia Evaluation in Parkinson's Disease (STRIDE-PD) reported an unexpected increase in acute myocardial infarction (AMI) with entacapone use in patients with Parkinson's disease (PD). The authors investigated whether entacapone increased cardiovascular and mortality risk compared with the use of a non-levodopa dopamine agonist (DA) or a selective monoamine oxidase type-B inhibitor (MAOBI). Using national Medicare data, a new-user cohort of elderly patients with PD treated with entacapone was propensity score (PS) matched with new users of either DA or MAOBI. The PS model included variables for sociodemographics, cardiovascular disease, medications, prior PD treatment, and comorbidities. Cox proportional hazards regression was used to compare on-therapy time to event for AMI, stroke, and death with DA-MAOBI as a reference. Study cohorts included 8681 entacapone-treated and 17,362 DA-MAOBI-treated initators who were followed for 2569 and 5385 person-years, respectively. Cohorts were closely balanced for all covariates. During follow-up, there were 106 AMIs, 89 strokes, and 201 deaths. The hazard ratio (HR) and 95% confidence interval (CI) associated with entacapone use was 0.86 (95% CI, 0.57-1.30) for AMI, 0.85 (95% CI, 0.54-1.35) for stroke, and 0.79 (95% CI, 0.58-1.07) for death. The risk was unchanged for treatment of ≤ 6 months' and>6 months' duration and was unaffected by adjustment for time-varying levodopa use during follow-up. The risk of each endpoint was not differentially affected by diabetes, ischemic heart disease, or kidney failure status. However, the risk of stroke was modified by the presence (HR, 2.09; 95% CI, 0.98-4.45) or absence (HR, 0.51; 95% CI, 0.27-0.95) of advanced PD-related morbidities (P value for interaction=0.004). Entacapone was not associated with an increased risk of AMI, stroke, or death in elderly patients with PD.

Amphetamines, atomoxetine and the risk of serious cardiovascular events in adults

Main Objective

To compare the incidence rates of serious cardiovascular events in adult initiators of amphetamines or atomoxetine to rates in non-users.

Methods

This was a retrospective cohort study of new amphetamines (n = 38,586) or atomoxetine (n = 20,995) users. Each medication user was matched to up to four non-users on age, gender, data source, and state (n = 238,183). The following events were primary outcomes of interest 1) sudden death or ventricular arrhythmia, 2) stroke, 3) myocardial infarction, 4) a composite endpoint of stroke or myocardial infarction. Cox proportional hazard regression was used to calculate propensity-adjusted hazard ratios for amphetamines versus matched non-users and atomoxetine versus matched non-users, with intracluster dependence within matched sets accounted for using a robust sandwich estimator.

Results

The propensity-score adjusted hazard ratio for amphetamines use versus non-use was 1.18 (95% CI: 0.55–2.54) for sudden death/ventricular arrhythmia, 0.80 (95% CI: 0.44–1.47) for stroke, 0.75 (95% CI: 0.42–1.35) for myocardial infarction, and 0.78 (95% CI: 0.51–1.19) for stroke/myocardial infarction. The propensity-score adjusted hazard ratio for atomoxetine use versus non-use was 0.41 (95% CI: 0.10–1.75) for sudden death/ventricular arrhythmia, 1.30 (95% CI: 0.52–3.29) for stroke, 0.56 (95% CI: 0.16–2.00) for myocardial infarction, and 0.92 (95% CI: 0.44–1.92) for stroke/myocardial infarction.

Conclusions

Initiation of amphetamines or atomoxetine was not associated with an elevated risk of serious cardiovascular events. However, some of the confidence intervals do not exclude modest elevated risks, e.g. for sudden death/ventricular arrhythmia.

Validation of acute myocardial infarction in the Food and Drug Administration's Mini-Sentinel program

PURPOSE

To validate an algorithm based upon International Classification of Diseases, 9(th) revision, Clinical Modification (ICD-9-CM) codes for acute myocardial infarction (AMI) documented within the Mini-Sentinel Distributed Database (MSDD).

METHODS

Using an ICD-9-CM-based algorithm (hospitalized patients with 410.x0 or 410.x1 in primary position), we identified a random sample of potential cases of AMI in 2009 from four Data Partners participating in the Mini-Sentinel Program. Cardiologist reviewers used information abstracted from hospital records to assess the likelihood of an AMI diagnosis based on criteria from the Joint European Society of Cardiology and American College of Cardiology Global Task Force. Positive predictive values (PPVs) of the ICD-9-based algorithm were calculated.

RESULTS

Of the 153 potential cases of AMI identified, hospital records for 143 (93%) were retrieved and abstracted. Overall, the PPV was 86.0% (95% confidence interval; 79.2%, 91.2%). PPVs ranged from 76.3% to 94.3% across the four Data Partners.

CONCLUSIONS

The overall PPV of potential AMI cases, as identified using an ICD-9-CM-based algorithm, may be acceptable for safety surveillance; however, PPVs do vary across Data Partners. This validation effort provides a contemporary estimate of the reliability of this algorithm for use in future surveillance efforts conducted using the Food and Drug Administration's MSDD.

Comparative effectiveness of sulfonylurea and metformin monotherapy on cardiovascular events in type 2 diabetes mellitus: a cohort study

BACKGROUND

The effects of sulfonylureas and metformin on outcomes of cardiovascular disease (CVD) in type 2 diabetes are not well-characterized.

OBJECTIVE

To compare the effects of sulfonylureas and metformin on CVD outcomes (acute myocardial infarction and stroke) or death.

DESIGN

Retrospective cohort study.

SETTING

National Veterans Health Administration databases linked to Medicare files.

PATIENTS

Veterans who initiated metformin or sulfonylurea therapy for diabetes. Patients with chronic kidney disease or serious medical illness were excluded.

MEASUREMENTS

Composite outcome of hospitalization for acute myocardial infarction or stroke, or death, adjusted for baseline demographic characteristics; medications; cholesterol, hemoglobin A1c, and serum creatinine levels; blood pressure; body mass index; health care utilization; and comorbid conditions.

RESULTS

Among 253 690 patients initiating treatment (98 665 with sulfonylurea therapy and 155 025 with metformin therapy), crude rates of the composite outcome were 18.2 per 1000 person-years in sulfonylurea users and 10.4 per 1000 person-years in metformin users (adjusted incidence rate difference, 2.2 [95% CI, 1.4 to 3.0] more CVD events with sulfonylureas per 1000 person-years; adjusted hazard ratio [aHR], 1.21 [CI, 1.13 to 1.30]). Results were consistent for both glyburide (aHR, 1.26 [CI, 1.16 to 1.37]) and glipizide (aHR, 1.15 [CI, 1.06 to 1.26]) in subgroups by CVD history, age, body mass index, and albuminuria; in a propensity score-matched cohort analysis; and in sensitivity analyses.

LIMITATION

Most of the veterans in the study population were white men; data on women and minority groups were limited but reflective of the Veterans Health Administration population.

CONCLUSION

Use of sulfonylureas compared with metformin for initial treatment of diabetes was associated with an increased hazard of CVD events or death.

PRIMARY FUNDING SOURCE

Agency for Healthcare Research and Quality and the U.S. Department of Health and Human Services.

Validating metabolic syndrome through principal component analysis in a medically diverse, realistic cohort

BACKGROUND

The concept of metabolic syndrome has been subject to etiological and clinical controversies in recent years. Associations among the five risk factors (obesity, hypertension, hyperglycemia, high triglyceride levels, and low high-density lipoprotein cholesterol) may help establish the validity of the concept, especially in a cohort representative of an actual population.

METHODS

We used principal component analysis (PCA) to analyze the structure of the physiological components of metabolic syndrome in 7213 patients contained in an administrative database for the Centre Hospitalier Universitaire de Sherbrooke in Sherbrooke, Quebec, a realistic cohort with diverse medical histories. We validated the results by repeating the analysis on stratified and random subgroups of patients, and on different combinations of risk factors. The first axis of the PCA was used to predict coronary heart disease (CHD) and diabetes.

RESULTS

The two first axes explained 53% of the variance. The first axis (33%) was associated in the expected direction with all five predictor variables, consistent with its interpretation as metabolic syndrome. The first axis was more predictive of subsequent CHD and diabetes than the formal definition of metabolic syndrome.

CONCLUSIONS

These results suggest that the concept of metabolic syndrome accurately captures an existing underlying physiological process. A continuous indicator could be constructed to identify metabolic syndrome more accurately, thus improving risk assessment for CHD and diabetes mellitus. Metabolic syndrome can be measured well even without all five predictors. However, discrepancies with other studies suggest that our results may not be generalizable, perhaps because our cohort tends to be sicker.

Applicability of large databases in outcomes research

Outcomes research serves as a mechanism to assess the quality of care, cost effectiveness of treatment, and other aspects of health care. The use of administrative databases in outcomes research is increasing in all medical specialties, including hand surgery. However, the real value of databases can be maximized with a thorough understanding of their contents, advantages, and limitations. We performed a literature review pertaining to databases in medical, surgical, and epidemiologic research, with special emphasis on orthopedic and hand surgery. This article provides an overview of the available database resources for outcomes research, their potential value to hand surgeons, and suggestions to improve their effective use.

Case definitions for acute myocardial infarction in administrative databases and their impact on in-hospital mortality rates

OBJECTIVE

To identify validated ICD-9-CM/ICD-10 coded case definitions for acute myocardial infarction (AMI).

DATA SOURCES

Ovid Medline (1950-2010) was searched to identify studies that validated acute myocardial infarction (AMI) case definitions. Hospital discharge abstract data and chart data were linked to validate identified AMI definitions.

STUDY DESIGN

Systematic literature review, chart review, and administrative data analysis.

DATA COLLECTION/EXTRACTION METHODS

Data on sensitivity/specificity/positive and negative predictive values (PPV and NPV) were extracted from previous studies to identify validated case definitions for AMI. These case definitions were validated in administrative data through chart review and applied to hospital discharge data to assess in-hospital mortality.

PRINCIPAL FINDINGS

Of the eight ICD-9-CM definitions validated in the literature, use of ICD-9-CM code 410 to define AMI had the highest sensitivity (94 percent) and specificity (99 percent). In our data, ICD-9-CM/ICD-10 codes 410/I21-I22 in all available coding fields had high sensitivity (83.3 percent/82.8 percent) and PPV (82.8 percent/82.2 percent). The in-hospital mortality among AMI patients identified using this case definition was 7.6 percent in ICD-9-CM data and 6.6 percent in ICD-10 data.

CONCLUSIONS

We recommend that ICD-9-CM 410 or ICD-10 I21-I22 in the primary diagnosis coding field should be used to define AMI. The use of a consistent validated case definition would improve comparability across studies.

Modified metabolic syndrome criteria for identification of patients at risk of developing diabetes and coronary heart diseases: longitudinal assessment via electronic health records

BACKGROUND

Metabolic syndrome has been shown to predict type 2 diabetes mellitus and cardiovascular events in well-studied cohorts, but lack of appropriate measures in real-life populations has limited its use in clinical settings. We developed and tested an algorithm to identify patients at risk for future diabetes or coronary heart disease (CHD) events using electronic health records (EHRs) at the Centre Hospitalier Universitaire de Sherbrooke (CHUS).

METHODS

Patients older than 18 years who had at least 1 visit (outpatient or inpatient) at the CHUS in 2002 or 2003 were included. We excluded patients with diabetes or CHD at baseline. Patients with at least 3 relevant measurements were classified as no metabolic syndrome (zero criteria met), at-risk for metabolic syndrome (1-2 criteria met), or having metabolic syndrome (≥ 3 criteria met). Incidence of diabetes and CHD were assessed through 2008.

RESULTS

Data from 31,823 patients were included at baseline: 2997 (9.4%) were classified as having metabolic syndrome, while 18,686 (59%) were classified as at risk for metabolic syndrome. During the 5-year follow-up, having metabolic syndrome was associated with a 20.0% risk of developing diabetes (age- and sex-adjusted odds ratio = 5.12 [95% confidence interval, 4.57-5.74]; P < 0.0001) and a 14.7% CHD event incidence (age- and sex-adjusted odds ratio = 1.83 [95% confidence interval, 1.62-2.07]; P < 0.0001).

CONCLUSIONS

An algorithm based on clinically available EHRs could identify patients at high cardiometabolic risk of future diabetes and CHD in the population receiving care at the CHUS.

The impact of high-density lipoprotein cholesterol levels on long-term outcomes after non-ST-elevation myocardial infarction

BACKGROUND

Low serum high-density lipoprotein cholesterol (HDL-C) level is a potent risk factor for developing atherosclerosis, yet it is uncertain if HDL-C level at the time of non-ST-segment elevation myocardial infarction (NSTEMI) has downstream prognostic importance.

METHODS

We evaluated 24,805 patients with NSTEMI aged ≥ 65 years enrolled at 434 Can Rapid Stratification of Unstable Angina Patients Suppress Adverse Outcomes with Early Implementation of the American College of Cardiology/American Heart Association Guidelines (CRUSADE) participating hospitals between February 15, 2003, and December 30, 2006, who had clinical data linked to Medicare files through December 31, 2008. Unadjusted and adjusted hazard ratios (HRs) were calculated to determine the association between HDL-C level at initial hospitalization and all-cause mortality, as well as a combined outcome of all-cause mortality or recurrent myocardial infarction (MI).

RESULTS

Overall, 50% of patients had low HDL-C (≤ 40 mg/dL) and 18% had very low HDL-C (≤ 30 mg/dL). The rate of all-cause mortality was 39.5% during a median follow-up of 2.9 years; death or recurrent MI occurred in 43% in this older population with NSTEMI. Compared with patients who had normal HDL-C, those with very low HDL-C had a modest but significantly higher long-term mortality risk (adjusted HR 1.12, 95% CI 1.06-1.19, P = .0001). The adjusted HR for mortality or recurrent MI was the same. When modeled as a continuous variable, every 5-mg/dL decrement in HDL-C below 40 mg/dL was associated with a 5% increased risk of long-term mortality, as well as the combined end point.

CONCLUSIONS

Older patients with NSTEMI with low levels of HDL-C are at increased risk for downstream mortality or recurrent MI. Future studies are needed to evaluate strategies to reduce this residual risk.

Smoking cigarettes as a coping strategy for chronic pain is associated with greater pain intensity and poorer pain-related function

Smoking cigarettes is prevalent among individuals with chronic pain. Some studies indicate nicotine reduces pain and others suggest it may cause or exacerbate pain. Participants in this cross-sectional study were 151 chronic pain patients from a large, urban VA medical center. Patients were divided into 3 groups: 1) nonsmokers; 2) smokers who deny using cigarettes to cope with pain; and 3) smokers who report using cigarettes to cope with pain. Patients who reported smoking as a coping strategy for chronic pain scored significantly worse compared with the other 2 groups on the majority of measures of pain-related outcome. Nonsmokers and smokers who denied smoking to cope did not differ on any variable examined. After controlling for the effects of demographic and clinical factors, smoking cigarettes as a coping strategy for pain was significantly and positively associated with pain intensity (P = .04), pain interference (P = .005), and fear of pain (P = .04). In addition to assessing general smoking status, a more specific assessment of the chronic pain patient's reasons for smoking may be an important consideration as part of interdisciplinary pain treatment.

PERSPECTIVE

This paper describes the relationship between smoking cigarettes as a mechanism to cope with chronic pain and pain-related outcome. Understanding this relationship may illuminate the broader relationship between smoking and chronic pain and provide new directions for effective interdisciplinary pain treatment.