Clinical validation of the PrecivityAD2 blood test: A mass spectrometry-based test with algorithm combining %p-tau217 and Aβ42/40 ratio to identify presence of brain amyloid

BACKGROUND

With the availability of disease-modifying therapies for Alzheimer's disease (AD), it is important for clinicians to have tests to aid in AD diagnosis, especially when the presence of amyloid pathology is a criterion for receiving treatment.

METHODS

High-throughput, mass spectrometry-based assays were used to measure %p-tau217 and amyloid beta (Aβ)42/40 ratio in blood samples from 583 individuals with suspected AD (53% positron emission tomography [PET] positive by Centiloid > 25). An algorithm (PrecivityAD2 test) was developed using these plasma biomarkers to identify brain amyloidosis by PET.

RESULTS

The area under the receiver operating characteristic curve (AUC-ROC) for %p-tau217 (0.94) was statistically significantly higher than that for p-tau217 concentration (0.91). The AUC-ROC for the PrecivityAD2 test output, the Amyloid Probability Score 2, was 0.94, yielding 88% agreement with amyloid PET. Diagnostic performance of the APS2 was similar by ethnicity, sex, age, and apoE4 status.

DISCUSSION

The PrecivityAD2 blood test showed strong clinical validity, with excellent agreement with brain amyloidosis by PET.

Plasma Aβ42/Aβ40 and phospho-tau217 concentration ratios increase the accuracy of amyloid PET classification in preclinical Alzheimer's disease

INTRODUCTION

Incorporating blood-based Alzheimer's disease biomarkers such as tau and amyloid beta (Aβ) into screening algorithms may improve screening efficiency.

METHODS

Plasma Aβ, phosphorylated tau (p-tau)181, and p-tau217 concentration levels from AHEAD 3-45 study participants were measured using mass spectrometry. Tau concentration ratios for each proteoform were calculated to normalize for inter-individual differences. Receiver operating characteristic (ROC) curve analysis was performed for each biomarker against amyloid positivity, defined by > 20 Centiloids. Mixture of experts analysis assessed the value of including tau concentration ratios into the existing predictive algorithm for amyloid positron emission tomography status.

RESULTS

The area under the receiver operating curve (AUC) was 0.87 for Aβ42/Aβ40, 0.74 for phosphorylated variant p-tau181 ratio (p-tau181/np-tau181), and 0.92 for phosphorylated variant p-tau217 ratio (p-tau217/np-tau217). The Plasma Predicted Centiloid (PPC), a predictive model including p-tau217/np-tau217, Aβ42/Aβ40, age, and apolipoprotein E improved AUC to 0.95.

DISCUSSION

Including plasma p-tau217/np-tau217 along with Aβ42/Aβ40 in predictive algorithms may streamline screening preclinical individuals into anti-amyloid clinical trials.

CLINICALTRIALS

gov Identifier: NCT04468659 HIGHLIGHTS: The addition of plasma phosphorylated variant p-tau217 ratio (p-tau217/np-tau217) significantly improved plasma biomarker algorithms for identifying preclinical amyloid positron emission tomography positivity. Prediction performance at higher NAV Centiloid levels was improved with p-tau217/np-tau217. All models generated for this study are incorporated into the Plasma Predicted Centiloid (PPC) app for public use.

A blood biomarker test for brain amyloid impacts the clinical evaluation of cognitive impairment

OBJECTIVE

The objective of this study was to examine clinicians' patient selection and result interpretation of a clinically validated mass spectrometry test measuring amyloid beta and ApoE blood biomarkers combined with patient age (PrecivityAD® blood test) in symptomatic patients evaluated for Alzheimer's disease (AD) or other causes of cognitive decline.

METHODS

The Quality Improvement and Clinical Utility PrecivityAD Clinician Survey (QUIP I, ClinicalTrials.gov Identifier: NCT05477056) was a prospective, single-arm cohort study among 366 patients evaluated by neurologists and other cognitive specialists. Participants underwent blood biomarker testing and received an amyloid probability score (APS), indicating the likelihood of a positive result on an amyloid positron emission tomography (PET) scan. The primary study outcomes were appropriateness of patient selection as well as result interpretation associated with PrecivityAD blood testing.

RESULTS

A 95% (347/366) concordance rate was noted between clinicians' patient selection and the test's intended use criteria. In the final analysis including these 347 patients (median age 75 years, 56% women), prespecified test result categories incorporated 133 (38%) low APS, 162 (47%) high APS, and 52 (15%) intermediate APS patients. Clinicians' pretest and posttest AD diagnosis probability changed from 58% to 23% in low APS patients and 71% to 89% in high APS patients (p < 0.0001). Anti-AD drug therapy decreased by 46% in low APS patients (p < 0.0001) and increased by 57% in high APS patients (p < 0.0001).

INTERPRETATION

These findings demonstrate the clinical utility of the PrecivityAD blood test in clinical care and may have added relevance as new AD therapies are introduced.

Independent study demonstrates amyloid probability score accurately indicates amyloid pathology

BACKGROUND

The amyloid probability score (APS) is the model read-out of the analytically validated mass spectrometry-based PrecivityAD^® blood test that incorporates the plasma Aβ42/40 ratio, ApoE proteotype, and age to identify the likelihood of brain amyloid plaques among cognitively impaired individuals being evaluated for Alzheimer's disease.

PURPOSE

This study aimed to provide additional independent evidence that the pre-established APS algorithm, along with its cutoff values, discriminates between amyloid positive and negative individuals.

METHODS

The diagnostic performance of the PrecivityAD test was analyzed in a cohort of 200 nonrandomly selected Australian Imaging, Biomarker & Lifestyle Flagship Study of Aging (AIBL) study participants, who were either cognitively impaired or healthy controls, and for whom a blood sample and amyloid PET imaging were available.

RESULTS

In a subset of the dataset aligned with the Intended Use population (patients aged 60 and older with CDR ≥0.5), the pre-established APS algorithm predicted amyloid PET with a sensitivity of 84.9% (CI: 72.9-92.1%) and specificity of 96% (CI: 80.5-99.3%), exclusive of 13 individuals for whom the test was inconclusive.

INTERPRETATION

The study shows individuals with a high APS are more likely than those with a low APS to have abnormal amounts of amyloid plaques and be on an amyloid accumulation trajectory, a dynamic and evolving process characteristic of progressive AD pathology. Exploratory data suggest APS retains its diagnostic performance in healthy individuals, supporting further screening studies in the cognitively unimpaired.

Can We Use Blood Biomarkers as Entry Criteria and for Monitoring Drug Treatment Effects in Clinical Trials? A Report from the EU/US CTAD Task Force

In randomized clinical trials (RCTs) for Alzheimer's Disease (AD), cerebrospinal fluid (CSF) and positron emission tomography (PET) biomarkers are currently used for the detection and monitoring of AD pathological features. The use of less resource-intensive plasma biomarkers could decrease the burden to study volunteers and limit costs and time for study enrollment. Blood-based markers (BBMs) could thus play an important role in improving the design and the conduct of RCTs on AD. It remains to be determined if the data available on BBMs are strong enough to replace CSF and PET biomarkers as entry criteria and monitoring tools in RCTs.

Assessment of a Plasma Amyloid Probability Score to Estimate Amyloid Positron Emission Tomography Findings Among Adults With Cognitive Impairment

IMPORTANCE

The diagnostic evaluation for Alzheimer disease may be improved by a blood-based diagnostic test identifying presence of brain amyloid plaque pathology.

OBJECTIVE

To determine the clinical performance associated with a diagnostic algorithm incorporating plasma amyloid-β (Aβ) 42:40 ratio, patient age, and apoE proteotype to identify brain amyloid status.

DESIGN, SETTING, AND PARTICIPANTS

This cohort study includes analysis from 2 independent cross-sectional cohort studies: the discovery cohort of the Plasma Test for Amyloidosis Risk Screening (PARIS) study, a prospective add-on to the Imaging Dementia-Evidence for Amyloid Scanning study, including 249 patients from 2018 to 2019, and MissionAD, a dataset of 437 biobanked patient samples obtained at screenings during 2016 to 2019. Data were analyzed from May to November 2020.

EXPOSURES

Amyloid detected in blood and by positron emission tomography (PET) imaging.

MAIN OUTCOMES AND MEASURES

The main outcome was the diagnostic performance of plasma Aβ42:40 ratio, together with apoE proteotype and age, for identifying amyloid PET status, assessed by accuracy, sensitivity, specificity, and area under the receiver operating characteristic curve (AUC).

RESULTS

All 686 participants (mean [SD] age 73.2 [6.3] years; 368 [53.6%] men; 378 participants [55.1%] with amyloid PET findings) had symptoms of mild cognitive impairment or mild dementia. The AUC of plasma Aβ42:40 ratio for PARIS was 0.79 (95% CI, 0.73-0.85) and 0.86 (95% CI, 0.82-0.89) for MissionAD. Ratio cutoffs for Aβ42:40 based on the Youden index were similar between cohorts (PARIS: 0.089; MissionAD: 0.092). A logistic regression model (LRM) incorporating Aβ42:40 ratio, apoE proteotype, and age improved diagnostic performance within each cohort (PARIS: AUC, 0.86 [95% CI, 0.81-0.91]; MissionAD: AUC, 0.89 [95% CI, 0.86-0.92]), and overall accuracy was 78% (95% CI, 72%-83%) for PARIS and 83% (95% CI, 79%-86%) for MissionAD. The model developed on the prospectively collected samples from PARIS performed well on the MissionAD samples (AUC, 0.88 [95% CI, 0.84-0.91]; accuracy, 78% [95% CI, 74%-82%]). Training the LRM on combined cohorts yielded an AUC of 0.88 (95% CI, 0.85-0.91) and accuracy of 81% (95% CI, 78%-84%). The output of this LRM is the Amyloid Probability Score (APS). For clinical use, 2 APS cutoff values were established yielding 3 categories, with low, intermediate, and high likelihood of brain amyloid plaque pathology.

CONCLUSIONS AND RELEVANCE

These findings suggest that this blood biomarker test could allow for distinguishing individuals with brain amyloid-positive PET findings from individuals with amyloid-negative PET findings and serve as an aid for Alzheimer disease diagnosis.

Blood Biomarkers from Research Use to Clinical Practice: What Must Be Done? A Report from the EU/US CTAD Task Force

Timely and accurate diagnosis of Alzheimer's disease (AD) in clinical practice remains challenging. PET and CSF biomarkers are the most widely used biomarkers to aid diagnosis in clinical research but present limitations for clinical practice (i.e., cost, accessibility). Emerging blood-based markers have the potential to be accurate, cost-effective, and easily accessible for widespread clinical use, and could facilitate timely diagnosis. The EU/US CTAD Task Force met in May 2022 in a virtual meeting to discuss pathways to implementation of blood-based markers in clinical practice. Specifically, the CTAD Task Force assessed: the state-of-art for blood-based markers, the current use of blood-based markers in clinical trials, the potential use of blood-based markers in clinical practice, the current challenges with blood-based markers, and the next steps needed for broader adoption in clinical practice.

The PrecivityAD™ test: Accurate and reliable LC-MS/MS assays for quantifying plasma amyloid beta 40 and 42 and apolipoprotein E proteotype for the assessment of brain amyloidosis

BACKGROUND

There is an unmet need for an accessible, less invasive, cost-effective method to facilitate clinical trial enrollment and aid in clinical Alzheimer's disease (AD) diagnosis. APOE genotype affects the clearance and deposition of amyloid-beta (Aβ) with APOE4 carriers having increased risk while APOE2 alleles appear to be protective. Lower plasma Aβ42/40 correlates with brain amyloidosis. In response, C₂N has developed the PrecivityAD™ test; plasma LC-MS/MS assays for Aβ isoform quantitation and qualitative APOE isoform-specific proteotyping.

METHODS

In accord with CLIA standards, we developed and validated assay performance: precision, accuracy, linearity, limit of detection (LoD), interferences.

RESULTS

Within-day precision varied from 1.5-3.0% (Aβ40) and 2.5-8.4% (Aβ42). Total (within-lab) variability was 2.7-7.7% (Aβ40) and 3.1-9.5% (Aβ42). Aβ40 quantitation was linear from 10 to 1780 pg/mL; Aβ42 was linear from 2 to 254 pg/mL. LoD was 11 and 2 pg/mL for Aβ40 and Aβ42, respectively. APOE proteotypes were 100% concordant with genotype, while LoD (fM) was much lower than APOE concentrations observed in plasma (mM).

CONCLUSIONS

The PrecivityAD™ assays are precise, accurate, sensitive, and linear over a wide analytical range, free from significant interferences, and suitable for use in the clinical laboratory.

A blood-based diagnostic test incorporating plasma Aβ42/40 ratio, ApoE proteotype, and age accurately identifies brain amyloid status: findings from a multi cohort validity analysis

BACKGROUND

The development of blood-based biomarker tests that are accurate and robust for Alzheimer's disease (AD) pathology have the potential to aid clinical diagnosis and facilitate enrollment in AD drug trials. We developed a high-resolution mass spectrometry (MS)-based test that quantifies plasma Aβ42 and Aβ40 concentrations and identifies the ApoE proteotype. We evaluated robustness, clinical performance, and commercial viability of this MS biomarker assay for distinguishing brain amyloid status.

METHODS

We used the novel MS assay to analyze 414 plasma samples that were collected, processed, and stored using site-specific protocols, from six independent US cohorts. We used receiver operating characteristic curve (ROC) analyses to assess assay performance and accuracy for predicting amyloid status (positive, negative, and standard uptake value ratio; SUVR). After plasma analysis, sites shared brain amyloid status, defined using diverse, site-specific methods and cutoff values; amyloid PET imaging using various tracers or CSF Aβ42/40 ratio.

RESULTS

Plasma Aβ42/40 ratio was significantly (p < 0.001) lower in the amyloid positive vs. negative participants in each cohort. The area under the ROC curve (AUC-ROC) was 0.81 (95% CI = 0.77-0.85) and the percent agreement between plasma Aβ42/40 and amyloid positivity was 75% at the optimal (Youden index) cutoff value. The AUC-ROC (0.86; 95% CI = 0.82-0.90) and accuracy (81%) for the plasma Aβ42/40 ratio improved after controlling for cohort heterogeneity. The AUC-ROC (0.90; 95% CI = 0.87-0.93) and accuracy (86%) improved further when Aβ42/40, ApoE4 copy number and participant age were included in the model.

CONCLUSIONS

This mass spectrometry-based plasma biomarker test: has strong diagnostic performance; can accurately distinguish brain amyloid positive from amyloid negative individuals; may aid in the diagnostic evaluation process for Alzheimer's disease; and may enhance the efficiency of enrolling participants into Alzheimer's disease drug trials.

Preclinical and Clinical Development of ABBV-8E12, a Humanized Anti-Tau Antibody, for Treatment of Alzheimer's Disease and Other Tauopathies

Tau neurofibrillary tangles are found in the brains of patients suffering from Alzheimer's disease and other tauopathies. The progressive spreading of tau pathology from one brain region to the next is believed to be caused by extracellular transsynaptic transmission of misfolded tau between neurons. Preclinical studies have shown that antibodies against tau can prevent this transfer of misfolded tau between cells. Thus, antibodies against tau have the potential to stop or slow the progression of tau pathology observed in human tauopathies. To test this hypothesis, a humanized anti-tau antibody (ABBV-8E12) was developed and a phase 1 clinical trial of this antibody has been completed. The double-blind, placebo-controlled phase 1 study tested single doses of ABBV-8E12 ranging from 2.5 to 50 mg/kg in 30 patients with progressive supranuclear palsy (PSP). ABBV-8E12 was found to have an acceptable safety profile with no clinically concerning trends in the number or severity of adverse events between the placebo and dosed groups. Pharmacokinetic modelling showed that the antibody has a plasma half-life and cerebrospinal fluid:plasma ratio consistent with other humanized antibodies, and there were no signs of immunogenicity against ABBV-8E12. Based on the acceptable safety and tolerability profile of single doses of ABBV-8E12, AbbVie is currently enrolling patients into two phase 2 clinical trials to assess efficacy and safety of multiple doses of ABBV-8E12 in patients with early Alzheimer's disease or PSP.

Regulatory review of novel therapeutics--comparison of three regulatory agencies

BACKGROUND

The upcoming reauthorization of the Prescription Drug User Fee Act focuses on improving the review process for new drug applications at the Food and Drug Administration (FDA).

METHODS

Using publicly available information from the FDA, the European Medicines Agency (EMA), and Health Canada, we compared the time for completion of the first review and the total review time for all applications involving novel therapeutic agents approved by the three regulatory agencies from 2001 through 2010 and determined the geographic area in which each novel therapeutic agent was first approved for use.

RESULTS

There were 510 applications for novel therapeutic agents approved from 2001 through 2010--225 by the FDA, 186 by the EMA, and 99 by Health Canada; among the applications, there were 289 unique agents. The median length of time for completion of the first review was 303 days (interquartile range, 185 to 372) for applications approved by the FDA, 366 days (interquartile range, 310 to 445) for those approved by the EMA, and 352 days (interquartile range, 255 to 420) for those approved by Health Canada (P<0.001 for the comparison across the three agencies). The median total review time was also shorter at the FDA than at the EMA or Health Canada (P=0.002). Among the 289 unique novel therapeutic agents, 190 were approved in both the United States and Europe (either by the EMA or through the mutual recognition process), of which 121 (63.7%) were first approved in the United States; similarly, 154 were approved in both the United States and Canada, of which 132 (85.7%) were first approved in the United States.

CONCLUSIONS

For novel therapeutic agents approved between 2001 and 2010, the FDA reviewed applications involving novel therapeutics more quickly, on average, than did the EMA or Health Canada, and the vast majority of these new therapeutic agents were first approved for use in the United States. (Funded by the Pew Charitable Trusts.).

Race, medical researcher distrust, perceived harm, and willingness to participate in cardiovascular prevention trials

Minority underrepresentation exists in medical research including cardiovascular clinical trials, but the hypothesis that this relates to distrust in medical researchers is unproven. Therefore, we examined whether African American persons differ from white persons in perceptions of the risks/benefits of trial participation and distrust toward medical researchers, and whether these factors influence willingness to participate (WTP) in a clinical drug trial. Participants were self-administered a survey regarding WTP in a cardiovascular drug trial given to 1440 randomly selected patients from 13 Maryland outpatient cardiology and general medicine clinics. Patients reported their WTP, rated their perceived chances of experiencing health benefit and harm, and rated their distrust toward researchers. Of eligible participants, 70% responded, and 717 individuals were included: 36% African American and 64% white. African American participants possessed lower WTP than white participants (27% vs. 39%, p = 0.001) and had higher mean distrust scores than whites (p < 0.0001). African American participants more frequently reported that doctors would less fully explain research participation to them (24% vs. 13%, p < 0.001), use them as guinea pigs without their consent (72% vs. 49%, p < 0.001), prescribe medication as a way of experimenting on people without their knowledge (35% vs. 16%, p < 0.001), and ask them to participate in research even if it could harm them (24% vs. 15%, p = 0.002). African American participants also more often believed they could less freely ask their doctor questions (8% vs. 2%, p < 0.001) and that doctors had previously experimented on them without their consent (58% vs. 25%, p < 0.001). African American participants expressed lesser WTP than white participants after controlling for racial differences in age, sex, socioeconomic status and cardiovascular disease risk profiles (multivariable odds ratio [OR], 0.57; 95% confidence interval [CI], 0.39-0.85). The impact of race was attenuated and nonsignificant after adjustment for potential mediating factors of racial differences in medical researcher distrust and perceived risk of harm (explanatory model OR, 0.84; 95% CI 0.54-1.30). In summary, African American participants expressed markedly greater concerns about experiencing harm from participation in clinical trials and distrust toward medical researchers than white participants. These factors, in turn, appear to explain much of the resistance among African American persons to participate in clinical trials compared to white persons.

Sex Differences in Perceived Risks, Distrust, and Willingness to Participate in Clinical Trials

BACKGROUND

Multiple sex differences exist in cardiovascular disease burden and treatment efficacies; adequate participation of both sexes is crucial to clinical research.

METHODS

A multicenter, double-blind, randomized study evaluated sex and trial scenarios on willingness to participate (WTP) in cardiovascular prevention trials and examined sex differences in perceived risks and distrust. Hypothetical trial scenarios randomized multifactorial vignettes of adverse effects, trial durations, sponsors, financial incentives, and conflicts of interest.

RESULTS

With 783 participants across 13 clinical centers, women showed lower distrust of medical researchers, perceived greater risk of myocardial infarction, and perceived greater risk of harm from trial participation than men. Men had 15% greater WTP than women (33.1% vs 28.7%; relative risk [RR], 1.15; 95% confidence interval [CI], 1.02-1.31); adjusting for explanatory mediators, we found that sex differences in perceived risks and benefits explained the sex gap in WTP. Although greater perceived probability of harm (RR, 0.41; 95% CI, 0.23-0.72), health benefit (RR, 2.99; 95% CI, 1.63-5.46), and quality of care (RR, 1.71; 95% CI, 1.12-2.61) strongly predicted WTP (for perceived probabilities >or=80% vs <20%) similarly in both sexes, and perceptions of distrust and myocardial infarction risk predicted WTP differently between sexes (P<or=.01 for interactions), age, history of coronary artery disease, hypertension, and diabetes mellitus increased WTP in men but not in women (P<or=.05 for sex interactions). Compared with no financial conflict, disclosure of investigator patent ownership increased WTP in women, while it decreased WTP in men (P=.02 for sex interaction). Monetary incentives were overall more effective on WTP in women (P=.03 for sex interaction).

CONCLUSIONS

In this multicenter study, women perceived greater risk of harm and myocardial infarction and showed lower WTP in cardiovascular prevention trials. Evidence underscores the importance of sex in influencing clinical trial enrollment.

Treatment of Staphylococcus aureus biofilm infection by the quorum-sensing inhibitor RIP

The quorum-sensing inhibitor RIP inhibits staphylococcal TRAP/agr systems and both TRAP- and agr-negative strains are deficient in biofilm formation in vivo, indicating the importance of quorum sensing to biofilms in the host. RIP injected systemically into rats has been found to have strong activity in preventing methicillin-resistant Staphylococcus aureus graft infections, suggesting that RIP can be used as a therapeutic agent.

The Association of Subclinical Coronary Atherosclerosis With Abdominal and Total Obesity in Asymptomatic Men

The present study assesses and compares the association of waist circumference and body mass index with presence and severity of coronary artery calcium in asymptomatic men. The study population consisted of 451 asymptomatic men free of known coronary heart disease. The subjects were broadly divided into tertiles by waist circumference (< or =92 cm; 92.5-100 cm; > or =101 cm) and body mass index (< or =25.5 kg/m2; 25.6-28.4 kg/m2; > or =28.5 kg/m2), respectively. The risk of coronary artery calcium was two-fold higher among those with a waist circumference in the highest tertile (> or =101 cm) compared with men with waist circumference < or =92 cm. The relationship was found to be independent of body mass index, age, and conventional coronary heart disease risk factors. No significant association of body mass index with coronary artery calcium was observed. Our results are consistent with evidence that measures of central obesity, compared with body mass index, are more strongly related to clinical as well as subclinical coronary heart disease end points.

Reducing global risk for cardiovascular disease: using lifestyle changes and pharmacotherapy

Cardiovascular disease (CVD) is the leading cause of death and disability in industrialized societies, due in large part to the lack of a comprehensive approach to control the risk factors for atherosclerosis. One strategy for reducing an individual's global CVD risk relies on a targeted approach that modifies each of the major independent risk factors prevalent in both symptomatic (secondary prevention) and asymptomatic (primary prevention) patients. These interventions include lipid lowering, smoking cessation, blood pressure control, glycemic control, regular exercise, and the use of various medications. This review offers an evidence-based strategy toward reducing an individual's global risk for CVD by addressing the modifiable, major independent risk factors.

Framingham risk equation underestimates subclinical atherosclerosis risk in asymptomatic women

BACKGROUND

Coronary heart disease (CHD) is the leading cause of death among American women. Currently, global risk assessment derived by Framingham risk equation (FRE) is used to identify women at increased risk for CHD. Electron-beam computed tomography (EBCT) derived coronary artery calcium (CAC) scores are validated markers for future CHD events among asymptomatic individuals. However, the adequacy of FRE for identifying asymptomatic women with CAC is unknown.

METHODS AND RESULTS

We studied 2447 consecutive non-diabetic asymptomatic females (55 +/- 10 years). Based upon FRE, 90% were classified as low-risk (FRE < or = 9% 10-year risk of hard CHD events), 10% intermediate-risk (10-20%), and none were considered as high-risk (> 20%). Coronary artery calcium was present in 33%, whereas CAC > or = 100 and CAC > or = 400 were seen in 10 and 3% of women, respectively. Overall, 20% of women had age-gender derived > or = 75th percentile CAC. According to FRE, the majority (84%) of women with significant CAC > or = 75th percentile were classified as low-risk. Approximately half (45%) of low-risk women with > or = 2 CHD risk factors and a family history of premature CHD had significant CAC.

CONCLUSION

Framingham risk equation frequently classifies women as being low-risk, even in the presence of significant CAC. Determination of CAC may provide incremental value to FRE in identifying asymptomatic women who will benefit from targeted preventative measures.

The influence of health status, age, and race on screening mammography in elderly women

BACKGROUND

Screening mammography is controversial for elderly women because of an absence of efficacy data. Decisions to screen are based on individualized assessment of risks and benefits. Our objective was to determine how screening mammography varies by age and race when adjusted for propensity to die.

METHODS

In a retrospective cohort study, rates of screening mammogram performed in 2000-2001 based on claims, adjusted for propensity to die in 2000, were determined for a nationally representative 5% random sample of female fee-for-service Medicare beneficiaries 65 years and older in (N = 722,310).

RESULTS

The overall rate of screening was 39%. When stratified into quintiles by propensity to die, 2-year rates ranged from 61% in the lowest-risk group to 5% in the highest-risk group. In analyses stratified by age and adjusted for propensity to die, 42% of women aged 65 to 69 years were screened, declining to 26% of women 85 years and older (P<.001). Adjusted screening rates for white women, black women, and women of other races were 40%, 30%, and 25%, respectively (P<.001). Thus, among women with similar health status, the youngest women were 1.61 times more likely to be screened compared with the oldest; compared with black women and women of other races, white women were 1.38 and 1.60 times, respectively, more likely to be screened.

CONCLUSIONS

Decisions to screen for breast cancer are related not only to health status but also to age and race. Underuse and overuse of screening mammography likely occurs owing to age- and race-associated decision making. Assessment of life expectancy may more accurately identify women who could benefit from screening.

Difference in atherosclerosis burden in different nations and continents assessed by coronary artery calcium

We utilized coronary artery calcium scores (CACS) to assess differences in atherosclerosis burden between asymptomatic White populations living in continents with different cardiovascular disease rates. The similarities in the genetic pool between Brazilian and Portuguese Caucasian subjects offered an opportunity to assess the influence of environmental factors on the development of atherosclerosis. We reviewed CACS data from 17,563 individuals (12,378 men and 5169 women) collected in the USA (74% of the subjects), Brazil (15% of the subjects) and Portugal (11% of the subjects). CACS was absent in 80 and 88% of Portuguese men and women, compared with 46 and 62% and 33 and 59% of Brazilian and US counterparts (p<0.0001). Although the US subjects showed the lowest prevalence of risk factors they had a higher median (interquartile range) CACS than the Brazilian and the Portuguese cohorts: 4 (0;87), 1 (0;68) and 0 (0;0), respectively (p<0.0001). After adjusting for differences in age and cardiovascular risk factors, US men showed higher relative risk ratios of having any CACS than either Brazilian or Portuguese men. Brazilian and US women did not differ as far as risk of CACS although they demonstrated a greater risk than Portuguese women. In this study, significant differences in CACS were detected among three nations in different continents. The CACS differences paralleled the respective cardiovascular mortality rates.

Relation of family history of premature coronary heart disease and metabolic risk factors to risk of coronary arterial calcium in asymptomatic subjects

We studied 6,141 consecutive, asymptomatic, nondiabetic patients who underwent electron beam tomography and explored the interaction between metabolic risk factors (RFs) and premature family history (FH) of coronary heart disease (CHD) in predicting the presence and severity of coronary arterial calcium (CAC). In the presence of >2 metabolic RFs, patients with a positive FH of premature CHD had a significantly higher prevalence of any CAC, CAC >/=100, and CAC >/=75th age-gender percentile than those without a FH of CHD. Our study demonstrated that a familial propensity to subclinical atherosclerosis interacts with the presence of >/=2 metabolic RFs, magnifying the risks for those exposed to both.

Underlying risk factors incrementally add to the standard risk estimate in detecting subclinical atherosclerosis in low- and intermediate-risk middle-aged asymptomatic individuals

BACKGROUND

Traditional risk factors predict the 10-year risk of developing coronary heart disease (CHD). Underlying risk factors like physical inactivity, obesity (BMI >30 kg/m2), and family history of premature CHD are independently associated with CHD. High burden of coronary artery calcification (CAC) on electron beam tomography (EBT) is a CHD risk equivalent.

GOALS

To determine the association between CAC and traditional risk assessment and whether the presence of added underlying risk factors is associated with advanced CAC in low- and intermediate-risk individuals.

METHODS

After excluding patients with CHD, we studied 8549 asymptomatic individuals referred for EBT for cardiac risk assessment. Traditional myocardial infarction risk score was estimated according to Framingham criteria, and individuals were divided into 3 groups: low-risk (< or =9% MI risk over the next 10 years), intermediate-risk (10%-20% risk), and high-risk (>20 % risk). Advanced CAC was defined as a calcium score > or =75th percentile based on sex and age.

RESULTS

The prevalence of advanced CAC was 20% in low-risk, 27% in intermediate-risk, and 31% in high-risk individuals (P < .001). Underlying risk factors were incrementally associated with advanced CAC in low- and intermediate-risk individuals (P < .001). A receiver operating characteristic curve analysis revealed that addition of underlying risk factors to traditional risk assessment increased the area under the curve significantly from 0.56 to 0.62 (P < .001).

CONCLUSION

A substantial proportion of low- and intermediate-risk individuals have advanced CAC. Adding family history, obesity, and physical inactivity to traditional risk assessment improves prediction of advanced CAC, which may lead these individuals to be treated more aggressively at an earlier age.

Prospective evaluation of the relationship between platelet-leukocyte conjugate formation and recurrent myocardial ischemia in patients with acute coronary syndromes

Platelet-leukocyte conjugates are increased in patients with coronary artery disease but the relationship between conjugate formation and myocardial ischemic outcome is unknown. We prospectively evaluated the relationship between conjugate formation and the development of recurrent myocardial ischemia in patients with acute coronary syndromes (ACS). Platelet-leukocyte conjugate formation (induced by thrombin receptor activating peptide (TRAP)) and platelet aggregation (induced by ADP and arachidonic acid) were assessed in 30 patients with unstable angina or non-ST elevation myocardial infarction. All patients were treated with beta-blockers, aspirin, heparin, and GPIIb-IIIa antagonists and were followed for in-hospital recurrent myocardial ischemia. Troponin I and C-reactive protein (CRP) were also measured. Seven patients (23%) experienced recurrent ischemia. Platelet-neutrophil conjugates were greater in ischemic patients (59 +/- 9 and 36 +/- 4%, P = 0.007, for + ischemia and -ischemia, respectively). Platelet aggregation did not differ between ischemic and nonischemic patients, and there was no significant relationship between aspirin resistance and ischemic outcome. Troponin I was greater in patients who developed recurrent ischemia (3.04 +/- 1.73 vs. 0.70 +/- 0.21 ng/ml, P = 0.03, for +ischemia and -ischemia, respectively) but CRP was not. TRAP-induced platelet-neutrophil conjugate formation was an independent predictor of ischemic outcome (OR 1.07, 95% CI 1.00-1.15, for each 1% increase in conjugate formation). Receiver operator characteristic analysis showed platelet-neutrophil conjugates to have good ability to discriminate between ischemic and nonischemic patients (AUC of 0.84, P < 0.05). TRAP induced platelet-neutrophil conjugate formation is related to in vivo ischemic risk in ACS patients.

Coronary Artery Calcification and Family History of Premature Coronary Heart Disease

Background— The objective of the study was to assess the association of a family history (FH) of premature coronary heart disease (CHD) with coronary artery calcification (CAC) in asymptomatic individuals and to compare the effects of sibling or parental FH on the risk of subclinical atherosclerosis.

Methods and Results— CAC by electron beam tomography was performed in 8549 asymptomatic individuals (69% men; mean age, 52±9 years). The prevalence and odds of any CAC and extent of CAC stratified according to FH of premature CHD were determined. Those with (1) no FH of CHD, (2) FH of premature CHD in parents, or (3) FH in siblings had a prevalence of CAC of 55%, 64%, and 78% ( P <0.0001) among men and 27%, 36%, and 56% ( P <0.0001) among women, respectively. The multivariate regression analysis demonstrated that the odds ratio (95% confidence interval) for the presence of CAC was 1.3 (1.1 to 1.6) among those with positive FH of premature CHD in parents only, 2.3 (1.7 to 3.1) and 2.5 (1.8 to 3.3) among those in siblings and a combined FH compared with those without FH of CHD in men, respectively. Among women, the corresponding odds ratios were 1.3 (1.0 to 1.8), 2.3 (1.7 to 3.6), and 1.9 (1.3 to 3.1), respectively. A similar trend was observed in the association of FH of premature CHD with increasing CAC scores.

Conclusions— Our study demonstrates a highly significant association between FH of premature CHD and the presence and extent of CAC. Furthermore, within the limits of self-reporting of family history, our findings suggest that a sibling history is more strongly associated with subclinical coronary atherosclerosis than a parental history of premature CHD.

Relation of degree of physical activity to coronary artery calcium score in asymptomatic individuals with multiple metabolic risk factors

Lack of physical activity (PA) increases risk of coronary heart disease. Metabolic risk factors increase the risk of coronary heart disease and development of advanced coronary artery calcium (CAC). We hypothesized that, in a population with multiple metabolic risk factors (> or =2), the degree of PA would be inversely associated with the degree and prevalence of CAC. After excluding subjects who had known diabetes and coronary heart disease, we studied 779 asymptomatic patients referred for electron beam tomography. All patients had > or =2 of the following metabolic risk factors: blood pressure > 130/85 mm Hg, serum triglycerides >150 mg/dl, serum high-density lipoprotein < 40 and < 50 mg/dl in men and women, respectively, and body mass index >30 kg/m(2). Advanced CAC was defined as a calcium score >75th percentile based on gender and age. In the study, 37% patients were sedentary, 26% engaged in moderate-duration (< 30 minutes 1 to 2 times/week) PA, and 37% engaged in long-duration (> or =30 minutes > or =3 times/week) PA. The median CAC scores were 24 (sedentary), 18 (moderate PA), and 11 (long-duration PA; p <0.002). Advanced CAC was prevalent in 26% of sedentary patients, 24% of patients who performed moderate PA, and 16% of patients who engaged in long-duration PA (p <0.05). On logistic regression analysis, long-duration PA had an independent inverse association with advanced CAC. Thus, asymptomatic patients who have > or =2 metabolic risk factors and who regularly engage in long-duration PA have a lower prevalence of CAC than do those who are sedentary or participate in moderate-duration PA.

A Practical and Evidence-Based Approach to Cardiovascular Disease Risk Reduction

Implementation of the numerous lifestyle and medical management options for secondary prevention of cardiovascular disease remains a daunting goal for primary care physicians and cardiologists alike. Despite the existence of expert consensus guidelines on cardiovascular prevention by the American College of Cardiology and the American Heart Association, therapies known to improve patient care and decrease morbidity and mortality remain underutilized. This review attempts to simplify cardiovascular risk reduction by summarizing key clinical trials in an "ABC" format. We believe that if health care providers and patients use such a format, important lifestyle and pharmacologic options will more likely be addressed.

Coronary artery calcium volume scores on electron beam tomography in 12,936 asymptomatic adults

We developed age- and gender-specific normative tables of calcium volume scores by using data from 12,936 asymptomatic patients who underwent electron beam tomographic scanning and compared the volume with the Agatston scores obtained in the same subjects. The 2 scores increased as the number of atherosclerotic risk factors increased. The volume scores were statistically smaller than the Agatston scores at the upper quartile level.

Evolving targets for risk reduction in diabetes

Recent evidence shows that target low-density lipoprotein cholesterol should be less than 100 mg/dl in patients with diabetes, and that even those with initially low levels benefit from pharmacologic therapy. Recent studies document that blood pressures lower than the previous target of 140/90 mmHg are beneficial, in addition to providing observational evidence against a lower threshold of benefit. Evidence that addresses the effect of blood glucose on macrovascular disease risk in patients with diabetes is reviewed. Finally, recommendations are made regarding systematic changes in healthcare delivery that will facilitate risk reduction strategies in diabetes.

Economics of reducing menstruation with trimonthly-cycle oral contraceptive therapy: comparison with standard-cycle regimens

OBJECTIVE

To evaluate whether, and under what circumstances, trimonthly-cycle oral contraceptive pill (OCP) therapy is cost saving over standard-cycle OCP therapy for reducing the severity of menstrual-related symptoms.

METHODS

We created three economic models, with each model representing a unique cost perspective (societal, private third party, and patient), to estimate the incremental annual costs associated with women taking trimonthly-cycle rather than standard-cycle OCP. Direct costs considered were costs for OCP prescriptions, female hygiene products, generic over-the-counter pain relievers and iron tablets, home pregnancy tests, and physician visits for menstrual-related concerns. Indirect costs considered were lost wages due to menstruation-related disability and opportunity costs of physician visits. We derived base-case and sensitivity range estimates from prior literature, public use data, expert opinion, and cross-sectional survey data that we collected from 59 adult women taking standard-cycle OCP visiting a large, community-based gynecology office. All costs were adjusted to 2002 US dollars.

RESULTS

Under base-case assumptions that both regimens were equivalently priced (1.16 US dollars/pill) and trimonthly OCP reduces hygiene product use by 50%, annual societal costs per person were 460 US dollars for trimonthly OCP and 501 US dollars for standard OCP (incremental cost savings = 41 US dollars). Assuming no difference in monthly drug copayment costs between the two regimens (5.00 US dollars), annual private third-party costs were nearly identical at 365 US dollars per regimen. Annual patient costs were 95 US dollars for trimonthly OCP and 136 US dollars for standard OCP. Trimonthly OCP remained cost saving to society as long its price remained below a 9% premium to standard OCP prices. The degree to which trimonthly OCP reduces hygiene product use also significantly influenced the cost difference between the two regimens.

CONCLUSION

Compared with standard-cycle OCP, trimonthly-cycle OCP appears to be associated with significant societal and patient cost savings. These savings are highly conditional upon trimonthly OCP being priced similarly to standard OCP.

Noncardiac comorbidity increases preventable hospitalizations and mortality among Medicare beneficiaries with chronic heart failure

OBJECTIVES

We studied the impact of noncardiac comorbidity on potentially preventable hospitalizations and mortality in elderly patients with chronic heart failure (CHF).

BACKGROUND

Chronic HF disproportionately affects older individuals, who typically have extensive comorbidity. However, little is known about how noncardiac comorbidity complicates care in these patients.

METHODS

This was a cross-sectional study of 122,630 individuals age >/=65 years with CHF identified through a 5% random sample of all U.S. Medicare beneficiaries. We assessed the relationship of the 20 most common noncardiac comorbidities to one-year potentially preventable hospitalizations and total mortality. Preventable hospitalizations were determined by admissions for ambulatory care sensitive conditions using predefined criteria.

RESULTS

Sixty-five percent of the sample had at least one hospitalization, of which 50% were potentially preventable. Exacerbations of CHF accounted for 55% of potentially preventable hospitalizations. Nearly 40% of patients with CHF had >/=5 noncardiac comorbidities, and this group accounted for 81% of the total inpatient hospital days experienced by all CHF patients. The risk of hospitalization and potentially preventable hospitalization strongly increased with the number of chronic conditions (both p < 0.0001). After controlling for demographic factors and other diagnoses, comorbidities that were associated consistently with notably higher risks for CHF-preventable and all-cause preventable hospitalizations, and mortality, included chronic obstructive pulmonary disease/bronchiectasis, renal failure, diabetes, depression, and other lower respiratory diseases (all p < 0.01).

CONCLUSIONS

Noncardiac comorbidities are highly prevalent in older patients with CHF and strongly associate with adverse clinical outcomes. Cardiologists and other providers routinely caring for older patients with CHF may improve outcomes in this high-risk population by better recognizing non-CHF conditions, which may complicate traditional CHF management strategies.

Preventable hospitalization among elderly Medicare beneficiaries with type 2 diabetes

OBJECTIVE

To examine the impact of comorbid conditions on preventable hospitalizations among Medicare beneficiaries aged > or =65 years with type 2 diabetes.

RESEARCH DESIGN AND METHODS

Data were drawn from the 1999 Medicare Standard Analytic Files, a 5% nationally representative random sample of Medicare beneficiaries. The analysis sample included 193,556 Medicare beneficiaries aged > or =65 years with type 2 diabetes (ICD-9-CM codes 250.xx) who were enrolled in fee-for-service Medicare. Preventable hospitalization was assessed by measuring ambulatory care-sensitive conditions, an accepted measure of hospitalizations that could have been prevented with appropriate outpatient care. Multivariable analyses controlled for demographics; mortality; renal, ophthalmic, or neurological manifestations of diabetes; type of physician providing the outpatient care; and per capita community-level indicators of income and hospital beds.

RESULTS

Ninety-six percent of beneficiaries in the sample had a comorbidity, and 46% had five or more comorbidities. Among beneficiaries with type 2 diabetes, cardiovascular-related comorbidities were common and accounted for increased odds of preventable hospitalization, controlling for other factors. The likelihood of a preventable hospitalization increased in the presence of a claim for comorbid congestive heart failure, cardiomyopathy, coronary atherosclerosis, hypertension, or cardiac dysrythmias. Noncardiovascular comorbidities associated with a greater likelihood of preventable hospitalization included chronic obstructive pulmonary disease, asthma and lower respiratory disorders, Alzheimer's disease/dementia, personality/anxiety disorders, depression, and osteoporosis. Our data suggest that nearly 7% of all hospitalizations could be avoided.

CONCLUSIONS

These findings support the need for improved outpatient care strategies to reduce the impact of comorbidity on unnecessary hospitalization in patients aged > or =65 years with type 2 diabetes.