Recommendations for Conduct, Methodological Practices, and Reporting of Cost-effectiveness Analyses: Second Panel on Cost-Effectiveness in Health and Medicine

IMPORTANCE

Since publication of the report by the Panel on Cost-Effectiveness in Health and Medicine in 1996, researchers have advanced the methods of cost-effectiveness analysis, and policy makers have experimented with its application. The need to deliver health care efficiently and the importance of using analytic techniques to understand the clinical and economic consequences of strategies to improve health have increased in recent years.

OBJECTIVE

To review the state of the field and provide recommendations to improve the quality of cost-effectiveness analyses. The intended audiences include researchers, government policy makers, public health officials, health care administrators, payers, businesses, clinicians, patients, and consumers.

DESIGN

In 2012, the Second Panel on Cost-Effectiveness in Health and Medicine was formed and included 2 co-chairs, 13 members, and 3 additional members of a leadership group. These members were selected on the basis of their experience in the field to provide broad expertise in the design, conduct, and use of cost-effectiveness analyses. Over the next 3.5 years, the panel developed recommendations by consensus. These recommendations were then reviewed by invited external reviewers and through a public posting process.

FINDINGS

The concept of a "reference case" and a set of standard methodological practices that all cost-effectiveness analyses should follow to improve quality and comparability are recommended. All cost-effectiveness analyses should report 2 reference case analyses: one based on a health care sector perspective and another based on a societal perspective. The use of an "impact inventory," which is a structured table that contains consequences (both inside and outside the formal health care sector), intended to clarify the scope and boundaries of the 2 reference case analyses is also recommended. This special communication reviews these recommendations and others concerning the estimation of the consequences of interventions, the valuation of health outcomes, and the reporting of cost-effectiveness analyses.

CONCLUSIONS AND RELEVANCE

The Second Panel reviewed the current status of the field of cost-effectiveness analysis and developed a new set of recommendations. Major changes include the recommendation to perform analyses from 2 reference case perspectives and to provide an impact inventory to clarify included consequences.

Effect of clinical decision-support systems: a systematic review

BACKGROUND

Despite increasing emphasis on the role of clinical decision-support systems (CDSSs) for improving care and reducing costs, evidence to support widespread use is lacking.

PURPOSE

To evaluate the effect of CDSSs on clinical outcomes, health care processes, workload and efficiency, patient satisfaction, cost, and provider use and implementation.

DATA SOURCES

MEDLINE, CINAHL, PsycINFO, and Web of Science through January 2011.

STUDY SELECTION

Investigators independently screened reports to identify randomized trials published in English of electronic CDSSs that were implemented in clinical settings; used by providers to aid decision making at the point of care; and reported clinical, health care process, workload, relationship-centered, economic, or provider use outcomes.

DATA EXTRACTION

Investigators extracted data about study design, participant characteristics, interventions, outcomes, and quality.

DATA SYNTHESIS

148 randomized, controlled trials were included. A total of 128 (86%) assessed health care process measures, 29 (20%) assessed clinical outcomes, and 22 (15%) measured costs. Both commercially and locally developed CDSSs improved health care process measures related to performing preventive services (n= 25; odds ratio [OR], 1.42 [95% CI, 1.27 to 1.58]), ordering clinical studies (n= 20; OR, 1.72 [CI, 1.47 to 2.00]), and prescribing therapies (n= 46; OR, 1.57 [CI, 1.35 to 1.82]). Few studies measured potential unintended consequences or adverse effects.

LIMITATIONS

Studies were heterogeneous in interventions, populations, settings, and outcomes. Publication bias and selective reporting cannot be excluded.

CONCLUSION

Both commercially and locally developed CDSSs are effective at improving health care process measures across diverse settings, but evidence for clinical, economic, workload, and efficiency outcomes remains sparse. This review expands knowledge in the field by demonstrating the benefits of CDSSs outside of experienced academic centers.

PRIMARY FUNDING SOURCE

Agency for Healthcare Research and Quality.

Cost-effectiveness of screening for HIV in the era of highly active antiretroviral therapy

BACKGROUND

The costs, benefits, and cost-effectiveness of screening for human immunodeficiency virus (HIV) in health care settings during the era of highly active antiretroviral therapy (HAART) have not been determined.

METHODS

We developed a Markov model of costs, quality of life, and survival associated with an HIV-screening program as compared with current practice. In both strategies, symptomatic patients were identified through symptom-based case finding. Identified patients started treatment when their CD4 count dropped to 350 cells per cubic millimeter. Disease progression was defined on the basis of CD4 levels and viral load. The likelihood of sexual transmission was based on viral load, knowledge of HIV status, and efficacy of counseling.

RESULTS

Given a 1 percent prevalence of unidentified HIV infection, screening increased life expectancy by 5.48 days, or 4.70 quality-adjusted days, at an estimated cost of 194 dollars per screened patient, for a cost-effectiveness ratio of 15,078 dollars per quality-adjusted life-year. Screening cost less than 50,000 dollars per quality-adjusted life-year if the prevalence of unidentified HIV infection exceeded 0.05 percent. Excluding HIV transmission, the cost-effectiveness of screening was 41,736 dollars per quality-adjusted life-year. Screening every five years, as compared with a one-time screening program, cost 57,138 dollars per quality-adjusted life-year, but was more attractive in settings with a high incidence of infection. Our results were sensitive to the efficacy of behavior modification, the benefit of early identification and therapy, and the prevalence and incidence of HIV infection.

CONCLUSIONS

The cost-effectiveness of routine HIV screening in health care settings, even in relatively low-prevalence populations, is similar to that of commonly accepted interventions, and such programs should be expanded.

Benefits and Harms of Breast Cancer Screening: A Systematic Review

IMPORTANCE

Patients need to consider both benefits and harms of breast cancer screening.

OBJECTIVE

To systematically synthesize available evidence on the association of mammographic screening and clinical breast examination (CBE) at different ages and intervals with breast cancer mortality, overdiagnosis, false-positive biopsy findings, life expectancy, and quality-adjusted life expectancy.

EVIDENCE REVIEW

We searched PubMed (to March 6, 2014), CINAHL (to September 10, 2013), and PsycINFO (to September 10, 2013) for systematic reviews, randomized clinical trials (RCTs) (with no limit to publication date), and observational and modeling studies published after January 1, 2000, as well as systematic reviews of all study designs. Included studies (7 reviews, 10 RCTs, 72 observational, 1 modeling) provided evidence on the association between screening with mammography, CBE, or both and prespecified critical outcomes among women at average risk of breast cancer (no known genetic susceptibility, family history, previous breast neoplasia, or chest irradiation). We used summary estimates from existing reviews, supplemented by qualitative synthesis of studies not included in those reviews.

FINDINGS

Across all ages of women at average risk, pooled estimates of association between mammography screening and mortality reduction after 13 years of follow-up were similar for 3 meta-analyses of clinical trials (UK Independent Panel: relative risk [RR], 0.80 [95% CI, 0.73-0.89]; Canadian Task Force: RR, 0.82 [95% CI, 0.74-0.94]; Cochrane: RR, 0.81 [95% CI, 0.74-0.87]); were greater in a meta-analysis of cohort studies (RR, 0.75 [95% CI, 0.69 to 0.81]); and were comparable in a modeling study (CISNET; median RR equivalent among 7 models, 0.85 [range, 0.77-0.93]). Uncertainty remains about the magnitude of associated mortality reduction in the entire US population, among women 40 to 49 years, and with annual screening compared with biennial screening. There is uncertainty about the magnitude of overdiagnosis associated with different screening strategies, attributable in part to lack of consensus on methods of estimation and the importance of ductal carcinoma in situ in overdiagnosis. For women with a first mammography screening at age 40 years, estimated 10-year cumulative risk of a false-positive biopsy result was higher (7.0% [95% CI, 6.1%-7.8%]) for annual compared with biennial (4.8% [95% CI, 4.4%-5.2%]) screening. Although 10-year probabilities of false-positive biopsy results were similar for women beginning screening at age 50 years, indirect estimates of lifetime probability of false-positive results were lower. Evidence for the relationship between screening and life expectancy and quality-adjusted life expectancy was low in quality. There was no direct evidence for any additional mortality benefit associated with the addition of CBE to mammography, but observational evidence from the United States and Canada suggested an increase in false-positive findings compared with mammography alone, with both studies finding an estimated 55 additional false-positive findings per extra breast cancer detected with the addition of CBE.

CONCLUSIONS AND RELEVANCE

For women of all ages at average risk, screening was associated with a reduction in breast cancer mortality of approximately 20%, although there was uncertainty about quantitative estimates of outcomes for different breast cancer screening strategies in the United States. These findings and the related uncertainty should be considered when making recommendations based on judgments about the balance of benefits and harms of breast cancer screening.

Cost-effectiveness of implantable cardioverter-defibrillators

BACKGROUND

Eight randomized trials have evaluated whether the prophylactic use of an implantable cardioverter-defibrillator (ICD) improves survival among patients who are at risk for sudden death due to left ventricular systolic dysfunction but who have not had a life-threatening ventricular arrhythmia. We assessed the cost-effectiveness of the ICD in the populations represented in these primary-prevention trials.

METHODS

We developed a Markov model of the cost, quality of life, survival, and incremental cost-effectiveness of the prophylactic implantation of an ICD, as compared with control therapy, among patients with survival and mortality rates similar to those in each of the clinical trials. We modeled the efficacy of the ICD as a reduction in the relative risk of death on the basis of the hazard ratios reported in the individual clinical trials.

RESULTS

Use of the ICD increased lifetime costs in every trial. Two trials--the Coronary Artery Bypass Graft (CABG) Patch Trial and the Defibrillator in Acute Myocardial Infarction Trial (DINAMIT)--found that the prophylactic implantation of an ICD did not reduce the risk of death and thus was both more expensive and less effective than control therapy. For the other six trials--the Multicenter Automatic Defibrillator Implantation Trial (MADIT) I, MADIT II, the Multicenter Unsustained Tachycardia Trial (MUSTT), the Defibrillators in Non-Ischemic Cardiomyopathy Treatment Evaluation (DEFINITE) trial, the Comparison of Medical Therapy, Pacing, and Defibrillation in Heart Failure (COMPANION) trial, and the Sudden Cardiac Death in Heart Failure Trial (SCD-HeFT)--the use of an ICD was projected to add between 1.01 and 2.99 quality-adjusted life-years (QALY) and between 68,300 dollars and 101,500 dollars in cost. Using base-case assumptions, we found that the cost-effectiveness of the ICD as compared with control therapy in these six populations ranged from 34,000 dollars to 70,200 dollars per QALY gained. Sensitivity analyses showed that this cost-effectiveness ratio would remain below 100,000 dollars per QALY as long as the ICD reduced mortality for seven or more years.

CONCLUSIONS

Prophylactic implantation of an ICD has a cost-effectiveness ratio below 100,000 dollars per QALY gained in populations in which a significant device-related reduction in mortality has been demonstrated.

Evaluating human papillomavirus vaccination programs

Human papillomavirus (HPV) has been implicated as the primary etiologic agent of cervical cancer. Potential vaccines against high-risk HPV types are in clinical trials. We evaluated vaccination programs with a vaccine against HPV-16 and HPV-18. We developed disease transmission models that estimated HPV prevalence and infection rates for the population overall, by age group, by level of sexual activity within each age group, and by sex. Data were based on clinical trials and published and unpublished sources. An HPV-16/18 vaccine for 12-year-old girls would reduce cohort cervical cancer cases by 61.8%, with a cost-effectiveness ratio of 14,583 dollars per quality-adjusted life year (QALY). Including male participants in a vaccine rollout would further reduce cervical cancer cases by 2.2% at an incremental cost-effectiveness ratio of 442,039 dollars/QALY compared to female-only vaccination. Vaccination against HPV-16 and HPV-18 can be cost-effective, although including male participants in a vaccination program is generally not cost-effective, compared to female-only vaccination.

Systematic review of the incidence of sudden cardiac death in the United States

The need for consistent and current data describing the true incidence of sudden cardiac arrest (SCA) and/or sudden cardiac death (SCD) was highlighted during the most recent Sudden Cardiac Arrest Thought Leadership Alliance's (SCATLA) Think Tank meeting of national experts with broad representation of key stakeholders, including thought leaders and representatives from the American College of Cardiology, American Heart Association, and the Heart Rhythm Society. As such, to evaluate the true magnitude of this public health problem, we performed a systematic literature search in MEDLINE using the MeSH headings, "death, sudden" OR the terms "sudden cardiac death" OR "sudden cardiac arrest" OR "cardiac arrest" OR "cardiac death" OR "sudden death" OR "arrhythmic death." Study selection criteria included peer-reviewed publications of primary data used to estimate SCD incidence in the U.S. We used Web of Science's Cited Reference Search to evaluate the impact of each primary estimate on the medical literature by determining the number of times each "primary source" has been cited. The estimated U.S. annual incidence of SCD varied widely from 180,000 to >450,000 among 6 included studies. These different estimates were in part due to different data sources (with data age ranging from 1980 to 2007), definitions of SCD, case ascertainment criteria, methods of estimation/extrapolation, and sources of case ascertainment. The true incidence of SCA and/or SCD in the U.S. remains unclear, with a wide range in the available estimates that are badly dated. As reliable estimates of SCD incidence are important for improving risk stratification and prevention, future efforts are clearly needed to establish uniform definitions of SCA and SCD and then to prospectively and precisely capture cases of SCA and SCD in the overall U.S. population.

Cost-effectiveness of a potential vaccine for human papillomavirus

Human papillomavirus (HPV) infection, usually a sexually transmitted disease, is a risk factor for cervical cancer. Given the substantial disease and death associated with HPV and cervical cancer, development of a prophylactic HPV vaccine is a public health priority. We evaluated the cost-effectiveness of vaccinating adolescent girls for high-risk HPV infections relative to current practice. A vaccine with a 75% probability of immunity against high-risk HPV infection resulted in a life-expectancy gain of 2.8 days or 4.0 quality-adjusted life days at a cost of $246 relative to current practice (incremental cost effectiveness of $22,755/quality-adjusted life year [QALY]). If all 12-year-old girls currently living in the United States were vaccinated, >1,300 deaths from cervical cancer would be averted during their lifetimes. Vaccination of girls against high-risk HPV is relatively cost effective even when vaccine efficacy is low. If the vaccine efficacy rate is 35%, the cost effectiveness increases to $52,398/QALY. Although gains in life expectancy may be modest at the individual level, population benefits are substantial.

Oral contraceptive use and risk of breast, cervical, colorectal, and endometrial cancers: a systematic review

Oral contraceptives may influence the risk of certain cancers. As part of the AHRQ Evidence Report, Oral Contraceptive Use for the Primary Prevention of Ovarian Cancer, we conducted a systematic review to estimate associations between oral contraceptive use and breast, cervical, colorectal, and endometrial cancer incidence. We searched PubMed, Embase, and Cochrane Database of Systematic Reviews. Study inclusion criteria were women taking oral contraceptives for contraception or ovarian cancer prevention; includes comparison group with no oral contraceptive use; study reports quantitative associations between oral contraceptive exposure and relevant cancers; controlled study or pooled patient-level meta-analyses; sample size for nonrandomized studies ≥100; peer-reviewed, English-language; published from January 1, 2000 forward. Random-effects meta-analyses were conducted by estimating pooled ORs with 95% confidence intervals (CIs). We included 44 breast, 12 cervical, 11 colorectal, and 9 endometrial cancers studies. Breast cancer incidence was slightly but significantly increased in users (OR, 1.08; CI, 1.00-1.17); results show a higher risk associated with more recent use of oral contraceptives. Risk of cervical cancer was increased with duration of oral contraceptive use in women with human papillomavirus infection; heterogeneity prevented meta-analysis. Colorectal cancer (OR, 0.86; CI, 0.79-0.95) and endometrial cancer incidences (OR, 0.57; CI, 0.43-0.77) were significantly reduced by oral contraceptive use. Compared with never use, ever use of oral contraceptives is significantly associated with decreases in colorectal and endometrial cancers and increases in breast cancers. Although elevated breast cancer risk was small, relatively high incidence of breast cancers means that oral contraceptives may contribute to a substantial number of cases.

Elderly humans exposed to concentrated air pollution particles have decreased heart rate variability

Air pollution particles are thought to kill > 500,000 people worldwide each year. The population most at risk appears to be elderly people with respiratory and cardiovascular disease. As yet, no commonly accepted mechanism has been proposed which can explain the cause of these deaths. Heart rate variability (HRV) was assessed in healthy elderly adults between the ages of 60 and 80 who were exposed twice for 2 h: once to clean air and once to concentrated ambient air pollution particles (CAPS). Changes in HRV were measured immediately before, immediately following, and 24 h after exposure. Elderly subjects experienced significant decreases in HRV in both time and frequency domains immediately following exposure. Some of these changes persisted for at least 24 h. These data were compared with HRV data collected from young healthy volunteers exposed to CAPS in a previous study, in which no CAPS-induced changes in HRV were found. These concentrated ambient air pollution particle-induced changes in heart rate variability in a controlled human exposure study extend similar findings reported in recent panel studies and suggest potential mechanisms by which particulate matter may induce adverse cardiovascular events.

Non-evidence-based ICD implantations in the United States

CONTEXT

Practice guidelines do not recommend use of an implantable cardioverter-defibrillator (ICD) for primary prevention in patients recovering from a myocardial infarction or coronary artery bypass graft surgery and those with severe heart failure symptoms or a recent diagnosis of heart failure.

OBJECTIVE

To determine the number, characteristics, and in-hospital outcomes of patients who receive a non-evidence-based ICD and examine the distribution of these implants by site, physician specialty, and year of procedure.

DESIGN, SETTING, AND PATIENTS

Retrospective cohort study of cases submitted to the National Cardiovascular Data Registry-ICD Registry between January 1, 2006, and June 30, 2009.

MAIN OUTCOME MEASURE

In-hospital outcomes.

RESULTS

Of 111,707 patients, 25,145 received non-evidence-based ICD implants (22.5%). Patients who received a non-evidence-based ICD compared with those who received an evidence-based ICD had a significantly higher risk of in-hospital death (0.57% [95% confidence interval {CI}, 0.48%-0.66%] vs 0.18% [95% CI, 0.15%-0.20%]; P <.001) and any postprocedure complication (3.23% [95% CI, 3.01%-3.45%] vs 2.41% [95% CI, 2.31%-2.51%]; P <.001). There was substantial variation in non-evidence-based ICDs by site. The rate of non-evidence-based ICD implants was significantly lower for electrophysiologists (20.8%; 95% CI, 20.5%-21.1%) than nonelectrophysiologists (24.8% [95% CI, 24.2%-25.3%] for nonelectrophysiologist cardiologists; 36.1% [95% CI, 34.3%-38.0%] for thoracic surgeons; and 24.9% [95% CI, 23.8%-25.9%] for other specialties) (P<.001 for all comparisons). There was no clear decrease in the rate of non-evidence-based ICDs over time (24.5% [6908/28,233] in 2006, 21.8% [7395/33,965] in 2007, 22.0% [7245/32,960] in 2008, and 21.7% [3597/16,549] in 2009; P <.001 for trend from 2006-2009 and P = .94 for trend from 2007-2009).

CONCLUSION

Among patients with ICD implants in this registry, 22.5% did not meet evidence-based criteria for implantation.

Low-molecular-weight heparins compared with unfractionated heparin for treatment of acute deep venous thrombosis. A cost-effectiveness analysis

BACKGROUND

Low-molecular-weight heparins are effective for treating venous thrombosis, but their cost-effectiveness has not been rigorously assessed.

OBJECTIVE

To evaluate the cost-effectiveness of low-molecular-weight heparins compared with unfractionated heparin for treatment of acute deep venous thrombosis.

DESIGN

Decision model.

DATA SOURCES

Probabilities for clinical outcomes were obtained from a meta-analysis of randomized trials. Cost estimates were derived from Medicare reimbursement and other sources.

TARGET POPULATION

Two hypothetical cohorts of 60-year-old men with acute deep venous thrombosis.

TIME HORIZON

Patient lifetime.

PERSPECTIVE

Societal.

INTERVENTION

Fixed-dose low-molecular-weight heparin or adjusted-dose unfractionated heparin.

OUTCOME MEASURES

Costs, quality-adjusted life-years (QALYs), and incremental cost-effectiveness ratios. An in-patient hospital setting was used for the base-case analysis. Secondary analyses examined outpatient treatment with low-molecular-weight heparin.

RESULTS OF BASE-CASE ANALYSIS

Total costs for inpatient treatment were $26,516 for low-molecular-weight heparin and $26,361 for unfractionated heparin. The cost of initial care was higher in patients who received low-molecular-weight heparin, but this was partly offset by reduced costs for early complications. Low-molecular-weight heparin treatment increased quality-adjusted life expectancy by approximately 0.02 years. The incremental cost-effectiveness of inpatient low-molecular-weight heparin treatment was $7820 per QALY gained. Treatment with low-molecular-weight heparin was cost saving when as few as 8% of patients were treated at home.

RESULTS OF SENSITIVITY ANALYSIS

When late complications were assumed to occur 25% less frequently in patients who received unfractionated heparin, the incremental cost-effectiveness ratio increased to almost $75,000 per QALY gained. When late complications were assumed to occur 25% less frequently in patients who received low-molecular-weight heparin, this treatment resulted in a net cost savings. Inpatient low-molecular-weight heparin treatment became cost saving when its pharmacy cost was reduced by 31% or more, when it reduced the yearly incidence of late complications by at least 7%, when as few as 8% of patients were treated entirely as outpatients, or when at least 13% of patients were eligible for early discharge.

CONCLUSIONS

Low-molecular-weight heparins are highly cost-effective for inpatient management of venous thrombosis. This treatment reduces costs when small numbers of patients are eligible for outpatient management.

Oral contraceptives and risk of ovarian cancer and breast cancer among high-risk women: a systematic review and meta-analysis

PURPOSE

To estimate the risks of ovarian cancer and breast cancer associated with oral contraceptive (OC) use among women at elevated risk owing to mutations in BRCA1/2 or a strong family history.

METHODS

We searched PubMed, Embase, the Cochrane Database of Systematic Reviews, and ClinicalTrials.gov for studies published 2000 to 2012 that evaluated associations between OC use and breast or ovarian cancer among women who are carriers of a BRCA1/2 mutation or have a family history of breast or ovarian cancer.

RESULTS

From 6,476 unique citations, we identified six studies examining ovarian cancer risk in BRCA1/2 mutation carriers and eight studies examining breast cancer risk in BRCA1/2 mutation carriers. For BRCA1/2 mutation carriers combined, meta-analysis showed an inverse association between OC use and ovarian cancer (odds ratio [OR], 0.58; 95% CI, 0.46 to 0.73) and a nonstatistically significant association with breast cancer (OR, 1.21; 95% CI, 0.93 to 1.58). Findings were similar when examining BRCA1 and BRCA2 mutation carriers separately. Data were inadequate to perform meta-analyses examining duration or timing of use. For women with a family history of ovarian or breast cancer, we identified four studies examining risk for ovarian cancer and three for breast cancer, but differences between studies precluded combining the data for meta-analyses, and no overall pattern could be discerned.

CONCLUSION

Our analyses suggest that associations between ever use of OCs and ovarian and breast cancer among women who are BRCA1 or BRCA2 mutation carriers are similar to those reported for the general population.

The 2nd to 4th digit ratio and autism

It has been suggested that autism may arise as the result of exposure to high concentrations of prenatal testosterone. There is evidence that the ratio of the lengths of the 2nd and 4th digit (2D:4D) may be negatively correlated with prenatal testosterone. We measured 2D:4D in 95 families recruited via the National Autistic Society, UK. The sample comprised a total 72 children with autism (62 males, 10 females; age range 2 to 14 years), including 23 children (20 males, three females) with Asperger syndrome (AS), 34 siblings, 88 fathers, 88 mothers and sex- and age-matched control participants. We found that the 2D:4D ratios of children with autism, their siblings, fathers and mothers were lower than population normative values. Children with AS, who share the social and communicative symptoms of autism but have normal or even high IQ, had higher 2D:4D ratios than children with autism but lower ratios than population normative values. There were positive associations between 2D:4D ratios of children with autism and the ratios of their relatives. Children with autism had lower than expected 2D:4D ratios and children with AS higher ratios than expected in relation to their fathers' 2D:4D ratio. It was concluded that 2D:4D ratio may be a possible marker for autism which could implicate prenatal testosterone in its aetiology.

Predicting Thromboembolic and Bleeding Event Risk in Patients with Non-Valvular Atrial Fibrillation: A Systematic Review

BACKGROUND

 Atrial fibrillation (AF) is a common cardiac arrhythmia that increases the risk of stroke. Medical therapy for decreasing stroke risk involves anticoagulation, which may increase bleeding risk for certain patients. In determining the optimal therapy for stroke prevention for patients with AF, clinicians use tools with various clinical, imaging and patient characteristics to weigh stroke risk against therapy-associated bleeding risk.

AIM

 This article reviews published literature and summarizes available risk stratification tools for stroke and bleeding prediction in patients with AF.

METHODS

 We searched for English-language studies in PubMed, Embase and the Cochrane Database of Systematic Reviews published between 1 January 2000 and 14 February 2018. Two reviewers screened citations for studies that examined tools for predicting thromboembolic and bleeding risks in patients with AF. Data regarding study design, patient characteristics, interventions, outcomes, quality, and applicability were extracted.

RESULTS

 Sixty-one studies were relevant to predicting thromboembolic risk and 38 to predicting bleeding risk. Data suggest that CHADS₂, CHA₂DS₂-VASc and the age, biomarkers, and clinical history (ABC) risk scores have the best evidence for predicting thromboembolic risk (moderate strength of evidence for limited prediction ability of each score) and that HAS-BLED has the best evidence for predicting bleeding risk (moderate strength of evidence).

LIMITATIONS

 Studies were heterogeneous in methodology and populations of interest, setting, interventions and outcomes analysed.

CONCLUSION

 CHADS₂, CHA₂DS₂-VASc and ABC scores have the best prediction for stroke events, and HAS-BLED provides the best prediction for bleeding risk. Future studies should define the role of imaging tools and biomarkers in enhancing the accuracy of risk prediction tools.

PRIMARY FUNDING SOURCE

 Patient-Centered Outcomes Research Institute (PROSPERO #CRD42017069999).

Estimation of arterial stiffness, compliance, and distensibility from M-mode ultrasound measurements of the common carotid artery

BACKGROUND AND PURPOSE

Arterial stiffness may indicate early vascular changes that predispose to the development of major vascular disease. The repeatability of a variety of indices of arterial stiffness calculated from a standard carotid arterial M-mode ultrasound image was investigated.

METHODS

Twenty-six asymptomatic normal subjects were imaged and had blood pressure recordings on each of two separate occasions at least 1 day apart. Using a computer-assisted method, the maximum and minimum internal diameter and average wall thickness of the right common carotid artery were measured over several cardiac cycles, and the following indices of arterial stiffness and distensibility (compliance) were derived: the pressure-strain elastic modulus (Ep), Young's modulus (E), cross-sectional compliance (CC), and the distensibility coefficient (DC).

RESULTS

The repeatability of these measures, expressed as coefficients of variation, was as follows: Ep, 18%; E, 24%; CC, 14%; and DC, 13%. In another group of 20 subjects, the coefficient of variation for repeat examination by different sonographers was Ep, 19%; E, 20%; CC, 14%; and DC, 17% and for the one sonographer using two ultrasound machines was Ep, 13%; E, 13%; CC, 11%; and DC, 13%. These values indicate a moderate level of repeatability. In a univariate analysis each of these indices was significantly related to increasing age (Ep = 1.0 + 12.9 x AGE, r = .80; E = 314.5 + 13.9 x AGE, r = .48; CC = 22.6-0.26 x AGE, r = -.63; DC = 64.0-0.65 x AGE, r = -.78) but not to wall thickness (all P > .47). Using multiple regression techniques to adjust for age, wall thickness is a significant predictor of distensibility (P = .017), cross-sectional compliance (P < .001), and the pressure-strain elastic modulus (P = .019). Because Young's modulus is calculated from wall thickness, it could not be included in the multivariate analysis.

CONCLUSIONS

We conclude that estimates of carotid artery distensibility and cross-sectional compliance derived from M-mode ultrasound recordings are moderately repeatable and may provide useful additional end points for trials of atherosclerotic progression.

Left hand advantage in a self-face recognition task

Subjects were exposed to pictures of self and others (e.g., friend, stranger, and famous people) to determine if there was an advantage in reaction time and accuracy in identifying the self. It was found that upright and inverted self-faces were identified more rapidly than non-self faces when subjects responded with their left hand, which in other tasks has corresponded with contralateral hemispheric dominance. These data suggest that self-recognition may be correlated with neural activity in the right hemisphere, and that the differences observed may not be unique to self-face recognition. These results are in agreement with previous research indicating that self-directed awareness is correlated with right prefrontal activity.

Thin aggregative fimbriae enhance Salmonella enteritidis biofilm formation

Salmonella enteritidis enteropathogens produce a variety of potentially adherent fimbrial types including SEF14, SEF17, SEF18 and SEF21 (type I). In a simplified, pure culture, biofilm generating system the virulent isolate, S. enteritidis 3b, readily adhered to Teflon (polytetrafluoroethylene) and stainless steel forming thick cell aggregates. The inability of an isogenic SEF17-deficient mutant to form thick biofilms suggested a role for SEF17 in stabilizing cell-cell interactions during biofilm formation. Epifluorescent detection of SEF17 in biofilms confirmed the association of these fimbriae with aggregated cells but not with adherent mutants unable to produce SEF17. The reduced adherence observed with an isogenic SEF14/SEF21-deficient strain implicated the involvement of additional cell surface adherence factors, possibly including SEF21 (type I) fimbriae in the adherence of S. enteritidis to stainless steel or Teflon. The role of SEF17 fimbriae in biofilm formation and the contributions of SEF17 to the persistence of Salmonellae on surfaces and in food are discussed.

Adsorption, attachment and biofilm formation among isolates of Listeria monocytogenes using model conditions

AIMS

To determine whether isolates of Listeria monocytogenes differ in their ability to adsorb and form biofilms on a food-grade stainless steel surface.

METHODS AND RESULTS

Strains were assessed for their ability to adsorb to a test surface over a short time period. Although some differences in numbers of bound cells were found among the strains, there were no correlations between the degree of adsorption and either the serotype or source of the strain. The ability of each strain to form a biofilm when grown with the test surface was also assessed. With the exception of a single strain, all strains adhered as single cells and did not form biofilms. Significant differences in adherence levels were found among strains. Strains demonstrating enhanced attachment produced extracellular fibrils, whereas those which adhered poorly did not. A single strain formed a biofilm consisting of adhered single cells and aggregates of cells.

CONCLUSIONS

Significant differences were found in the ability of various L. monocytogenes strains to attach to a test surface. In monoculture, the majority of strains did not form biofilms.

SIGNIFICANCE AND IMPACT OF THE STUDY

Differences in attachment and biofilm formation among strains provide a basis to study these characteristics in L. monocytogenes.

Cost-effectiveness of alternative management strategies for patients with solitary pulmonary nodules

BACKGROUND

Positron emission tomography (PET) with 18-fluorodeoxyglucose (FDG) is a potentially useful but expensive test to diagnose solitary pulmonary nodules.

OBJECTIVE

To evaluate the cost-effectiveness of strategies for pulmonary nodule diagnosis and to specifically compare strategies that did and did not include FDG-PET.

DESIGN

Decision model.

DATA SOURCES

Accuracy and complications of diagnostic tests were estimated by using meta-analysis and literature review. Modeled survival was based on data from a large tumor registry. Cost estimates were derived from Medicare reimbursement and other sources.

TARGET POPULATION

All adult patients with a new, noncalcified pulmonary nodule seen on chest radiograph.

TIME HORIZON

Patient lifetime.

PERSPECTIVE

Societal.

INTERVENTION

40 clinically plausible combinations of 5 diagnostic interventions, including computed tomography, FDG-PET, transthoracic needle biopsy, surgery, and watchful waiting.

OUTCOME MEASURES

Costs, quality-adjusted life-years (QALYs), and incremental cost-effectiveness ratios.

RESULTS OF BASE-CASE ANALYSIS

The cost-effectiveness of strategies depended critically on the pretest probability of malignancy. For patients with low pretest probability (26%), strategies that used FDG-PET selectively when computed tomography results were possibly malignant cost as little as 20 000 dollars per QALY gained. For patients with high pretest probability (79%), strategies that used FDG-PET selectively when computed tomography results were benign cost as little as 16 000 dollars per QALY gained. For patients with intermediate pretest probability (55%), FDG-PET strategies cost more than 220 000 dollars per QALY gained because they were more costly but only marginally more effective than computed tomography-based strategies.

RESULTS OF SENSITIVITY ANALYSIS

The choice of strategy also depended on the risk for surgical complications, the probability of nondiagnostic needle biopsy, the sensitivity of computed tomography, and patient preferences for time spent in watchful waiting. In probabilistic sensitivity analysis, FDG-PET strategies were cost saving or cost less than 100 000 dollars per QALY gained in 76.7%, 24.4%, and 99.9% of computer simulations for patients with low, intermediate, and high pretest probability, respectively.

CONCLUSIONS

FDG-PET should be used selectively when pretest probability and computed tomography findings are discordant or in patients with intermediate pretest probability who are at high risk for surgical complications. In most other circumstances, computed tomography-based strategies result in similar quality-adjusted life-years and lower costs.

Rate- and rhythm-control therapies in patients with atrial fibrillation: a systematic review

BACKGROUND

The comparative effectiveness of treatments for atrial fibrillation (AF) is uncertain.

PURPOSE

To evaluate the comparative effectiveness of rate- and rhythm-control therapies.

DATA SOURCES

English-language studies in PubMed, EMBASE, and the Cochrane Database of Systematic Reviews between January 2000 and November 2013.

STUDY SELECTION

Two reviewers independently screened citations to identify comparative studies that assessed rate- or rhythm-control therapies in patients with AF.

DATA EXTRACTION

Reviewers extracted data on study design, participant characteristics, interventions, outcomes, applicability, and quality.

DATA SYNTHESIS

200 articles (162 studies) involving 28,836 patients were included. When pharmacologic rate- and rhythm-control strategies were compared, strength of evidence (SOE) was moderate supporting comparable efficacy with regard to all-cause mortality (odds ratio [OR], 1.34 [95% CI, 0.89 to 2.02]), cardiac mortality (OR, 0.96 [CI, 0.77 to 1.20]), and stroke (OR, 0.99 [CI, 0.76 to 1.30]) in older patients with mild AF symptoms. Few studies compared rate-control therapies and included outcomes of interest, which limited conclusions. For the effect of rhythm-control therapies in reducing AF recurrence, SOE was high favoring pulmonary vein isolation versus antiarrhythmic medications (OR, 5.87 [CI, 3.18 to 10.85]) and the surgical maze procedure (including pulmonary vein isolation) done during other cardiac surgery versus other cardiac surgery alone (OR, 7.94 [CI, 3.63 to 17.36]).

LIMITATION

Studies were heterogeneous in interventions, populations, settings, and outcomes.

CONCLUSION

Pharmacologic rate- and rhythm-control strategies have comparable efficacy across outcomes in primarily older patients with mild AF symptoms. Pulmonary vein isolation is better than antiarrhythmic medications at reducing recurrences of AF in younger patients with paroxysmal AF and mild structural heart disease. Future research should address uncertainties related to subgroups of interest and the effect of different therapies on long-term clinical outcomes.

PRIMARY FUNDING SOURCE

Agency for Healthcare Research and Quality.

Cost-effectiveness of implantable cardioverter defibrillators relative to amiodarone for prevention of sudden cardiac death

BACKGROUND

Implantable cardioverter defibrillators (ICDs) are remarkably effective in terminating ventricular arrhythmias, but they are expensive and the extent to which they extend life is unknown. The marginal cost-effectiveness of ICDs relative to amiodarone has not been clearly established.

OBJECTIVE

To compare the cost-effectiveness of a third-generation implantable ICD with that of empirical amiodarone treatment for preventing sudden cardiac death in patients at high or intermediate risk.

DESIGN

A Markov model was used to evaluate health and economic outcomes of patients who received an ICD, amiodarone, or a sequential regimen that reserved ICD for patients who had an arrhythmia during amiodarone treatment.

MEASUREMENTS

Life-years gained, quality-adjusted life-years gained, costs, and marginal cost-effectiveness.

RESULTS

For the base-case analysis, it was assumed that treatment with an ICD would reduce the total mortality rate by 20% to 40% at 1 year compared with amiodarone and that the ICD generator would be replaced every 4 years. In high-risk patients, if an ICD reduces total mortality by 20%, patients who receive an ICD live for 4.18 quality-adjusted life-years and have a lifetime expenditure of $88,400. Patients receiving amiodarone live for 3.68 quality-adjusted life-years and have a lifetime expenditure of $51,000. Marginal cost-effectiveness of an ICD relative to amiodarone is $74,400 per quality-adjusted life-year saved. If an ICD reduces mortality by 40%, the cost-effectiveness of ICD use is $37,300 per quality-adjusted life-year saved. Both choice of therapy (an ICD or amiodarone) and the cost-effectiveness ratio are sensitive to assumptions about quality of life.

CONCLUSIONS

Use of an ICD will cost more than $50,000 per quality-adjusted life-year gained unless it reduces all-cause mortality by 30% or more relative to amiodarone. Current evidence does not definitively support or exclude a benefit of this magnitude, but ongoing randomized trials have sufficient statistical power to do so.

Cost-effectiveness of screening for hepatocellular carcinoma in patients with cirrhosis due to chronic hepatitis C

BACKGROUND

Screening for hepatocellular carcinoma in cirrhotic patients using abdominal ultrasonography and alpha-foetoprotein levels is widely practiced.

AIM

To evaluate its cost-effectiveness using a Markov decision model.

METHODS

Several screening strategies with abdominal ultrasonography or computerized tomography and serum alpha-foetoprotein at 6-12-month intervals in 40-year-old patients with chronic hepatitis C and compensated cirrhosis were simulated from a societal perspective, resulting in discounted costs per quality-adjusted life-year saved. Extensive sensitivity analysis was performed.

RESULTS

For the least efficacious strategy, annual alpha-foetoprotein/ultrasonography, the incremental cost-effectiveness ratio (vs. no screening) was $23 043/quality-adjusted life-year. Biannual alpha-foetoprotein/annual ultrasonography, the most commonly used strategy in the United States, was more efficacious, with a cost-effectiveness ratio of $33 083/quality-adjusted life-year vs. annual alpha-foetoprotein/ultrasonography. The most efficacious strategy, biannual alpha-foetoprotein/ultrasonography, resulted in a cost-effectiveness ratio of $73 789/quality-adjusted life-year vs. biannual alpha-foetoprotein/annual ultrasonography. Biannual alpha-foetoprotein/annual computerized tomography screening resulted in a cost-effectiveness ratio of $51 750/quality-adjusted life-year vs. biannual alpha-foetoprotein/annual ultrasonography screening.

CONCLUSIONS

Screening for hepatocellular carcinoma is as cost-effective as other accepted screening protocols. Of the strategies evaluated, biannual alpha-foetoprotein/annual ultrasonography gives the most quality-adjusted life-year gain while still maintaining a cost-effectiveness ratio <$50 000/quality-adjusted life-year. Biannual alpha-foetoprotein/annual computerized tomography screening may be cost-effective.

An economic evaluation of prolonged mechanical ventilation

OBJECTIVE

Patients who receive prolonged mechanical ventilation have high resource utilization and relatively poor outcomes, especially the elderly, and are increasing in number. The economic implications of prolonged mechanical ventilation provision, however, are uncertain and would be helpful to providers and policymakers. Therefore, we aimed to determine the lifetime societal value of prolonged mechanical ventilation.

DESIGN AND PATIENTS

Adopting the perspective of a healthcare payor, we developed a Markov model to determine the cost effectiveness of providing mechanical ventilation for at least 21 days to a 65-yr-old critically ill base-case patient compared with the provision of comfort care resulting in withdrawal of ventilation. Input data were derived from the medical literature, Medicare, and a recent large cohort study of ventilated patients.

MEASUREMENTS AND MAIN RESULTS

We determined lifetime costs and survival, quality-adjusted life expectancy, and cost effectiveness as reflected by costs per quality-adjusted life-year gained. Providing prolonged mechanical ventilation to the base-case patient cost "dollars"55,460 per life-year gained and "dollars"82,411 per quality-adjusted life-year gained compared with withdrawal of ventilation. Cost-effectiveness ratios were most sensitive to variation in age, hospital costs, and probability of readmission, although less sensitive to postacute care-facility costs. Specifically, incremental costs per quality-adjusted life-year gained by prolonged mechanical ventilation provision exceeded "dollars"100,000 with age >or=68 and when predicted 1-yr mortality was >50%.

CONCLUSIONS

The cost effectiveness of prolonged mechanical ventilation provision varies dramatically based on age and likelihood of poor short- and long-term outcomes. Identifying patients likely to have unfavorable outcomes, lowering intensity of care for appropriate patients, and reducing costly readmissions should be future priorities in improving the value of prolonged mechanical ventilation.