Terms Of Mortality Risk Research Articles

Aortic Dissection: Novel Surgical Hybrid Procedures.

The management of patients with aortic dissection is challenging and its treatment is an area of development and innovation. Conventional surgical techniques are associated with significant risks in terms of mortality and morbidity in such high-risk patients. As a result of cumulative advances in technology, classical surgical techniques have been improved and enhanced by the newer endovascular approaches, leading to novel surgical hybrid procedures. Impressive early results have been seen with frozen elephant techniques, revascularisation of the supra-aortic branches and branched/fenestrated thoracic endovascular aortic repair-alone procedures. This review describes the techniques involved in the latest hybrid procedures for aortic dissection and their outcomes.

Optimal Versus Realized Trajectories of Physiological Dysregulation in Aging and Their Relation to Sex-Specific Mortality Risk.

While longitudinal changes in biomarker levels and their impact on health have been characterized for individual markers, little is known about how overall marker profiles may change during aging and affect mortality risk. We implemented the recently developed measure of physiological dysregulation based on the statistical distance of biomarker profiles in the framework of the stochastic process model of aging, using data on blood pressure, heart rate, cholesterol, glucose, hematocrit, body mass index, and mortality in the Framingham original cohort. This allowed us to evaluate how physiological dysregulation is related to different aging-related characteristics such as decline in stress resistance and adaptive capacity (which typically are not observed in the data and thus can be analyzed only indirectly), and, ultimately, to estimate how such dynamic relationships increase mortality risk with age. We found that physiological dysregulation increases with age; that increased dysregulation is associated with increased mortality, and increasingly so with age; and that, in most but not all cases, there is a decreasing ability to return quickly to baseline physiological state with age. We also revealed substantial sex differences in these processes, with women becoming dysregulated more quickly but with men showing a much greater sensitivity to dysregulation in terms of mortality risk.

The Added Value of Medical Testing in Underwriting Life Insurance

BackgroundIn present-day life-insurance medical underwriting practice the risk assessment starts with a standard health declaration (SHD). Indication for additional medical screening depends predominantly on age and amount of insured capital. From a medical perspective it is questionable whether there is an association between the level of insured capital and medical risk in terms of mortality. The aim of the study is to examine the prognostic value of parameters from the health declaration and application form on extra mortality based on results from additional medical testing.MethodsA history register-based cohort study was conducted including about 15.000 application files accepted between 2007 and 2010. Blood pressure, lipids, cotinine and glucose levels were used as dependent variables in logistic regression models. Resampling validation was applied using 250 bootstrap samples to calculate area under the curves (AUC’s). The AUC was used to discriminate between persons with and without at least 25% extra mortality.ResultsBMI and the overall assessment of the health declaration by an insurance physician or medical underwriter showed the strongest discrimination in multivariable analysis. Including all variables at minimum cut-off levels resulted in an AUC of 0.710 while by using a model with BMI, the assessment of the health declaration and gender, the AUC was 0.708. Including all variables at maximum cut-off levels lead to an AUC of 0.743 while a model with BMI, the assessment of the health declaration and age resulted in an AUC of 0.741.ConclusionsThe outcome of this study shows that BMI and the overall assessment of the health declaration were the dominant variables to discriminate between applicants for life-insurance with and without at least 25 percent extra mortality. The variable insured capital set by insurers as factor for additional medical testing could not be established in this study population. The indication for additional medical testing at underwriting life-insurance can possibly be done on limited variables instead of the obligatory medical testing based on age and the amount of insured capital.

DO THE PEGASUS SELECTION CRITERIA REFLECT LONG-TERM RISK OF DEATH IN A REAL-WORLD POST-AMI POPULATION? RESULTS FROM THE FAST-MI 2005 REGISTRY

The results of PEGASUS trial, evaluating the effects of dual antiplatelet therapy in patients with prior AMI, will be presented during ACC2015. Whether the PEGASUS selection criteria adequately reflect long term risk of mortality in routine practice is questionable. FAST-MI is a nationwide French

Can property values capture changes in environmental health risks? Evidence from a stated preference study in Italy and the United Kingdom.

Hedonic models are a common nonmarket valuation technique, but, in practice, results can be affected by omitted variables and whether homebuyers respond to the assumed environmental measure. We undertake an alternative stated preference approach that circumvents these issues. We examine how homeowners in the United Kingdom and Italy value mortality risk reductions by asking them to choose among hypothetical variants of their home that differ in terms of mortality risks from air pollution and price. We find that Italian homeowners hold a value of a statistical life (VSL) of €6.4 million, but U.K. homeowners hold a much lower VSL (€2.1 million). This may be because respondents in the United Kingdom do not perceive air pollution where they live to be as threatening, and actually live in cities with relatively low air pollution. Italian homeowners value a reduction in the risk of dying from cancer more than from other causes, but U.K. respondents do not hold such a premium. Lastly, respondents who face higher baseline risks, due to greater air pollution where they live, hold a higher VSL, particularly in the United Kingdom. In both countries, the VSL is twice as large among individuals who perceive air pollution where they live as high.

Comparing life expectancy and health-adjusted life expectancy by body mass index category in adult Canadians: a descriptive study

BackgroundWhile many studies have examined differences between body mass index (BMI) categories in terms of mortality risk and health-related quality of life (HRQL), little is known about the effect of body weight on health expectancy. We examined life expectancy (LE), health-adjusted life expectancy (HALE), and proportion of LE spent in nonoptimal (or poor) health by BMI category for the Canadian adult population (age ≥ 20).MethodsRespondents to the National Population Health Survey (NPHS) were followed for mortality outcomes from 1994 to 2009. Our study population at baseline (n=12,478) was 20 to 100 years old with an average age of 47. LE was produced by building abridged life tables by sex and BMI category using data from the NPHS and the Canadian Chronic Disease Surveillance System. HALE was estimated using the Health Utilities Index from the Canadian Community Health Survey as a measure of HRQL. The contribution of HRQL to loss of healthy life years for each BMI category was also assessed using two methods: by calculating differences between LE and HALE proportional to LE and by using a decomposition technique to separate out mortality and HRQL contributions to loss of HALE.ResultsAt age 20, for both sexes, LE is significantly lower in the underweight and obesity class 2+ categories, but significantly higher in the overweight category when compared to normal weight (obesity class 1 was nonsignificant). HALE at age 20 follows these same associations and is significantly lower for class 1 obesity in women. Proportion of life spent in nonoptimal health and decomposition of HALE demonstrate progressively higher losses of healthy life associated with lowered HRQL for BMI categories in excess of normal weight.ConclusionsAlthough being in the overweight category for adults may be associated with a gain in life expectancy as compared to normal weight adults, overweight individuals also experience a higher proportion of these years of life in poorer health. Due to the descriptive nature of this study, further research is needed to explore the causal mechanisms which explain these results, including the important differences we observed between sexes and within obesity subcategories.

What are the key challenges we face in kidney transplantation today?

Transplantation is more predictable than it was 20 to 30 years ago and innovation over the last 20 years has been rapid, delivering substantial short-term and medium-term improvements. The challenges ahead are to deliver improved results globally in the context of also preventing chronic disease and reducing the costs of treatment. Countries achieving the best rates of transplantation combine deceased and living donors and can transplant more than 50 people per annum per million population, so why can this not be achieved everywhere? The mortality rates have dropped, but they are still up to 10-fold worse than age- and sex-matched controls, such that transplantation ages individuals by 30 years in terms of mortality risk. Cardiovascular disease, infection and malignancy remain the targets if mortality is to normalize. Graft survival rates will not change until the multiple injuries constituting chronic allograft dysfunction and the problems of recurrent disease can be brought to heel. Biomarkers may provide the next innovation to advance outcomes, but early experimental tolerance protocols implemented in clinical practice in at least three centers may deliver results more quickly.

Can Property Values Capture Changes in Environmental Health Risks? Evidence from a Stated Preference Study in Italy and the UK

Hedonic property value models are often used to place a value on localized amenities and disamenities. In practice, however, results may be affected by (i) omitted variable bias and (ii) whether homebuyers and sellers are aware of, and respond to, the assumed environmental measure. In this paper we undertake an alternative stated preference (SP) approach that eliminates the potential for unobserved confounders and where the measure of environmental quality is explicitly presented to respondents. We examine how homeowners in the United Kingdom and Italy value mortality risk reductions by asking them to choose among hypothetical variants of their home that differ in terms of mortality risks from air pollution and price. To our knowledge this is the first stated preference study examining respondents’ willingness to pay for properties using a quantitative and clearly specified measure of health risks. We find that Italian homeowners hold a value of a statistical life (VSL) of about €6.4 million, but UK homeowners tend to hold a much lower VSL (€2.1 million). This may be due to the fact that respondents in the UK do not perceive air pollution where they live to be as threatening, and actually live in cities with relatively low air pollution levels. Exploiting part of our experimental design, we find that Italian homeowners value a reduction in the risk of dying from cancer more than from other causes, but UK respondents do not hold such a premium. We also find that those who face higher baseline risks, due to higher air pollution levels where they live, hold a higher VSL, especially in the UK. In both countries, the VSL is twice as large among individuals who perceive air pollution where they live as relatively high.

EComment. Postoperative delirium in cardiac surgery

Palmbergen et al. [1] are to be commended for evaluating a novel strategy called the Haga Brain Care Strategy, to reduce the incidence of postoperative delirium in patient undergoing cardiac surgery. The implementation of the Haga Brain Care Strategy yielded a significant reducing in the incidence of postoperative delirium (from 13.3% to 7.3%). This simple strategy consisted of the conventional screening protocol for delirium with the addition of preoperative transcranial Doppler examinations, perioperative cerebral oximetry, modified Rankin score and delirium risk score. Delirium, or acute confusion, is a transient neurologic complication characterized by disturbances in consciousness, perception and cognition [2]. Delirium is a common and increasingly prevalent mental syndrome after cardiac surgery, and may be associated with increased morbidity and mortality. Delirium after cardiac surgery is also associated with many negative early consequences such as prolonged hospital and intensive care stay, increased rate of infection, higher prevalence of sternum instability, more readmission, more nursing home placement and poorer functional outcomes [3]. Since the syndrome is, by definition, a temporary one, there is a trend to view this mental syndrome as self-limited, and therefore without long-term sequelae. However, recently published investigations [4-5] showed that delirium is not only problematic in the immediate perioperative period, but it is also associated with poorer 1- and 5-year outcomes in patients undergoing cardiac surgery. A study by Martin et al. [4] assessing the 5-year outcomes in 496 delirious patients after cardiac surgery established that patient with delirium appear to have an increased long- term risk of mortality (hazard ratio, 1.52; 95% CI, 1.29-1.78) and hospitalization for stroke (hazard ratio, 1.54; 95% CI, 1.10-2.17). A prospective study by Saczynski et al. [5] enrolling 225 patients undergoing cardiac surgery from three centres and following them for 12 months after surgery showed that patient with postoperative delirium had a significant decline in cognitive ability up to one year after surgery with a long- lasting period of significant impairment. Therefore, prevention of delirium must be enhanced to reduced early- and long-term morbidity. Early recognition of delirium symptoms enables the underlying cause to be diagnosed and treated, and can prevent negative outcomes. This important investigation with convincing data demonstrates that postoperative delirium can be preventable. We completely concur with the authors that proactive interventions are warranted to prevent this temporary mental dysfunction with long-lasting sequelae. Conflict of Interest: None declared

Sensitive cardiac troponin in the diagnosis and risk stratification of acute heart failure

The aim of our study was to investigate the diagnostic and prognostic value of a sensitive cardiac troponin I (s-cTnI) assay in patients with acute heart failure (AHF). Sensitive cardiac troponin I was measured in 667 consecutive patients at presentation to the emergency department with acute dyspnoea. Three s-cTnI strata were predefined: below the limit of detection (<0.01 μg L(-1) , undetectable), detectable but still within the normal range (0.01-0.027 μg L(-1) ) and increased (≥0.028 μg L(-1) , ≥99th percentile). The final diagnosis was adjudicated by two independent cardiologists blinded to the s-cTnI levels. Median follow-up in patients with AHF was 371 days. Levels of s-cTnI were higher in patients with AHF (n = 377, 57%) compared to patients with noncardiac causes of acute dyspnoea (median 0.02 vs. <0.01 μg L(-1) , P < 0.001). In patients with AHF, in-hospital mortality increased with increasing s-cTnI in the three strata (2%, 5% and 14%, P < 0.001). One-year mortality also increased with increasing s-cTnI (21%, 33% and 47%, P < 0.001). s-cTnI remained an independent predictor of 1-year mortality [adjusted odds ratio 1.03 for each increase of 0.1 μg L(-1) , 95% confidence interval (CI) 1.02-1.05, P < 0.001] after adjustment for other risk factors including B-type natriuretic peptide. The net reclassification improvement was 68% (P < 0.001), and absolute integrated discrimination improvement was 0.18 (P < 0.001). The diagnostic accuracy of s-cTnI for the diagnosis of AHF as quantified by the area under the receiver operating characteristic curve was 0.78 (95% CI, 0.75-0.82). Sensitive cardiac troponin I is a strong predictor of short- and long-term prognosis in AHF that helps to reclassify patients in terms of mortality risk. Detectable levels of s-cTnI, even within the normal range, are independently associated with mortality.

Fitness trade‐offs associated with oviposition strategy in the winter cherry bug, Acanthocoris sordidus

AbstractIn phytophagous insects, oviposition strategy is determined by complex trade‐offs among many factors. The winter cherry bug, Acanthocoris sordidus Thunberg (Heteroptera: Coreidae), deposits its eggs not only on host plants, but also on non‐host plants. Oviposition on non‐host plants may cause higher nymph mortality, as nymphs may be unable to find their host plants during the second instar when the first feeding occurs. Therefore, we hypothesised that this uncommon oviposition strategy would be maintained by a trade‐off between egg and nymphal mortality risks. To test this hypothesis, we conducted field surveys to compare egg mortality due to biotic (predation and parasitism) and abiotic factors on host plants vs. non‐host plants. We also conducted a semi‐field experiment to quantify the risk of nymphal mortality caused by oviposition on non‐hosts during the second instar. In terms of mortality risk during the egg stage, a 2‐year field survey revealed that oviposition on non‐host plants resulted in higher survival of eggs than on host plants; this strategy was also particularly effective for avoiding attacks by ground‐living arthropod predators. In terms of mortality risk during the nymphal stage, the semi‐field experiment demonstrated that nymphs placed off host plants do risk being unable to reach host plants. However, the presence of conspecific adults on host plants increased the probability that nymphs reached host plants. Therefore, second instars may have evolved the ability to utilise chemical cues emitted by adults on host plants or by host plants fed by adults to reduce their risk of not reaching host plants. We concluded that oviposition on non‐host plants by A. sordidus females could be maintained by the balance between the benefit of lower egg mortality and the cost of higher nymph mortality compared to oviposition on host plants.

Beta-Blocker Prescription Among Japanese Cardiologists and Its Effect on Various Outcomes

Beta-blockers are underprescribed for coronary artery disease (CAD) patients in Japan. Considering the vast amount of evidence showing their benefits in this group of patients, the aim of the present study was to investigate the use of beta-blockers in a large cohort of CAD patients. The 13,812 patients with angiographically confirmed CAD were followed up for 2.7 years. From this group, 4,160 (30.1%) patients were prescribed beta-blockers at the time of discharge. These patients were significantly more likely to have hypertension, hyperlipidemia, obesity, a family history of ischemic diseases and a higher number of diseased arteries. The rate of continuation for beta-blockers was 90.8%. A propensity score matching analysis showed no additional benefits of beta-blockers in reducing all-cause mortality, cardiac events and cerebrovascular events. Lipophilic beta-blockers were significantly more effective than hydrophilic ones in reducing all-cause mortality (hazard ratio 0.467, 95% confidence interval 0.247-0.880, P=0.019). Despite the low prescription rate of beta-blockers for CAD patients among Japanese physicians, the continuation rate was relatively high. Lipophilic beta-blockers may be a better choice than hydrophilic beta-blockers in terms of mortality risk, although a randomized control study would need to be conducted to verify this assertion.

Cystatin C, Albuminuria, and Mortality Among Older Adults With Diabetes

OBJECTIVEAlbuminuria and impaired glomerular filtration rate (GFR) are each associated with poor health outcomes among individuals with diabetes. Joint associations of albuminuria and impaired GFR with mortality have not been comprehensively evaluated in this population.RESEARCH DESIGN AND METHODSThis is a cohort study among Cardiovascular Health Study participants with diabetes, mean age 78 years. GFR was estimated using serum cystatin C and serum creatinine. Albumin-to-creatinine ratio (ACR) was measured in single-voided urine samples.RESULTSOf 691 participants, 378 died over 10 years of follow-up. Cystatin C–estimated GFR <60 ml/min per 1.73 m2, creatinine-based estimated GFR <60 ml/min per 1.73 m2, and urine ACR ≥30 mg/g were each associated with increased mortality risk with hazard ratios of 1.73 (95% CI 1.37–2.18), 1.54 (1.21–1.97), and 1.73 (1.39–2.17), respectively, adjusting for age, sex, race, diabetes duration, hypoglycemic medications, hypertension, BMI, smoking, cholesterol, lipid-lowering medications, prevalent cardiovascular disease (CVD), and prevalent heart failure. Cystatin C–estimated GFR and urine ACR were additive in terms of mortality risk. Cystatin C–estimated GFR predicted mortality more strongly than creatinine-based estimated GFR.CONCLUSIONSAlbuminuria and impaired GFR were independent, additive risk factors for mortality among older adults with diabetes. These findings support current recommendations to regularly assess both albuminuria and GFR in the clinical care of patients with diabetes; a focus on interventions to prevent or treat CVD in the presence of albuminuria, impaired GFR, or both; and further consideration of cystatin C use in clinical care.

Kreatininanstieg – Langfristig steigt Mortalitäts– und Niereninsuffizienzrisiko

Quelle: Newsome BB, Warnock DG, McClellan WM et al. Long–term risk of mortality and end–stage renal disease among the elderly after small increases in serum creatinine level during hospitalization for acute myocardial infarction. Arch Intern Med 2008; 168 (6): 609–616

Evaluation of trauma care by comparing mortality risks and admission policy in a Dutch trauma region

To evaluate the effectiveness of trauma care in the Netherlands compared to UK norms and in terms of mortality risks in three groups of patients. The hypothesis was that there is no difference in risk of hospital death between major trauma patients transferred from another hospital to the trauma centre and patients directly admitted to the trauma centre. Trauma admissions (n=17,023) during the period 2000-2006 in 12 emergency departments were selected from a regional trauma registry database. In the analysis, the dependent variable was death within 30 days of admission. W-Statistics (W(s)) was used to compare outcomes of the total Dutch trauma population and the population admitted to the trauma centre, with norms for England and Wales. The effect of direct admission to a non-trauma centre and immediate admission to a trauma centre for major trauma patients versus indirect admission was tested in a logistic model and adjusted for confounding. 444 (2.6%) patients died within 30 days of admission. 6.1% of all patients were major trauma patients. W(s) resulted in 1.39 (95% CI 1.08-1.70) more observed survivors per 100 admitted trauma patients standardised for case mix using UK norms. W(s) of trauma patients in the trauma centre resulted in 0.85 (95% CI 0.44-1.27) more survivors than expected. Patients directly admitted to a trauma centre or a non-trauma centre without transfer were found to have a non-significant increasing risk of mortality (OR 1.5 (95% CI 0.7-3.4) and 1.9 (95% CI 0.9-4.1), respectively) compared to patients transferred from another hospital to a trauma centre. Trauma care in this Dutch province is performing better than expected comparing to the norms for the England and Wales. The admission policy of transporting major trauma patients to the nearest hospital and, if necessary, then transferring them to the trauma centre, seems legitimate in Dutch trauma care.

Quantifying functional connectivity: experimental assessment of boundary permeability for the natterjack toad (Bufo calamita)

Like other pond-breeding amphibians, the natterjack toad (Bufo calamita) typically presents a patchy distribution. Because the species experiences high probabilities of local population extinction, its persistence within landscapes relies on both local and landscape-scale processes [dispersal allowing the (re)colonization of habitat patches]. However, the structure and composition of the matrix surrounding local populations can alter the dispersal rates between populations. As shown previously (Landscape Ecol 19:829-842, 2004), the locomotor performances of individuals at the dispersal stage depend on the nature of the component crossed: some landscape components offer high resistance to movement (high resistance or high viscosity components) whereas others allow high efficiency of movement (low resistance components). We now examine the ability of individuals to discriminate between landscape components and select low-resistance components. Our experimental study investigates the ways in which young natterjack toads choose from among landscape components common to southern Belgium. Toadlets (the dispersal stage) were experimentally confronted with boundaries between surrogates of sandy soils, roads, forests, agricultural fields and intensive pastures. Our results show: 1 the ability of toadlets to react to boundaries between landscape components, 2 differences in permeability among boundaries, and 3 our inability to predict correctly the permeability of the boundaries from the patch-specific resistance assessed previously. Toadlets showed a preference for bare environments and forests, whereas they avoided the use of agricultural environments. This pattern could not be explained in terms of patch-specific resistance only, and is discussed in terms of mortality risks and resource availability in the various landscape components, with particular attention to repercussions on conservation strategies.

A review of environmental hazards associated with in-patient falls

Slips, trips and falls present the greatest risk to in-patients in terms of exposure (frequency of occurrence) but only present a low severity risk in terms of mortality. The risk factors have been categorized as intrinsic (individual to the patient, e.g. visual impairment, balance problems and medicine use) or extrinsic (environmental). Many recommendations have been made concerning the management of environmental hazards but, of these, only beds rails have supporting research evidence. Other recommendations include patient assessment, footwear, flooring, lighting, staffing levels and bed alarms. However, three systematic reviews and the current narrative review have all failed to find research evaluating the benefits of these recommendations. The most robust evidence relates to the use of bed rails. This research suggests that bed rails not only fail to reduce the frequency of falls, but may also exacerbate the severity of injury. As Maslow's Hierarchy of Needs model has been used as a framework for nursing models of care, it was chosen as the basis for the development of an environmental hazard assessment model. The environmental hazards are revisited using this model in order to take an ergonomic or patient-centred approach for risk assessment.

Counting the costs of overweight and obesity: modeling clinical and cost outcomes

ABSTRACTObjective: To quantify changes in clinical and cost outcomes associated with increasing levels of body mass index (BMI) in a US setting.Research methods and procedures: A semi-Markov model was developed to project and compare life expectancy (LE), quality-adjusted life expectancy (QALE) and direct medical costs associated with distinct levels of BMI in simulated adult cohorts over a lifetime horizon. Cohort definitions included age (20–65 years), gender, race, and BMI (24–45 kg m−2). Cohorts were exclusively male or female and either Caucasian or African-American. Mortality rates were adjusted according to these factors using published data. BMI progression over time was modeled. BMI-dependent US direct medical costs were derived from published sources and inflated to year 2004 values. A third party reimbursement perspective was taken. QALE and costs were discounted at 3% per annum.Results: In young Caucasian cohorts LE decreased as BMI increased. However, in older Caucasian cohorts the BMI associated with greatest longevity was higher than 25 kg m−2. A similar pattern was observed in young adult African-American cohorts. A survival paradox was projected in older African-American cohorts, with some BMI levels in the obese category associated with greatest longevity. QALE in all four race/gender cohorts followed similar patterns to LE. Sensitivity analyses demonstrated that simulating BMI progression over time had an important impact on results. Direct costs in all four cohorts increased with BMI, with a few exceptions.Conclusions: Optimal BMI, in terms of longevity, varied between race/gender cohorts and within these cohorts, according to age, contributing to the debate over what BMI level or distribution should be considered ideal in terms of mortality risk. Simulating BMI progression over time had a substantial impact on health outcomes and should be modeled in future health economic analyses of overweight and obesity.

Analysis of air pollution mortality in terms of life expectancy changes: relation between time series, intervention, and cohort studies.

BackgroundInformation on life expectancy change is of great concern for policy makers, as evidenced by the discussions of the so-called "harvesting" issue (i.e. the question being, how large a loss each death corresponds to in the mortality results of time series studies).MethodsWhereas most epidemiological studies of air pollution mortality have been formulated in terms of mortality risk, this paper shows that a formulation in terms of life expectancy change is mathematically equivalent, but offers several advantages: it automatically takes into account the constraint that everybody dies exactly once, regardless of pollution; it provides a unified framework for time series, intervention studies and cohort studies; and in time series and intervention studies, it yields the life expectancy change directly as a time integral of the observed mortality rate.ResultsResults are presented for life expectancy change in time series studies. Determination of the corresponding total number of attributable deaths (as opposed to the number of observed deaths) is shown to be problematic. The time variation of mortality after a change in exposure is shown to depend on the processes by which the body can repair air pollution damage, in particular on their time constants. Hypothetical results are presented for repair models that are plausible in view of the available intervention studies of air pollution and of smoking cessation. If these repair models can also be assumed for acute effects, the results of cohort studies are compatible with those of time series.ConclusionThe proposed life expectancy framework provides information on the life expectancy change in time series studies, and it clarifies the relation between the results of time series, intervention, and cohort studies.

Gender and mortality risk on the waiting list for coronary artery bypass grafting.

There are gender differences in clinical presentation, treatment and outcome of patients with coronary artery disease. We investigated whether there is also a gender difference in terms of mortality risk on the waiting list in patients accepted for coronary artery bypass grafting (CABG). All our patients accepted for elective CABG 1995-1999 (1303 women and 4561 men) were included. Prospectively registered preoperative characteristics and mortality were compared between men and women. Hazard functions for death on the waiting list were calculated using Poisson regression. At acceptance, women were older (68+/-9 vs 65+/-9 years, P<0.001), had a higher Cleveland risk score (2.4+/-1.8 vs 1.8+/-1.8, P<0.001) and a better left ventricular ejection fraction (60+/-14 vs 57+/-14%, P<0.001). More women had unstable angina pectoris (33 vs 20%, P<0.001), diabetes mellitus (23 vs 17%, P<0.001), chronic obstructive pulmonary disease (8 vs 5%, P<0.001), hypertension (47 vs 37%, P<0.001) and planned concomitant aortic valve surgery (13 vs 4%, P<0.001) while more men had three vessel disease (70 vs 66%, P=0.001). Median waiting time (55 vs 54 days, P=0.19) and unadjusted mortality (1.4 vs 1.0%, P=0.25) on the waiting list did not differ significantly between men and women but in a multivariate hazard analysis, female gender was associated with a lower risk than men of death on the waiting list (risk ratio 0.42, 95% confidence interval 0.19-0.93, P=0.032). Women have a lower risk of death on the waiting list for CABG, in spite of more advanced age, more co-morbidity, and a higher percentage of unstable angina pectoris.