***TASK*** the task is to summarize an input biomedical literature in six sentences 
    ***INPUT*** the input is a biomedical literature 
    ***OUTPUT*** the output is the summary of an input biomedical literature in six sentences 
    ***DOCUMENTATION*** 
    ***EXAMPLES*** 
    Input: BACKGROUND The incidence of congestive heart failure ( CHF ) has been increasing steadily in the United States during the past 2 decades . We studied risk factors for CHF and their corresponding attributable risk in the First National Health and Nutrition Examination Survey Epidemiologic Follow-up Study . PARTICIPANTS AND METHODS A total of 13 643 men and women without a history of CHF at baseline examination were included in this prospect i ve cohort study . Risk factors were measured using st and ard methods between 1971 and 1975 . Incidence of CHF was assessed using medical records and death certificates obtained between 1982 and 1984 and in 1986 , 1987 , and 1992 . RESULTS During average follow-up of 19 years , 1382 CHF cases were documented . Incidence of CHF was positively and significantly associated with male sex ( relative risk [ RR ] , 1.24 ; 95 % confidence interval [ CI ] , 1.10 - 1.39 ; P<.001 ; population attributable risk [ PAR ] , 8.9 % ) , less than a high school education ( RR , 1.22 ; 95 % CI , 1.04 - 1.42 ; P = .01 ; PAR , 8.9 % ) , low physical activity ( RR , 1.23 ; 95 % CI , 1.09 - 1.38 ; P<.001 ; PAR , 9.2 % ) , cigarette smoking ( RR , 1.59 ; 95 % CI , 1.39 - 1.83 ; P<.001 ; PAR , 17.1 % ) , overweight ( RR , 1.30 ; 95 % CI , 1.12 - 1.52 ; P = .001 ; PAR , 8.0 % ) , hypertension ( RR , 1.40 ; 95 % CI , 1.24 - 1.59 ; P<.001 ; PAR , 10.1 % ) , diabetes ( RR , 1.85 ; 95 % CI , 1.51 - 2.28 ; P<.001 ; PAR , 3.1 % ) , valvular heart disease ( RR , 1.46 ; 95 % CI , 1.17 - 1.82 ; P = .001 ; PAR , 2.2 % ) , and coronary heart disease ( RR , 8.11 ; 95 % CI , 6.95 - 9.46 ; P<.001 ; PAR , 61.6 % ) . CONCLUSIONS Male sex , less education , physical inactivity , cigarette smoking , overweight , diabetes , hypertension , valvular heart disease , and coronary heart disease are all independent risk factors for CHF . More than 60 % of the CHF that occurs in the US general population might be attributable to coronary heart disease OBJECTIVES The goal of this study was to determine the influence of gender on baseline characteristics , response to treatment , and prognosis in patients with heart failure ( HF ) and impaired left ventricular ejection fraction ( LVEF ) . BACKGROUND Under-representation of women in HF clinical trials has limited our underst and ing of gender-related differences in patients with HF . METHODS The impact of gender was assessed in the Beta-Blocker Evaluation of Survival Trial ( BEST ) which r and omized 2,708 patients with New York Heart Association class III/IV and LVEF < or = 0.35 to bucindolol versus placebo . Women ( n = 593 ) were compared with men ( n = 2,115 ) . Mean follow-up period was two years . RESULTS Significant differences in baseline clinical and laboratory characteristics were found . Women were younger , more likely to be black , had a higher prevalence of nonischemic etiology , higher right and left ventricular ejection fraction , higher heart rate , greater cardiothoracic ratio , higher prevalence of left bundle branch block , lower prevalence of atrial fibrillation , and lower plasma norepinephrine level . Ischemic etiology and measures of severity of HF were found to be predictors of prognosis in women and men . However , differences in the predictive values of various variables were noted ; most notably , coronary artery disease and LVEF appear to be stronger predictors of prognosis in women . In the nonischemic patients , women had a significantly better survival rate compared with men . CONCLUSIONS In HF patients with impaired LVEF , significant gender differences are present , and the prognostic predictive values of some variables vary in magnitude between women and men . The survival advantage of women is confined to patients with nonischemic etiology STUDY OBJECTIVES To investigate in older patients with congestive heart failure ( CHF ) associated with prior myocardial infa rct ion or hypertension the relationship between normal left ventricular ( LV ) ejection fraction and age , gender , hypertension , prior myocardial infa rct ion , and atrial fibrillation . DESIGN A prospect i ve study was performed in 572 older patients ( age > 60 years ) with CHF associated with prior myocardial infa rct ion or hypertension and technically adequate two-dimensional echocardiograms for measuring LV ejection fraction . SETTING A long-term health-care facility . PATIENTS One hundred seventy-seven men and 395 women , mean age 82+/-8 years , with CHF associated with prior myocardial infa rct ion or hypertension . MEASUREMENTS AND RESULTS Normal LV ejection fraction ( > or = 50 % ) occurred in 66 of 177 men ( 37 % ) and in 221 of 395 women ( 56 % ) ( p<0.0001 ) . Multiple logistic regression analysis showed that independent risk factors for normal LV ejection fraction in patients with CHF were no prior myocardial infa rct ion ( p=0.0001 ; odds ratio=3.048 ) , female gender ( p=0.0004 ; odds ratio=1.978 ) , and age ( p=0.016 ; odds ratio=1.029 ) . CONCLUSIONS Normal LV ejection fraction occurred in 50 % of 572 older patients with CHF associated with prior myocardial infa rct ion or hypertension . Independent risk factors for normal LV ejection fraction in patients with CHF were no prior myocardial infa rct ion , female gender , and age OBJECTIVES To determine the prevalence of diastolic heart failure in older people in the community , identify associated risk factors and measure its impact on function and quality of life . DESIGN Cross-sectional population -based study . METHODS A two-stage r and om sample of 500 subjects was drawn from 5,002 subjects aged 70 years and over living at home . Diastolic heart failure was diagnosed by a panel of three physicians , based on clinical assessment and echocardiographic indicators of diastolic dysfunction . MAIN OUTCOME MEASURES Prevalence of diastolic heart failure and its effect on function and quality of life as measured by  Nottingham Extended Activities of Daily Living , Hospital Anxiety and Depression and SF-36 question  naires . RESULTS The prevalence of diastolic heart failure was 5.54 % ( 95 % CI = 3.71 , 7.87 ) and was higher in women ( 8.32 % ) than in men ( 1.25 % ) , P = 0.008 . On multivariate analysis of variance , diastolic heart failure was associated with female gender and history of ischaemic heart disease . Subjects with diastolic heart failure had significantly poorer functional status and physical health than those without heart failure . CONCLUSIONS Diastolic heart failure is relatively common in older people and is associated with adverse affects in older people 's lives OBJECTIVE To estimate the prevalence of heart failure ( HF ) and left ventricular ( LV ) systolic dysfunction in a population -based sample of older Australians . DESIGN , SETTING AND PARTICIPANTS A cross-sectional survey of 2000 r and omly selected residents of Canberra , aged 60 - 86 years , conducted between February 2002 and June 2003 . Participants were assessed by history , physical examination by a cardiologist , and echocardiography . MAIN OUTCOME MEASURES Age- and sex-specific prevalence rates of clinical HF and LV systolic dysfunction ( defined as LV ejection fraction < or = 50 % ) . RESULTS Of 1846 people eligible for our study , 1388 ( 75 % ) agreed to participate and 1275 completed all investigations ( mean age , 69.4 years ; 50 % men ) . In the study sample , 72 subjects ( 5.6 % ; 95 % CI , 4.4%-7.1 % ) had clinical HF that had been previously diagnosed and was confirmed by our assessment . A further 0.6 % ( 95 % CI , 0.3%-1.2 % ) had undiagnosed clinical HF ( ie , evidence of structural heart disease and symptoms/signs of cardiac insufficiency without a previous diagnosis of clinical HF ) . Thus , the overall prevalence of clinical HF in the sample was 6.3 % ( 95 % CI , 5.0%-7.7 % ) . Clinical HF increased in prevalence with advancing age ( a 4.4-fold increase from the 60 - 64-years age group to the 80 - 86-years age group ; P < 0.0001 ) . Of the 75 subjects ( 5.9 % ; 95 % CI , 4.7%-7.3 % ) with LV systolic dysfunction , 44 ( 59 % ) were in the pre clinical stage of disease . CONCLUSION Diagnosed HF cases represent the " tip of the iceberg " for the national burden of HF and LV systolic dysfunction . Clinical ly identifiable HF cases can remain undiagnosed , and the majority of people with LV systolic dysfunction are in a pre clinical stage of the disease OBJECTIVES We sought to characterize the predictors of incident congestive heart failure ( CHF ) , as determined by central adjudication , in a community-based elderly population . BACKGROUND The elderly constitute a growing proportion of patients admitted to the hospital with CHF , and CHF is a leading source of morbidity and mortality in this group . Elderly patients differ from younger individuals diagnosed with CHF in terms of biologic characteristics . METHODS We analyzed data from the Cardiovascular Health Study , a prospect i ve population -based study of 5,888 elderly people > 65 years old ( average 73 + /- 5 , range 65 to 100 ) at four locations . Multiple laboratory measures of cardiovascular structure and function , blood chemistries and functional assessment s were obtained . RESULTS During an average follow-up of 5.5 years ( median 6.3 ) , 597 participants developed incident CHF ( rate 19.3/1,000 person-years ) . The incidence of CHF increased progressively across age groups and was greater in men than in women . On multivariate analysis , other independent predictors included prevalent coronary heart disease , stroke or transient ischemic attack at baseline , diabetes , systolic blood pressure ( BP ) , forced expiratory volume 1 s , creatinine > 1.4 mg/dl , C-reactive protein , ankle-arm index < 0.9 , atrial fibrillation , electrocardiographic ( ECG ) left ventricular ( LV ) mass , ECG ST-T segment abnormality , internal carotid artery wall thickness and decreased LV systolic function . Population -attributable risk , determined from predictors of risk and prevalence , was relatively high for prevalent coronary heart disease ( 13.1 % ) , systolic BP > or = 140 mm Hg ( 12.8 % ) and a high level of C-reactive protein ( 9.7 % ) , but was low for subnormal LV function ( 4.1 % ) and atrial fibrillation ( 2.2 % ) . CONCLUSIONS The incidence of CHF is high in the elderly and is related mainly to age , gender , clinical and sub clinical coronary heart disease , systolic BP and inflammation . Despite the high relative risk of subnormal systolic LV function and atrial fibrillation , the actual population risk of these for CHF is small because of their relatively low prevalence in community-dwelling elderly people Congestive heart failure ( CHF ) is the leading cause of hospitalization in the elderly , and these patients are at high risk for subsequent hospitalization . Whether gender affects the risk of rehospitalization in patients who have CHF is less well understood . We studied a r and om sample of 1,700 adults who had been hospitalized with CHF ( from July 1 , 1999 to June 30 , 2000 ) and identified all readmissions through June 30 , 2001 . We used proportional hazards regression to evaluate whether gender affects the risk of all-cause and CHF-specific rehospitalization , after adjusting for differences in demographic characteristics , health-related behaviors , co-morbid conditions , left ventricular systolic function status , and use of CHF therapies . Among 1,591 adults who had confirmed CHF , 752 were women ( 47.3 % ) . Women were older than men ( 73 vs 71 years , p < 0.001 ) and more likely to have preserved systolic function ( 55 
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RESULTS Ventricular systolic dysfunction being more associated with male sex , but female sex was more reported to be associated with preserved left ventricular function .
Ischemic etiology and associated coronary heart disease were strongly correlated with male sex .
The risk for HF was dramatically more elevated for women with systolic hypertension but the association for diabetes mellitus as the etiology of HF was somewhat equal between males and females .