***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 Recent reports have drawn attention to the importance of pulse pressure as a predictor of cardiovascular events .  Pulse pressure is used neither by clinicians nor by guidelines to define treatable levels of blood pressure . METHODS In the Cardiovascular Health Study , 5888 adults 65 years and older were recruited from 4 US centers . At baseline in 1989 - 1990 , participants underwent an extensive examination , and all subsequent cardiovascular events were ascertained and classified . RESULTS At baseline , 1961 men and 2941 women were at risk for an incident myocardial infa rct ion or stroke . During follow-up that averaged 6.7 years , 572 subjects had a coronary event , 385 had a stroke , and 896 died . After adjustment for potential confounders , systolic blood pressure ( SBP ) , diastolic blood pressure ( DBP ) , and pulse pressure were directly associated with the risk of incident myocardial infa rct ion and stroke . Only SBP was associated with total mortality . Importantly , SBP was a better predictor of cardiovascular events than DBP or pulse pressure . In the adjusted model for myocardial infa rct ion , a 1-SD change in SBP , DBP , and pulse pressure was associated with hazard ratios ( 95 % confidence intervals ) of 1.24 ( 1.15 - 1.35 ) , 1.13 ( 1.04 - 1.22 ) , and 1.21 ( 1.12 - 1.31 ) , respectively ; and adding pulse pressure or DBP to the model did not improve the fit . For stroke , the hazard ratios ( 95 % confidence intervals ) were 1.34 ( 1.21 - 1.47 ) with SBP , 1.29 ( 1.17 - 1.42 ) with DBP , and 1.21 ( 1.10 - 1.34 ) with pulse pressure . The association between blood pressure level and cardiovascular disease risk was generally linear ; specifically , there was no evidence of a J-shaped relationship . In those with treated hypertension , the hazard ratios for the association of SBP with the risks for myocardial infa rct ion and stroke were less pronounced than in those without treated hypertension . CONCLUSION In this population -based study of older adults , although all measures of blood pressure were strongly and directly related to the risk of coronary and cerebrovascular events , SBP was the best single predictor of cardiovascular events Background In patients with cardiovascular disease , a high pulse pressure is related to an increased risk of cardiovascular events but in patients with advanced heart failure , a low pulse pressure is predictive of adverse ( cardiovascular ) events . Aim We studied the prognostic importance of  pulse pressure  in a group of post-myocardial infa rct ion patients , with and without signs and symptoms of heart failure . Subjects had been r and omised in the CAPRICORN clinical trial , and followed up for a mean of 1.3 years . Methods  Blood pressure  was measured in 1,955 patients with a left ventricular ejection fraction ≤40 % , between 3 and 21 days post myocardial infa rct ion . Cox proportional survival models were reproduced for those with Killip Class I ( n = 1342 ) versus classes II/III/IV heart failure ( n = 613 ) . Results Overall mean ( SD ) age was 63 ( 12 ) years , mean ( SD ) left ventricular ejection fraction 33(6)% , mean ( SD ) baseline blood pressure was 121 (17)/74 ( 10 ) mmHg and most ( 73 % ) were male . In patients with Killip Class 1 , pulse pressure was not predictive for any outcome . However , in patients with Killip Class II – IV , a low pulse pressure independently predicted all cause mortality ( HR 0.83 per 10 mmHg , CI 0.71–0.98 , p = 0.025 ) , cardiovascular mortality ( HR 0.83 per 10 mmHg , CI 0.70–0.98 , p = 0.025 ) and sudden death ( HR 0.77 per 10 mmHg , CI 0.60–1.00 , p = 0.047 ) . A lower pulse pressure did not predict hospitalisation for worsening heart failure . Conclusion A low pulse pressure is an independent predictor of mortality in subjects with depressed left ventricular ejection fraction after a recent myocardial infa rct ion and evidence of Killip Class II – IV heart failure Abstract Objective : This study aims to develop and vali date a stroke risk model incorporating pulse pressure ( PP ) as a potential risk factor . Recent evidence suggests that PP , defined as the difference between systolic blood pressure ( SBP ) and diastolic blood pressure ( DBP ) , could be an incremental risk factor beyond SBP . Methods :  Electronic health records ( EHRs ) of hypertensive patients from a US integrated health delivery system were analyzed ( January 2004 to May 2012 ) . Patients with ≥1 PP reading and ≥6 months of observation prior to the first diagnosis of hypertension were r and omly split into development ( two-thirds of sample ) and validation ( one-third of sample ) data sets . Stroke events were identified using ICD-9-CM 433.xx–436.xx . Cox proportional hazards models assessed time to first stroke event within 3 years of first hypertension diagnosis based on baseline risk factors , including PP , age , gender , diabetes , and cardiac comorbidities . The optimal model was selected using the least absolute shrinkage and selection operator ( LASSO ) ; performance was evaluated by the c-statistic . Results : Among 34,797 patients selected ( mean age 59.3 years , 48 % male ) , 4272 patients ( 12.3 % ) had a stroke . PP was higher among patients who developed stroke ( mean [ SD ] PP , stroke : 02.0 [ 15.3 ] mmHg ; non-stroke : 58.1 [ 14.0 ] mmHg , p < 0.001 ) . The best performing risk model ( c-statistic , development : 0.730 ; validation : 0.729 ) included PP ( hazard ratio per mmHg increase : 1.0037 , p < 0.001 ) as a significant risk factor . Limitations : This study was subject to limitations similar to other studies using EHRs . Only patient encounters occurring within the single healthcare network were captured in the data source . Though the model was tested internally , external validation ( using a separate data source ) would help assess the model ’s generalizability and calibration . Conclusions : This stroke risk model shows that greater PP is a significant predictive factor for increased stroke risk , even in the presence of known risk factors . PP should be considered by practitioners along with established risk factors in stroke treatment strategies Objective Although pulse pressure has been recognized a risk factor for coronary heart disease in both middle-aged and elderly , and for stroke in the elderly , the contribution of pulse pressure to the risk of stroke among the middle-aged is uncertain . Methods A total of 33 372 participants ( 11 684 men and 21 688 women aged 40–69 years ) living in communities , free of prior diagnosis of cardiovascular disease and cancer , completed health check-up examination .  They were followed from 1990–1992 to the end of 2004 in the Japan public health center-based prospect i ve study on cancer and cardiovascular disease . After 422 864 person-years of follow-up , 1081 incident strokes ( 559 men and 522 women ) were documented . Results Pulse pressure was positively associated with risk of stroke as was systolic and diastolic blood pressures . The multivariable hazard ratio of total stroke associated with a 1-SD increment ( 13.2 mmHg ) of pulse pressure was 1.14 ( 1.05–1.24 ) . The excess risk was observed for the stratum of systolic blood pressure below 140 mmHg , but not of higher systolic blood pressure levels after adjustment for diastolic blood pressure and other potential confounding factors ; the multivariable hazard ratio of stroke associated with a 1-SD increment of pulse pressure was 1.32 ( 1.07–1.64 ) among persons with normal systolic blood pressure levels . Conclusions Pulse pressure is a risk factor for stroke among normotensive individuals with systolic blood pressure below 140 mmHg , which suggests that pulse pressure may be useful to predict the risk of stroke among middle-aged nonsystolic hypertensive patients Objective : To evaluate which blood pressure measure is the best predictor of risk of total , ischemic , and hemorrhagic stroke . Methods : The authors used a prospect i ve cohort study among 11,466 men followed for incident stroke during a median of 19.4 years in the Physicians ' Health Study .  Systolic blood pressure ( SBP ) and diastolic blood pressure ( DBP )  were self-reported . They calculated relative risks ( RRs ) and 95 % CIs for total , ischemic , and hemorrhagic stroke using Cox proportional hazards models . Model fit was compared using the χ2 test statistic from likelihood ratio tests . Results : During follow-up , 508 strokes occurred ( 411 ischemic , 89 hemorrhagic , and eight of unknown etiology ) . For each 10-mm Hg increase in SBP , the multivariable RRs were 1.31 ( 95 % CI : 1.20 to 1.42 ) for total stroke , 1.28 ( 95 % CI : 1.16 to 1.40 ) for ischemic stroke , and 1.38 ( 95 % CI : 1.13 to 1.68 ) for hemorrhagic stroke . Although DBP , pulse pressure , and mean arterial pressure were all significant predictors of stroke risk , none was a significantly better predictor than SBP alone . Adding DBP did not significantly improve the model fit of SBP alone for any stroke type . Conclusion : In this large cohort of initially healthy men  , systolic blood pressure was a consistent and significant predictor of total , ischemic , and hemorrhagic stroke . Systolic blood pressure alone was the only measure necessary to predict risk of total stroke or its major subtypes Background and Purpose — The purpose of this prospect i ve cohort study was to investigate associations between stroke and blood pressure ( BP ) indices ( systolic BP [ SBP ] , diastolic BP [ DBP ] , mean BP , and pulse pressure [ PP ] ) determined by home BP measurement . Methods — Associations between stroke and BP indices were examined in a rural Japanese population . Home BP data  of 2369 subjects ( 40 % men ) ≥35 years of age ( mean , 59 years ) without a history of stroke were obtained . Associations between stroke and each index were determined using Cox proportional hazards regression and the likelihood ratio ( LR ) test . Results — During follow-up ( mean , 11.7 years ) , 238 strokes occurred . The LR test showed that SBP and mean BP were significantly more strongly associated with total and ischemic stroke than DBP and PP ( LR & khgr;2 ≥9.3 , P<0.01 for SBP/mean BP , LR & khgr;2 ≤3.8 , P≥0.05 for DBP/PP ) . SBP tended to be more strongly associated with total/ischemic stroke than mean BP ( LR & khgr;2=3.8 , P=0.05 for SBP , LR & khgr;2 ≤0.2 , P>0.6 for mean BP ) . PP tended to be slightly more strongly associated with ischemic stroke than DBP ( LR & khgr;2=7.5 , P<0.01 for DBP , LR & khgr;2=9.3 , P<0.01 for PP ) , whereas DBP was significantly more strongly associated with hemorrhagic stroke than PP ( LR & khgr;2=9.2 , P<0.01 for DBP , LR & khgr;2=2.5 , P=0.01 for PP ) . Conclusion — PP obtained from home BP measurements was weakly associated with stroke , whereas SBP showed the strongest association . Additionally , DBP and PP may be associated with different stroke types Background Our objective was to test the hypothesis that elevated blood pressure ( BP ) is associated with increased risk of stroke , bleeding and death in patients with incident heart failure ( HF ) . Methods We conducted a prospect i ve cohort study among subjects who were participants in the Diet , Cancer and Health study , born in Denmark , aged 50–64 years at recruitment . We assessed stroke ( ischemic stroke or systemic embolic events ) , major bleeding , death and the composite endpoint according to degree of BP control in patients with incident HF .  BP  was assessed prior to HF at cohort entry . Results Of the whole cohort of 55,748 subjects , n = 2159 ( 35 % female ) had incident HF , of which 12 % had treatment for hypertension . Median follow-up after incident HF was 3.5 years . High systolic ( SBP ) , diastolic ( DBP ) and pulse ( PP ) pressures were associated with an increased risk of stroke , major bleeding and the composite endpoint . For death and stroke/death , the relation appeared U-shaped for SBP and DBP . When comparing the highest quartile group ( Q4 ) to first quartile group ( Q1 ) , SBP ( Q4 : SBP > 163 mmHg ) was 
    Output:
    
Conclusions Current data confirms that PP is an independent risk factor for stroke but is not a predictor of mortality