***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: CONTEXT The clinical use of ambulatory blood pressure ( BP ) monitoring requires further validation in prospect i ve outcome studies . OBJECTIVE To compare the prognostic significance of conventional and ambulatory BP measurement in older patients with isolated systolic hypertension . DESIGN Sub study to the double-blind placebo-controlled Systolic Hypertension in Europe ( Syst-Eur ) Trial , started in October 1988 with follow up to February 1999 . The conventional BP at r and omization was the mean of 6 readings ( 2 measurements in the sitting position at 3 visits 1 month apart ) . The baseline ambulatory BP was recorded with a noninvasive intermittent technique . SETTING Family practice s and outpatient clinics at primary and secondary referral hospitals . PARTICIPANTS A total of 808 older ( aged > or = 60 years ) patients whose untreated BP level on conventional measurement at baseline was 160 to 219 mm Hg systolic and less than 95 mm Hg diastolic . INTERVENTIONS For the overall study , patients were r and omized to nitrendipine ( n = 415 ; 10 - 40 mg/d ) with the possible addition of enalapril ( 5 - 20 mg/d ) and /or hydrochlorothiazide ( 12.5 - 25.0 mg/d ) or to matching placebos ( n = 393 ) . MAIN OUTCOME MEASURES Total and cardiovascular mortality , all cardiovascular end points , fatal and nonfatal stroke , and fatal and nonfatal cardiac end points . RESULTS After adjusting for sex , age , previous cardiovascular complications , smoking , and residence in western Europe , a 10-mm Hg higher conventional systolic BP at r and omization was not associated with a worse prognosis , whereas in the placebo group , a 10-mm Hg higher 24-hour BP was associated with an increased relative hazard rate ( HR ) of most outcome measures ( eg , HR , 1.23 [ 95 % confidence interval [ CI ] , 1.00 - 1.50 ] for total mortality and 1.34 [ 95 % CI , 1.03 - 1.75 ] for cardiovascular mortality ) . In the placebo group , the nighttime systolic BP ( 12 AM-6 AM ) more accurately predicted end points than the daytime level . Cardiovascular risk increased with a higher night-to-day ratio of systolic BP independent of the 24-hour BP ( 10 % increase in night-to-day ratio ; HR for all cardiovascular end points , 1.41 ; 95 % CI , 1.03 - 1.94 ) . At r and omization , the cardiovascular risk conferred by a conventional systolic BP of 160 mm Hg was similar to that associated with a 24-hour daytime or nighttime systolic BP of 142 mm Hg ( 95 % CI , 128 - 156 mm Hg ) , 145 mm Hg ( 95 % CI , 126 - 164 mm Hg ) or 132 mm Hg ( 95 % CI , 120 - 145 mm Hg ) , respectively . In the active treatment group , systolic BP at r and omization did not significantly predict cardiovascular risk , regardless of the technique of BP measurement . CONCLUSIONS In untreated older patients with isolated systolic hypertension , ambulatory systolic BP was a significant predictor of cardiovascular risk over and above conventional BP Background —The prevalence and clinical significance of isolated office ( or white coat ) hypertension is controversial , and population data are limited . We studied the prevalence of this condition and its association with echocardiographic left ventricular mass in the general population of the PAMELA ( Pressione Arteriose Monitorate E Loro Associazioni ) Study . Methods and Results —The study involved a large , r and omized sample ( n=3200 ) representative of the Monza ( Milan ) population , 25 to 74 years of age . Participants in the study ( 64 % of the sample ) underwent measurements of office , home , 24-hour ambulatory blood pressure , and echocardiography . Isolated office hypertension was defined as systolic or diastolic values ≥140 mm Hg or ≥90 mm Hg , respectively . Home and ambulatory normotension were defined according to criteria previously established from the PAMELA Study , for example , < 132/83 mm Hg ( systolic/diastolic ) for home and 125/79 mm Hg for 24-hour average blood pressure . Treated hypertensive subjects were excluded from analysis that was made on a total of 1637 subjects . Depending on normotension being established on systolic or diastolic blood pressure measured at home or over 24 hours , the prevalence of isolated office hypertension ranged from 9 % to 12 % . In these subjects , left ventricular mass index was greater ( P < 0.01 ) than in subjects with normotension both in and outside the office . This was the case also for prevalence of left ventricular hypertrophy . Left ventricular mass index and hypertrophy were similarly greater in subjects found to have normal office but elevated home or ambulatory blood pressure ( ≈10 % of the population ) . Conclusions —Isolated office hypertension has a noticeable prevalence in the population and is accompanied by structural cardiac alterations , suggesting that it is not an entirely harmless phenomenon . This is the case also for the opposite condition , that is , normal office but elevated home or ambulatory blood pressure , which implies that limiting blood pressure measurements to office values may not suffice in identification of subjects at risk Objective To develop and vali date version two of the QRISK cardiovascular disease risk algorithm ( QRISK2 ) to provide accurate estimates of cardiovascular risk in patients from different ethnic groups in Engl and and Wales and to compare its performance with the modified version of Framingham score recommended by the National Institute for Health and Clinical Excellence ( NICE ) . Design Prospect i ve open cohort study with routinely collected data from general practice , 1 January 1993 to 31 March 2008 . Setting 531 practice s in Engl and and Wales contributing to the national Q RESEARCH data base . Participants 2.3 million patients aged 35 - 74 ( over 16 million person years ) with 140 000 cardiovascular events . Overall population ( derivation and validation cohorts ) comprised 2.22 million people who were white or whose ethnic group was not recorded , 22 013 south Asian , 11 595 black African , 10 402 black Caribbean , and 19 792 from Chinese or other Asian or other ethnic groups . Main outcome measures First ( incident ) diagnosis of cardiovascular disease ( coronary heart disease , stroke , and transient ischaemic attack ) recorded in general practice records or linked Office for National Statistics death certificates . Risk factors included self assigned ethnicity , age , sex , smoking status , systolic blood pressure , ratio of total serum cholesterol : high density lipoprotein cholesterol , body mass index , family history of coronary heart disease in first degree relative under 60 years , Townsend deprivation score , treated hypertension , type 2 diabetes , renal disease , atrial fibrillation , and rheumatoid arthritis . Results The validation statistics indicated that QRISK2 had improved discrimination and calibration compared with the modified Framingham score . The QRISK2 algorithm explained 43 % of the variation in women and 38 % in men compared with 39 % and 35 % , respectively , by the modified Framingham score . Of the 112 156 patients classified as high risk ( that is , ≥20 % risk over 10 years ) by the modified Framingham score , 46 094 ( 41.1 % ) would be reclassified at low risk with QRISK2 . The 10 year observed risk among these reclassified patients was 16.6 % ( 95 % confidence interval 16.1 % to 17.0%)—that is , below the 20 % treatment threshold . Of the 78 024 patients classified at high risk on QRISK2 , 11 962 ( 15.3 % ) would be reclassified at low risk by the modified Framingham score . The 10 year observed risk among these patients was 23.3 % ( 22.2 % to 24.4%)—that is , above the 20 % threshold . In the validation cohort , the annual incidence rate of cardiovascular events among those with a QRISK2 score of ≥20 % was 30.6 per 1000 person years ( 29.8 to 31.5 ) for women and 32.5 per 1000 person years ( 31.9 to 33.1 ) for men . The corresponding figures for the modified Framingham equation were 25.7 per 1000 person years ( 25.0 to 26.3 ) for women and 26.4 ( 26.0 to 26.8 ) for men ) . At the 20 % threshold , the population identified by QRISK2 was at higher risk of a CV event than the population identified by the Framingham score . Conclusions Incorporating ethnicity , deprivation , and other clinical conditions into the QRISK2 algorithm for risk of cardiovascular disease improves the accuracy of identification of those at high risk in a nationally representative population . At the 20 % threshold , QRISK2 is likely to be a more efficient and equitable tool for treatment decisions for the primary prevention of cardiovascular disease . As the validation was performed in a similar population to the population from which the algorithm was derived , it potentially has a “ home advantage . ” Further validation in other population s is therefore advised OBJECTIVE : To investigate the risks of high and low blood pressure levels determined by ambulatory blood pressure monitoring and home blood pressure measurements . METHODS : A long-term prospect i ve study of all-cause mortality and cardiovascular mortality has been conducted in Ohasama , Japan since 1987 . RESULTS : The Cox proportional hazards model after adjusting for age and sex demonstrated that , during a 5-year follow-up period involving 893 of the subjects aged 50 years or more in this cohort , those with the lowest quintile of ambulatory blood pressure levels exhibited a significantly higher hazard ratio for cardiovascular and for all-cause mortality . During the same follow-up period , of 1226 subjects aged 50 years and more , those with the lowest and highest quintiles of home blood pressure levels demonstrated a significantly higher hazard ratio with respect to cardiovascular and all-cause mortality ( i.e. , a J-shaped relationship ) . CONCLUSION : These results suggest that there is a significant risk associated with low blood pressure levels , which can be determined by ambulatory and home blood pressure measurements , but not by casual blood pressure measurements BACKGROUND In cross-sectional studies , ambulatory blood pressure  ( ABP ) correlates more closely than clinic BP with the organ damage of hypertension . Whether ABP predicts development or regression of organ damage over time better than clinic BP , however , is unknown . METHODS AND RESULTS In 206 essential hypertensive subjects with left ventricular hypertrophy ( LVH ) , we measured  clinic supine BP , 24-hour ABP  , and left ventricular mass index ( LVMI , echocardiography ) before and after 12 months of treatment with lisinopril ( 20 mg UID ) without or with hydrochlorothiazide ( 12.5 or 25 mg UID ) . Measurements included r and om-zero , clinic orthostatic , and home BP .  In all , 184 subjects completed the 12-month treatment period . Before treatment , clinic supine BP was 165 + /- 15/105 + /- 5 mm Hg ( systolic/diastolic ) , 24-hour average BP was 149 + /- 16/95 + /- 11 mm Hg , and LVMI was 158 + /- 32 g/m2 . At the end of treatment , they were 139 + /- 12/87 + /- 7 mm Hg , 131 + /- 12/83 + /- 10 mm Hg , and 133 + /- 26 g/m2 , respectively ( P < .01 for all ) . Before treatment , LVMI did not correlate with clinic BP , but it showed a correlation with systolic and diastolic 24-hour average BP ( r = .34/.27 , P < .01 ) . The LVMI reduction was not related to the reduction in clinic BP , but it was related to the reduction in 24-hour average BP ( r = .42/.38 , P < .01 ) . Treatment-induced changes in average daytime and nighttime BPs correlated with LVMI changes as strongly as 24-hour BP changes . No substantial advantage over clinic supine BP was shown by clinic orthostatic , r and om-zero , and home BP . CONCLUSIONS In hypertensive subjects with LVH , regression of LVH was predicted much more closely by treatment-induced changes in ABP than in the clinic BP . This provides the first longitudinally controlled evidence that ABP may be clinical ly superior to traditional BP measurements Objective To determine ambulatory and home blood pressure means and distributions in relation to clinic blood pressure in a general population . Methods We obtained a r and om sample of 2400 subjects stratified by sex and 10 year age groups to be representative of residents aged 25–64 years of the city of 
    Output:
    
There are a number of common patient characteristics that predict the home-clinic BP difference , in particular for people with masked hypertension .