***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 
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    Input: PURPOSE We assessed the feasibility of a large r and omized trial intended to determine whether low-dose heparin prophylaxis given throughout hospitalization reduces mortality and morbidity in general medical patients . SUBJECTS AND METHODS Hospitalized general medical patients aged more than 60 years at 5 Department of Veterans Affairs ( VA ) medical centers were r and omized to receive enoxaparin 40 mg or identical placebo , given daily by subcutaneous injection until hospital discharge . Outcomes included total mortality at 90 days ( the primary outcome ) and 1 year , and occurrence in the VA hospital within 90 days of symptomatic deep venous thrombosis , pulmonary embolism , and major bleeding . RESULTS Only 7.6 % of hospitalized patients aged more than 60 years were eligible for the study , although a chart review had predicted 25 % . The principal exclusions were prior indication for anticoagulation , anticipated need for anticoagulation , contraindication to heparin , expected hospitalization less than 3 days , and " supportive/palliative care only " status . We r and omized 140 patients into each group , 28 % of target recruitment . The groups were well matched by age and comorbidities . Death occurred in 13 patients receiving enoxaparin and 14 patients receiving placebo at 90 days ( relative risk 0.93 , 95 % confidence interval 0.26 - 1.59 ) , and in 36 and 32 patients , respectively , at 1 year ( relative risk 1.13 , 95 % confidence interval 0.66 - 1.60 ) . Clinical thromboembolic events occurred in 5 patients receiving enoxaparin and 8 patients receiving placebo , and major bleeding occurred in 2 and 5 patients , respectively . CONCLUSIONS The pilot study indicated that the full study was not feasible . The decision to use prophylaxis pertains to only a small proportion of general medical patients hospitalized at VA medical centers , and this proportion is overestimated by chart review . The effect of low-dose heparin prophylaxis on clinical outcomes in hospitalized general medical patients remains uncertain INTRODUCTION There is an exponential rise of thromboembolic risk with age because of co-morbidities , immobility and pharmacotherapy . We aim ed to investigate the benefits and risks of heparin prophylaxis in very elderly patients ≥80 years and the type of heparin used in a subgroup analysis of the CERTIFY trial . PATIENTS / METHODS 3,239 patients were r and omized to 3,000 U aXa o.d . certoparin or 5,000 IU t.i.d . unfractionated heparin ( UFH ) for 8 - 20 days . RESULTS Patients ≥80 years ( n=1,365 ) were more likely to be female , had a lower mean bodyweight , were more frequently using antiplatelets and had a GFR below 30 ml/min/1.73 m(2 ) more often than patients < 80 years ( n=1,875 ) . The combined endpoint of proximal DVT , symptomatic non-fatal PE and VTE related death was experience by 5.26 % of patients ≥80 years versus 3.51 % in younger patients ( OR 1.53 ; 95%CI 1.05 - 2.21 ; p=0.03 ) . There were no significant differences in both minor ( OR 1.11 ; 95%CI 0.75 - 1.62 ) and major ( OR 2.53 ; 95%CI 0.93 - 6.86 ) bleeding risks  . Certoparin and UFH were equally effective in reducing thromboembolic risk in either age group . The risk of any ( OR 0.45 ; 95%CI 0.26 - 0.79 ) and minor bleeding ( OR 0.42 ; 95%CI 0.23 - 0.78 ) was reduced with certoparin in the very elderly only . There were more adverse events in elderly patients ( OR 1.26 ; 95%CI 1.1 - 1.46 ) , but rates were otherwise comparable . CONCLUSIONS The analysis confirmed the increased thromboembolic risk in very elderly patients , but demonstrated no increased bleeding risk . Certoparin and UFH were equally effective and safe with a reduced risk of minor bleeding  complications with certoparin in the very elderly In a multicentre , r and omized , double-blind controlled trial comparing the low-molecular-weight heparin enoxaparin ( 40 mg ) with a st and ard unfractionated heparin ( Ca-heparin , 3 x 5,000 U ) in deep-vein thrombosis prophylaxis in a high-risk group of 959 hospitalized medical patients , enoxaparin was at least as efficacious as st and ard heparin , with fewer adverse events BACKGROUND Extended- duration low-molecular-weight heparin has been shown to prevent venous thromboembolism ( VTE ) in high-risk surgical patients . OBJECTIVE To evaluate the efficacy and safety of extended- duration enoxaparin thromboprophylaxis in acutely ill medical patients . DESIGN R and omized , parallel , placebo-controlled trial . R and omization was computer-generated . Allocation was central ized . Patients , caregivers , and outcome assessors were blinded to group assignment . ( Clinical Trials.gov registration number : NCT00077753 ) SETTING : 370 sites in 20 countries across North and South America , Europe , and Asia . PATIENTS Acutely ill medical patients 40 years or older with recently reduced mobility ( bed rest or sedentary without [ level 1 ] or with [ level 2 ] bathroom privileges ) . Eligibility criteria for patients with level 2 immobility were amended to include only those who had additional VTE risk factors ( age > 75 years , history of VTE , or active or previous cancer ) after interim analyses suggested lower-than-expected VTE rates . INTERVENTION Enoxaparin , 40 mg/d subcutaneously ( 2975 patients ) , or placebo ( 2988 patients ) , for 28 + /- 4 days after receiving open-label enoxaparin for an initial 10 + /- 4 days . MEASUREMENTS Incidence of VTE up to day 28 and of major bleeding events up to 48 hours after the last study treatment dose . RESULTS Extended- duration enoxaparin reduced VTE incidence compared with placebo ( 2.5 % vs. 4 % ; absolute risk difference favoring enoxaparin , -1.53 % [ 95.8 % CI , -2.54 % to -0.52 % ] ) . Enoxaparin increased major bleeding events ( 0.8 % vs. 0.3 % ; absolute risk difference favoring placebo , 0.51 % [ 95 % CI , 0.12 % to 0.89 % ] ) . The benefits of extended- duration enoxaparin seemed to be restricted to women , patients older than 75 years , and those with level 1 immobility . LIMITATION Estimates of efficacy and safety for the overall trial population are difficult to interpret because of the change in eligibility criteria during the trial . CONCLUSION Use of extended- duration enoxaparin reduces VTE more than it increases major bleeding events in acutely ill medical patients with level 1 immobility , those older than 75 years , and women . PRIMARY FUNDING SOURCE Sanofi-aventis 166 patients aged 40 - 80 years were included in a controlled , r and omized , double-blind study to determine the efficacy and safety of a single daily injection of a low molecular weight ( LMW ) heparin for prevention of  deep-vein thrombosis  compared to low dose conventional heparin . Patients received 1 x 1.500 aPTT units of a LMW heparin fraction ( plus 2 x placebo injection ) or 3 x 5.000 IU of an unfractionated heparin . During 10 days of treatment , patients underwent repeated clinical investigation , serial impedance plethysmography , and Doppler sonography for detection of thrombosis of the lower limbs . Combined application of these methods revealed evidence of thrombosis in 4.5 % of patients on unfractionated heparin and 3.6 % of patients on LMW heparin .  Subcutaneous hematomas were significantly smaller in diameter upon treatment with LMW heparin ( p less than 0.001 ) . Antithrombin III levels were significantly higher at the end of the observation period in the LMW heparin group ( p less than 0.005 ) . Thrombocyte count , transaminases , creatinine , and haemoglobin did not change in either group . The results indicate that LMW heparin administered by a single s.c . dose daily may be as effective as low dose heparin in prevention of deep venous thrombosis in medical in patients BACKGROUND Despite the elevated risk for developing venous thromboembolic events in patients with heart failure , there are no r and omized , double-blind , controlled trial data on the comparison of low-molecular-weight heparin with unfractionated heparin ( UFH ) in this patient population . METHODS This was a subgroup analysis of the CERTIFY trial , which included 3,239 nonsurgical , acutely ill medical patients 70 years or older . Patients were r and omized to receive 3,000-U anti-Xa certoparin once daily or 5,000-IU UFH 3 times a day . The analysis was performed on a subgroup of 542 patients diagnosed with heart failure at hospital admission . RESULTS Patients with heart failure differed from patients without heart failure in that they were more likely using antiplatelets ( 67.2 % vs 48.9 % ; P < .0001 ) and had a lower glomerular filtration rate ( 8.0 % vs 5.5 % ; ≤ 30 mL/min per 1.73 m² ; P = .0232 ) . Thromboembolic risk was comparable except for a higher incidence of distal deep venous thrombosis ( DVT ) in patients with heart failure ( 10.80 % vs 7.26 % ; P = .0144 ) . Within the heart failure population , patient characteristics were comparable between r and omized treatment groups . The incidence of the primary end point ( proximal DVT , symptomatic nonfatal pulmonary embolism , and venous thromboembolism-related death combined ) was numerically , slightly smaller with certoparin ( 3.78 % vs 4.74 % with UFH ; odds ratio 0.79 , 95 % CI 0.32 - 1.94 ) , and the incidence of major bleeding was 0.72 % with certoparin versus 0.38 % with UFH . CONCLUSIONS Patients hospitalized for heart failure are at high risk for developing distal DVT and bleeding complications compared with acutely ill medical patients without heart failure . Within the heart failure population , the observed differences in prophylactic efficacy between 3,000-U anti-Xa certoparin once daily and 5,000-IU UFH 3 times a day were similar to those observed in the overall study population ; this suggests that certoparin might be at least as effective as UFH also in this subgroup . There were no relevant differences in bleeding risk or frequency of adverse events A r and omised trial was undertaken in one hundred patients with heart failure and /or chest infection to determine whether low-dose subcutaneous heparin reduced the frequency of deep vein thrombosis ( DVT )  in the legs . Heparin , ( 5000 units 8 hourly ) significantly reduced the frequency of DVT , diagnosed by the125I-fibrinogen scan technique , from 26 to 4 per cent ( p < 0.01 ) . Heparin was started within 12 hours of admission to hospital and continued until the patient was fully mobile . Heparin did not cause bleeding problems except for a 20 per cent incidence of injection site bruising . We therefore recommend prophylaxis with low-dose subcutaneous heparin in patients with heart failure or chest infection who require more than three days bed rest The Medical Patients with Enoxaparin ( MEDENOX ) trial was a r and omized , placebo-controlled study that defined the risk of venous thromboembolism ( VTE ) in acutely ill , immobilized , general medical patients and the efficacy of the low-molecular-weight heparin , enoxaparin , in preventing thrombosis . We performed a post-hoc analysis to evaluate the effect of 40 mg enoxaparin once daily on MEDENOX patient outcome in different types of acute medical illness ( heart failure , respiratory failure , infection , rheumatic disorder and inflammatory bowel disease ) and pre-defined risk factors ( chronic heart and chronic respiratory failure , age , immobility , previous VTE and cancer ) . The primary outcome was the occurrence of documented VTE between days 1 and 14 . The relative risk reduction [ 95 % confidence intervals ( CI ) ] for VTE comparing 40 mg enoxaparin with placebo in the subgroups were : acute heart failure , 0.29 ( 95 % CI , 0.10–0.84 ) ; acute respiratory failure , 0.25 ( 95 % CI , 0.10–0.65 ) ; acute infectious disease , 0.28 ( 95 % CI , 0.09–0.81 ) ; and acute rheumatic disorder , 0.48 ( 95 % CI , 0.11–2.16 ) . The relative risk reduction for VTE in the pre-defined risk factor subgroups were : chronic heart failure , 0.26 ( 
    Output:
    
There was no clear evidence that heparin had an effect on all-cause mortality and thrombocytopaenia .
There was no clear evidence that the effects of LMWH and UFH differed for the PE outcomes , all-cause mortality and thrombocytopaenia .
AUTHORS ' CONCLUSIONS The data from this review describe a reduction in the risk of DVT in patients presenting with an acute medical illness who receive heparin thromboprophylaxis .
This needs to be balanced against an increase in the risk of bleeding associated with thromboprophylaxis .
The analysis favoured LMWH compared with UFH , with a reduced risk of both DVT and bleeding