human
***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: We prospect ively measured functional performances ( Western Ontario and McMaster Universities Osteoarthritis Index , Short Form-36 , 2-minute walk test , and timed get-up- and -go test ) of patients who underwent total hip arthroplasty ( THA )  and had serum vitamin D levels tested during the preoperative evaluation . Of 219 patients , 102 ( 46.6 % ) had low vitamin D levels ( 25-hydroxyvitamin D<30 ng/mL ) . Low vitamin D status did not adversely affect short-term function at 6 weeks after THA . In addition , there was no association between serum vitamin D levels and the within-patient changes of scores of each outcome measurement . Because this 6-week period is generally adequate to correct vitamin D deficiency , orthopedic surgeons can safely perform THA without delay . Nevertheless , because vitamin D deficiency impairs bone quality , patients with low vitamin D levels should be treated once identified Prospect i ve epidemiologic studies generally rely on 1 baseline biologic sample from participants for measurement of prediagnostic biomarkers , assuming that 1 measurement adequately represents the participant 's " typical " level . The body of work assessing the reproducibility of circulating serum 25-hydroxyvitamin D ( 25(OH)D ) levels over time focuses almost exclusively on population s of European descent , and data for vitamin D-binding protein ( VDBP ) are virtually nonexistent . Thus , the authors measured levels of serum 25(OH)D and VDBP twice in sample s collected between 2005 and 2008 from 225 participants ( 155 black , 70 white ) in the Southern Community Cohort Study .  Reproducibility for 25(OH)D was uniformly high , with adjusted intraclass correlation coefficients ( ICCs ) of 0.84 ( 95 % confidence interval ( CI ) : 0.79 , 0.88 ) for blacks and 0.92 ( 95 % CI : 0.87 , 0.95 ) for whites , and there was substantial agreement for assignment of 25(OH)D quartile ( κ = 0.83 , 95 % CI : 0.78 , 0.87 ) and vitamin D adequacy status ( κ = 0.76 , 95 % CI : 0.69 , 0.83 ) . VDBP levels were highly stable over time , with adjusted ICCs of 0.97 ( 95 % CI : 0.96 , 0.98 ) for blacks and 0.96 ( 95 % CI : 0.93 , 0.97 ) for whites . These findings suggest that single , baseline 25(OH)D and VDBP serum measurements provide reasonably representative measures of these compounds for both white and black adults , demonstrating their utility as epidemiologic biomarkers in prospect i ve studies AIMS A significant proportion of cardiac surgical patients develop critical post-operative complications . We aim ed to investigate the association of pre-operative 25-hydroxyvitamin D ( 25(OH)D ) levels with major cardiac and cerebrovascular events ( MACCE ) in cardiac surgical patients . METHODS AND RESULTS From January 2010 to August 2011 , we consecutively measured circulating 25(OH)D in 4418 operated patients . Of the study cohort , 38.0 % had deficient 25(OH)D values ( < 30 nmol/L ) and additional 32.3 % had insufficient values ( 30 - 49.9 nmol/L ) , whereas only 3.1 % had values > 100 nmol/L. The incidence of MACCE was 11.5 % . In multivariable-adjusted logistic regression models , the odds ratio of MACCE at deficient , inadequate , and high 25(OH)D levels was 2.23 [ 95 % confidence interval ( CI ) : 1.31 - 3.79 ] , 1.73 ( 95 % CI : 1.01 - 2.96 ) and 2.34 ( 95 % CI : 1.12 - 4.89 ) , respectively , compared with 25(OH)D levels of 75 - 100 nmol/L. A U-shaped association with circulating 25(OH)D was also present for duration of mechanical ventilatory support and intensive care unit stay . Multivariable-adjusted 6- and 12-month mortality were higher in patients with deficient 25(OH)D levels compared with patients with 25(OH)D levels of 75 - 100 nmol/L. CONCLUSION Deficient 25(OH)D levels are prevalent in cardiac surgical patients in Central Europe and are independently associated with the risk of MACCE . Further research should clarify the potential of vitamin D supplements in reducing cardiovascular risk in vitamin D-deficient patients and also the mechanisms leading to adverse effects on the cardiovascular system in the small group of patients with 25(OH)D levels > 100 Flaws in the design , conduct , analysis , and reporting of r and omised trials can cause the effect of an intervention to be underestimated or overestimated . The Cochrane Collaboration ’s tool for assessing risk of bias aims to make the process clearer and more Background Hypovitaminosis D is particularly common among older people with a proximal femoral ( hip ) fracture . There are currently no agreed strategies for vitamin D replenishment after hip fracture surgery . The REVITAHIP Study is a multisite , double-blinded r and omized-controlled trial investigating the effects of an oral vitamin D loading dose on gait velocity after hip fracture surgery . We describe the baseline characteristics of participants , aim ing to document hypovitaminosis D and its associations after hip fracture . Methods Participants , over 65 , recruited within 7 days following hip fracture surgery from 3 Australia hospitals , were r and omly allocated to receive a loading dose of vitamin D3 ( 250,000IU ) or placebo , followed by oral maintenance vitamin D3/calcium ( 800 IU/500 mg ) and the usual hip fracture rehabilitation pathway . Demographic and clinical data were collected , including surgical procedure , pre-fracture functional status , Mini Mental State Examination ( MMSE ) score , serum 25-hydroxyvitamin D ( 25-OHD ) , Verbal Rating Scale ( VRS ) for pain , grip strength and gait velocity . The associations of baseline 25-OHD levels with demographic and clinical data were assessed using Pearson ’s correlation , ANOVA and regression analyses . Results Two-hundred- and -eighteen people with hip fracture participated in the study . Mean age was 83.9+/-7.2 years , 77 % were women and 82 % lived in private homes . Fifty-six percent had a subcapital fracture . Mean comorbidity count was 3.13+/-2.0 . Mean MMSE was 26.1+/-3.9 . Forty-seven percent of participants had hypovitaminosis D ( < 50 nmol/L ) . Multivariate regression models demonstrated higher baseline vitamin D levels were significantly associated with higher premorbid Barthel index scores , lower post-operative VRS pain levels and use of vitamin D. Conclusion This study cohort shared similar demographic characteristics and comorbidities with other cohorts of people with hip fracture , with the probable exception of less cognitive impairment . Hypovitaminosis D was not as prevalent as previously documented . Patients taking vitamin D supplements and with higher premorbid Barthel index , reflecting greater independence and activity , tended to have higher 25-OHD levels at baseline . Further , lower VRS pain ratings following surgery were associated with higher vitamin D levels . Such associations will need further investigation to determine causation . ( ANZCTR number , ACTRN12610000392066).Trial registration The protocol for this study is registered with the Australian New Zeal and Clinical Trials Registry ANZCTRN ACTRN12610000392066 Background . Administration of the vitamin D hormone calcitriol improves survival in solid-organ transplanted experimental animals . We investigated whether lower serum calcitriol concentrations are associated with increased 1-year mortality in cardiac transplant recipients . Methods . We prospect ively recruited 171 patients who underwent cardiac transplantation at out institution between May 2004 and April 2006 . We assessed  calciotropic hormones , inflammation markers , and renal function preoperatively and on postoperative days 6 ( t1 ) and 21 ( t2 ) . Results . Serum creatinine and C-reactive protein increased , whereas calcitriol decreased significantly after transplantation ( P<0.001 ) . As determined by multivariable Cox regression analysis , the calcitriol level at t2 was an independent predictor of 1-year mortality . One-year mortality was 3.7 per 100 person-years in the tertile with the highest calcitriol concentrations at t2 ( > 18 pg/mL ) , 13.2 per 100 person-years in the intermediate tertile ( 11–18 pg/mL ) , and 32.1 per 100 person-years in the tertile with the lowest calcitriol concentrations at t2 ( < 11 pg/mL ) ( P<0.001 ) .  25-hydroxyvitamin D deficiency ( serum concentrations below 10 ng/mL ) , renal insufficiency ( serum creatinine ≥1.6 mg/dL ) , and high serum concentrations of the inflammation markers C-reactive peptide and tumor necrosis factor-&agr ; were predictors of a serum calcitriol concentration below 11 pg/mL ( P=0.037–0.001 ) . Conclusions . Low postoperative calcitriol concentrations are independently associated with high 1-year mortality in cardiac transplant recipients . A causal relationship has yet to be proven by intervention trials using active vitamin Objective : To investigate the interrelationship between cardiac surgery , age , circulating concentrations of the vitamin D hormone 1,25-dihydroxyvitamin D , and clinical outcome . Design : Prospect i ve , monocentric , two-arm parallel study . Setting : Tertiary Heart and Diabetes Center in the Federal State of North Rhine-Westphalia , Germany . Patients : Twenty-nine cardiac surgical patients aged ⩽65 yrs and 30 patients ≥75 yrs . Measurements : We assessed  1,25-dihydroxyvitamin D and other biochemical parameters of mineral metabolism ( calcium , phosphate , 25-hydroxyvitamin D , and parathyroid hormone ) , various inflammatory markers ( C-reactive protein , interleukin-6 and 8) , and different immunological parameters ( CD4 and CD8 cells , monocyte HLA-DR expression ) . We collected blood sample s preoperatively , immediately after surgery , and on postoperative days 1 , 5 , and 30 . In addition , we assessed adverse outcome until discharge as a composite of myocardial infa rct ion , low cardiac output syndrome , infection , stroke , or in-hospital death . Results : There were significant transient cardiac surgery-related fluctuations in 1,25-dihydroxyvitamin D and the aforementioned parameters of mineral metabolism , inflammation , and immune status . Compared to younger patients , older patients had consistently lower 1,25-dihydroxyvitamin D and phosphate levels ( p = .013 and p = .036 , respectively ) and significantly higher interleukin 6 and 8 levels ( p = .008 and p < .001 , respectively ) . Circulating 1,25-dihydroxyvitamin D was directly related to glomerular filtration rate ( R2 = .227 ; p < .001 ) and inversely related to interleukin 6 ( R2 = .105 ; p = .012 ) . The rate of adverse outcome tended to be higher in older than in younger patients ( 20.0 % vs. 3.5 % ; p = .081 ) . In risk score-adjusted logistic regression analysis , adverse outcome risk decreased by 7.7 % ( SE : 3.7 % ) for each pmol/L increment in 1,25-dihydroxyvitamin D ( p = .037 ) . Conclusions : Circulating 1,25-dihydroxyvitamin D levels fluctuate in relation to cardiac surgery . Low 1,25-dihydroxyvitamin D levels are associated with inflammatory processes and age-related differences in clinical outcome . Future studies should determine whether therapies aim ed at treating low 1,25-dihydroxyvitamin D levels can improve the outcome in older cardiac surgery patients This article introduces the approach of GRADE to rating  quality of evidence .  GRADE specifies four categories-high , moderate , low , and very low-that are applied to a body of evidence , not to individual studies . In the context of a systematic review , quality reflects our confidence that the estimates of the effect are correct . In the context of recommendations , quality reflects our confidence that the effect estimates are adequate to support a particular recommendation . R and omized trials begin as high- quality evidence , observational studies as low quality . " Quality " as used in GRADE means more than risk of bias and so may also be compromised by im 
    Output:
    
agent
In conclusion , this review supports the hypothesis that hypovitaminosis D is associated with adverse outcomes after diverse surgical procedures .
***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: We prospect ively measured functional performances ( Western Ontario and McMaster Universities Osteoarthritis Index , Short Form-36 , 2-minute walk test , and timed get-up- and -go test ) of patients who underwent total hip arthroplasty ( THA )  and had serum vitamin D levels tested during the preoperative evaluation . Of 219 patients , 102 ( 46.6 % ) had low vitamin D levels ( 25-hydroxyvitamin D<30 ng/mL ) . Low vitamin D status did not adversely affect short-term function at 6 weeks after THA . In addition , there was no association between serum vitamin D levels and the within-patient changes of scores of each outcome measurement . Because this 6-week period is generally adequate to correct vitamin D deficiency , orthopedic surgeons can safely perform THA without delay . Nevertheless , because vitamin D deficiency impairs bone quality , patients with low vitamin D levels should be treated once identified Prospect i ve epidemiologic studies generally rely on 1 baseline biologic sample from participants for measurement of prediagnostic biomarkers , assuming that 1 measurement adequately represents the participant 's " typical " level . The body of work assessing the reproducibility of circulating serum 25-hydroxyvitamin D ( 25(OH)D ) levels over time focuses almost exclusively on population s of European descent , and data for vitamin D-binding protein ( VDBP ) are virtually nonexistent . Thus , the authors measured levels of serum 25(OH)D and VDBP twice in sample s collected between 2005 and 2008 from 225 participants ( 155 black , 70 white ) in the Southern Community Cohort Study .  Reproducibility for 25(OH)D was uniformly high , with adjusted intraclass correlation coefficients ( ICCs ) of 0.84 ( 95 % confidence interval ( CI ) : 0.79 , 0.88 ) for blacks and 0.92 ( 95 % CI : 0.87 , 0.95 ) for whites , and there was substantial agreement for assignment of 25(OH)D quartile ( κ = 0.83 , 95 % CI : 0.78 , 0.87 ) and vitamin D adequacy status ( κ = 0.76 , 95 % CI : 0.69 , 0.83 ) . VDBP levels were highly stable over time , with adjusted ICCs of 0.97 ( 95 % CI : 0.96 , 0.98 ) for blacks and 0.96 ( 95 % CI : 0.93 , 0.97 ) for whites . These findings suggest that single , baseline 25(OH)D and VDBP serum measurements provide reasonably representative measures of these compounds for both white and black adults , demonstrating their utility as epidemiologic biomarkers in prospect i ve studies AIMS A significant proportion of cardiac surgical patients develop critical post-operative complications . We aim ed to investigate the association of pre-operative 25-hydroxyvitamin D ( 25(OH)D ) levels with major cardiac and cerebrovascular events ( MACCE ) in cardiac surgical patients . METHODS AND RESULTS From January 2010 to August 2011 , we consecutively measured circulating 25(OH)D in 4418 operated patients . Of the study cohort , 38.0 % had deficient 25(OH)D values ( < 30 nmol/L ) and additional 32.3 % had insufficient values ( 30 - 49.9 nmol/L ) , whereas only 3.1 % had values > 100 nmol/L. The incidence of MACCE was 11.5 % . In multivariable-adjusted logistic regression models , the odds ratio of MACCE at deficient , inadequate , and high 25(OH)D levels was 2.23 [ 95 % confidence interval ( CI ) : 1.31 - 3.79 ] , 1.73 ( 95 % CI : 1.01 - 2.96 ) and 2.34 ( 95 % CI : 1.12 - 4.89 ) , respectively , compared with 25(OH)D levels of 75 - 100 nmol/L. A U-shaped association with circulating 25(OH)D was also present for duration of mechanical ventilatory support and intensive care unit stay . Multivariable-adjusted 6- and 12-month mortality were higher in patients with deficient 25(OH)D levels compared with patients with 25(OH)D levels of 75 - 100 nmol/L. CONCLUSION Deficient 25(OH)D levels are prevalent in cardiac surgical patients in Central Europe and are independently associated with the risk of MACCE . Further research should clarify the potential of vitamin D supplements in reducing cardiovascular risk in vitamin D-deficient patients and also the mechanisms leading to adverse effects on the cardiovascular system in the small group of patients with 25(OH)D levels > 100 Flaws in the design , conduct , analysis , and reporting of r and omised trials can cause the effect of an intervention to be underestimated or overestimated . The Cochrane Collaboration ’s tool for assessing risk of bias aims to make the process clearer and more Background Hypovitaminosis D is particularly common among older people with a proximal femoral ( hip ) fracture . There are currently no agreed strategies for vitamin D replenishment after hip fracture surgery . The REVITAHIP Study is a multisite , double-blinded r and omized-controlled trial investigating the effects of an oral vitamin D loading dose on gait velocity after hip fracture surgery . We describe the baseline characteristics of participants , aim ing to document hypovitaminosis D and its associations after hip fracture . Methods Participants , over 65 , recruited within 7 days following hip fracture surgery from 3 Australia hospitals , were r and omly allocated to receive a loading dose of vitamin D3 ( 250,000IU ) or placebo , followed by oral maintenance vitamin D3/calcium ( 800 IU/500 mg ) and the usual hip fracture rehabilitation pathway . Demographic and clinical data were collected , including surgical procedure , pre-fracture functional status , Mini Mental State Examination ( MMSE ) score , serum 25-hydroxyvitamin D ( 25-OHD ) , Verbal Rating Scale ( VRS ) for pain , grip strength and gait velocity . The associations of baseline 25-OHD levels with demographic and clinical data were assessed using Pearson ’s correlation , ANOVA and regression analyses . Results Two-hundred- and -eighteen people with hip fracture participated in the study . Mean age was 83.9+/-7.2 years , 77 % were women and 82 % lived in private homes . Fifty-six percent had a subcapital fracture . Mean comorbidity count was 3.13+/-2.0 . Mean MMSE was 26.1+/-3.9 . Forty-seven percent of participants had hypovitaminosis D ( < 50 nmol/L ) . Multivariate regression models demonstrated higher baseline vitamin D levels were significantly associated with higher premorbid Barthel index scores , lower post-operative VRS pain levels and use of vitamin D. Conclusion This study cohort shared similar demographic characteristics and comorbidities with other cohorts of people with hip fracture , with the probable exception of less cognitive impairment . Hypovitaminosis D was not as prevalent as previously documented . Patients taking vitamin D supplements and with higher premorbid Barthel index , reflecting greater independence and activity , tended to have higher 25-OHD levels at baseline . Further , lower VRS pain ratings following surgery were associated with higher vitamin D levels . Such associations will need further investigation to determine causation . ( ANZCTR number , ACTRN12610000392066).Trial registration The protocol for this study is registered with the Australian New Zeal and Clinical Trials Registry ANZCTRN ACTRN12610000392066 Background . Administration of the vitamin D hormone calcitriol improves survival in solid-organ transplanted experimental animals . We investigated whether lower serum calcitriol concentrations are associated with increased 1-year mortality in cardiac transplant recipients . Methods . We prospect ively recruited 171 patients who underwent cardiac transplantation at out institution between May 2004 and April 2006 . We assessed  calciotropic hormones , inflammation markers , and renal function preoperatively and on postoperative days 6 ( t1 ) and 21 ( t2 ) . Results . Serum creatinine and C-reactive protein increased , whereas calcitriol decreased significantly after transplantation ( P<0.001 ) . As determined by multivariable Cox regression analysis , the calcitriol level at t2 was an independent predictor of 1-year mortality . One-year mortality was 3.7 per 100 person-years in the tertile with the highest calcitriol concentrations at t2 ( > 18 pg/mL ) , 13.2 per 100 person-years in the intermediate tertile ( 11–18 pg/mL ) , and 32.1 per 100 person-years in the tertile with the lowest calcitriol concentrations at t2 ( < 11 pg/mL ) ( P<0.001 ) .  25-hydroxyvitamin D deficiency ( serum concentrations below 10 ng/mL ) , renal insufficiency ( serum creatinine ≥1.6 mg/dL ) , and high serum concentrations of the inflammation markers C-reactive peptide and tumor necrosis factor-&agr ; were predictors of a serum calcitriol concentration below 11 pg/mL ( P=0.037–0.001 ) . Conclusions . Low postoperative calcitriol concentrations are independently associated with high 1-year mortality in cardiac transplant recipients . A causal relationship has yet to be proven by intervention trials using active vitamin Objective : To investigate the interrelationship between cardiac surgery , age , circulating concentrations of the vitamin D hormone 1,25-dihydroxyvitamin D , and clinical outcome . Design : Prospect i ve , monocentric , two-arm parallel study . Setting : Tertiary Heart and Diabetes Center in the Federal State of North Rhine-Westphalia , Germany . Patients : Twenty-nine cardiac surgical patients aged ⩽65 yrs and 30 patients ≥75 yrs . Measurements : We assessed  1,25-dihydroxyvitamin D and other biochemical parameters of mineral metabolism ( calcium , phosphate , 25-hydroxyvitamin D , and parathyroid hormone ) , various inflammatory markers ( C-reactive protein , interleukin-6 and 8) , and different immunological parameters ( CD4 and CD8 cells , monocyte HLA-DR expression ) . We collected blood sample s preoperatively , immediately after surgery , and on postoperative days 1 , 5 , and 30 . In addition , we assessed adverse outcome until discharge as a composite of myocardial infa rct ion , low cardiac output syndrome , infection , stroke , or in-hospital death . Results : There were significant transient cardiac surgery-related fluctuations in 1,25-dihydroxyvitamin D and the aforementioned parameters of mineral metabolism , inflammation , and immune status . Compared to younger patients , older patients had consistently lower 1,25-dihydroxyvitamin D and phosphate levels ( p = .013 and p = .036 , respectively ) and significantly higher interleukin 6 and 8 levels ( p = .008 and p < .001 , respectively ) . Circulating 1,25-dihydroxyvitamin D was directly related to glomerular filtration rate ( R2 = .227 ; p < .001 ) and inversely related to interleukin 6 ( R2 = .105 ; p = .012 ) . The rate of adverse outcome tended to be higher in older than in younger patients ( 20.0 % vs. 3.5 % ; p = .081 ) . In risk score-adjusted logistic regression analysis , adverse outcome risk decreased by 7.7 % ( SE : 3.7 % ) for each pmol/L increment in 1,25-dihydroxyvitamin D ( p = .037 ) . Conclusions : Circulating 1,25-dihydroxyvitamin D levels fluctuate in relation to cardiac surgery . Low 1,25-dihydroxyvitamin D levels are associated with inflammatory processes and age-related differences in clinical outcome . Future studies should determine whether therapies aim ed at treating low 1,25-dihydroxyvitamin D levels can improve the outcome in older cardiac surgery patients This article introduces the approach of GRADE to rating  quality of evidence .  GRADE specifies four categories-high , moderate , low , and very low-that are applied to a body of evidence , not to individual studies . In the context of a systematic review , quality reflects our confidence that the estimates of the effect are correct . In the context of recommendations , quality reflects our confidence that the effect estimates are adequate to support a particular recommendation . R and omized trials begin as high- quality evidence , observational studies as low quality . " Quality " as used in GRADE means more than risk of bias and so may also be compromised by im 
    Output:
    