***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 COPD is a major cause of disability , but little is known about how disability develops in this condition . Methods The authors analysed data from the Function , Living , Outcomes and Work ( FLOW ) Study which enrolled 1202 Kaiser Permanente Northern California members with COPD at baseline and re-evaluated 1051 subjects at 2-year follow-up . The authors tested the specific hypothesis that the development of specific non-respiratory impairments ( abnormal body composition and muscle strength ) and functional limitations ( decreased lower extremity function , poor balance , mobility-related dyspnoea , reduced exercise performance and decreased cognitive function ) will determine the risk of disability in COPD , after controlling for respiratory impairment ( FEV1 and oxygen saturation ) . The  Valued Life Activities Scale  was used to assess disability in terms of a broad range of daily activities . The primary disability outcome measure was defined as an increase in the proportion of activities that can not be performed of 3.3 % or greater from baseline to 2-year follow-up ( the estimated minimal important difference ) . Multivariable logistic regression was used for analysis . Results Respiratory impairment measures were related to an increased prospect i ve risk of disability ( multivariate OR 1.75 ; 95 % CI 1.26 to 2.44 for 1 litre decrement of FEV1 and OR 1.57 per 5 % decrement in oxygen saturation ; 95 % CI 1.13 to 2.18 ) . Non-respiratory impairment ( body composition and lower extremity muscle strength ) and functional limitations ( lower extremity function , exercise performance , and mobility-related dyspnoea ) were all associated with an increased longitudinal risk of disability after controlling for respiratory impairment ( p<0.05 in all cases ) . Non-respiratory impairment and functional limitations were predictive of prospect i ve disability , above- and -beyond sociodemographic characteristics , smoking status and respiratory impairment ( area under the receiver operating characteristic curve increased from 0.65 to 0.75 ; p<0.001 ) . Conclusions Development of non-respiratory impairment and functional limitations , which reflect the systemic nature of COPD , appear to be critical determinants of disablement . Prevention and treatment of disability require a comprehensive approach to the COPD patient BACKGROUND Use of nutritional supplements in depleted patients with chronic obstructive pulmonary disease ( COPD ) requires optimization between positive effects on outcome and potential acute adverse effects on metabolism and exercise performance . OBJECTIVE The aim of this study was to investigate the acute effects of nutritional supplements on metabolism and exercise capacity in stable COPD patients . DESIGN In part 1 , the effects of 3 different energy loads ( placebo , 1046 kJ , and 2092 kJ ) with a normal distribution of macronutrients were investigated in 14 COPD patients . In part 2 , the effects of a fat-rich compared with a carbohydrate-rich supplement ( both 1046 kJ ) were studied in 11 COPD patients . The study was performed in a r and omized , double-blind , crossover fashion . Metabolic and ventilatory variables were measured postpr and ially and during a submaximal cycle endurance exercise test . RESULTS Overall , no immediate negative effects of the supplements were found in part 1 . A slight but significant postpr and ial increase in respiratory quotient was found after the 1046-kJ and 2092-kJ supplements compared with placebo . There was no significant difference in metabolism or exercise capacity after a fat-rich or carbohydrate-rich supplement . Surprisingly , the change in shortness of breath ( postpr and ial compared with prepr and ial ) was significantly greater after the fat-rich supplement . CONCLUSIONS An energy load up to 2092 kJ had no adverse immediate effect in COPD patients compared with placebo . The subjects who consumed the fat-rich supplement experienced more shortness of breath than did the subjects who consumed the carbohydrate-rich supplement The impact of oral nutritional supplementation during an acute exacerbation of COPD on functional status was assessed through measuring change in lung function , strength testing , and general well-being .  Subjects hospitalized for an acute exacerbation of COPD ( n = 33 ) were r and omized to extra nutritional support or the regular hospital care . They consumed an additional 10 kcal/kg/d . Outcome measures were measured at 2 wk as change scores . Forced vital capacity ( % predicted ) improved in the treatment group as compared with the control group ( + 8.7 % versus -3.5 % , p = 0.015 ) , and change in FEV1 was in the same direction but not significantly different ( p = 0.099 ) . There were no changes in h and grip strength or respiratory muscle strength , but there was a trend towards more improvement in the general well-being score ( + 11.96 versus -10.25 , p = 0.066 ) . Almost all subjects were in negative nitrogen balance , indicating muscle wasting . The degree of muscle wasting was strongly correlated with the dose of corticosteroids ( r = 0.73 , p < 0.005 ) . In conclusion , it is difficult to prevent important muscle wasting in patients with COPD treated with corticosteroids , but some small gains were observed with increased dietary intake Background In chronic respiratory failure ( CRF ) , body composition strongly predicts survival . Methods A prospect i ve r and omised controlled trial was undertaken in malnourished patients with CRF to evaluate the effects of 3 months of home rehabilitation on body functioning and composition .  122 patients with CRF on long-term oxygen therapy and /or non-invasive ventilation ( mean ( SD ) age 66 ( 10 ) years , 91 men ) were included from eight respiratory units ; 62 were assigned to home health education ( controls ) and 60 to multimodal nutritional rehabilitation combining health education , oral nutritional supplements , exercise and oral testosterone for 90 days . The primary endpoint was exercise tolerance assessed by the 6-min walking test ( 6MWT ) . Secondary endpoints were body composition , quality of life after 3 months and 15-month survival . Results Mean ( SD ) baseline arterial oxygen tension was 7.7 ( 1.2 ) kPa , forced expiratory volume in 1 s 31 (13)% predicted , body mass index ( BMI ) 21.5 ( 3.9 ) kg/m2 and fat-free mass index ( FFMI ) 15.5 ( 2.4 ) kg/m2 . The intervention had no significant effect on 6MWT . Improvements ( treatment effect ) were seen in BMI ( + 0.56 kg/m2 , 95 % CI 0.18 to 0.95 , p=0.004 ) , FFMI ( + 0.60 kg/m2 , 95 % CI 0.15 to 1.05 , p=0.01 ) , haemoglobin ( + 9.1 g/l , 95 % CI 2.5 to 15.7 , p=0.008 ) , peak workload ( + 7.2 W , 95 % CI 3.7 to 10.6 , p<0.001 ) , quadriceps isometric force ( + 28.3 N , 95 % CI 7.2 to 49.3 , p=0.009 ) , endurance time ( + 5.9 min , 95 % CI 3.1 to 8.8 , p<0.001 ) and , in women , Chronic Respiratory Question naire ( + 16.5 units , 95 % CI 5.3 to 27.7 , p=0.006 ) . In a multivariate Cox analysis , only rehabilitation in a per- protocol analysis predicted survival ( HR 0.27 , 95 % CI 0.07 to 0.95 , p=0.042 ) . Conclusions Multimodal nutritional rehabilitation aim ed at improving body composition increased exercise tolerance , quality of life in women and survival in compliant patients , supporting its incorporation in the treatment of malnourished patients with CRF . Clinical Trial number NCT00230984 Nutritional depletion commonly occurs in patients with COPD , causing muscle wasting and impaired physiologic function . Two hundred seventeen patients with COPD participated in a placebo-controlled , r and omized trial investigating the physiologic effects of nutritional intervention alone ( N ) for 8 wk or combined with the anabolic steroid n and rolone decanoate ( N + A ) . N and rolone decanoate or placebo ( P ) was injected intramuscularly ( women , 25 mg ; men , 50 mg ) in a double-blind fashion on Days 1 , 15 , 29 , and 43 . Nutritional intervention consisted of a daily high caloric supplement ( 420 kcal ; 200 ml ) . Also , all patients participated in an exercise program . In the depleted patients , both treatment regimens induced a similar significant body weight gain ( 2.6 kg ) but different body compositional changes . Particularly in the last 4 wk of treatment , weight gain in the N group was predominantly due to an expansion of fat mass ( p < 0.03 versus P and N + A ) , whereas the relative changes in fat-free mass ( FFM ) and other measures of muscle mass were more favorable in the N + A group ( p < 0.03 versus P ) . Maximal inspiratory mouth pressure improved within both treatment groups in the first 4 wk of treatment , but after 8 wk only N + A was significantly different from P ( p < 0.03 ) . Nutritional supplementation in combination with a short course of anabolic steroids may enhance the gain in FFM and respiratory muscle function in depleted patients with COPD without causing adverse side effects The objective of the study was to further unravel the prognostic significance of body weight changes in patients with COPD . Two survival analyses were performed : ( 1 ) a retrospective study , including 400 patients with COPD none of whom had received nutritional therapy ; ( 2 ) a post hoc analysis of a prospect i ve study , including 203 patients with COPD who had participated in a r and omized placebo-controlled trial . There was no overlap between the patient groups . Baseline characteristics of all patients were collected on admission to a pulmonary rehabilitation center in stable clinical condition . In the prospect i ve r and omized placebo-controlled trial , the physiologic effects of nutritional therapy alone ( n = 71 ) or in combination with anabolic steroid treatment ( n = 67 ) after 8 wk was studied in patients with COPD prestratified into a depleted group and a nondepleted group . Mortality was assessed as overall mortality . The Cox proportional hazards model was used to quantify the relationship between the baseline variables age , sex , spirometry , arterial blood gases , body mass index ( BMI ) , smoking , and subsequent overall mortality . Additionally , the influence of treatment response on mortality was investigated in the prospect i ve study . The retrospective study revealed that low BMI ( p < 0.001 ) , age ( p < 0.0001 ) and low PaO2 ( p < 0.05 ) were significant independent predictors of increased mortality . After stratification of the group into BMI quintiles a threshold value of 25 kg/m2 was identified below which the mortality risk was clearly increased . In the prospect i ve study , weight gain ( > 2 kg/8 wk ) in depleted and nondepleted patients with COPD , as well as increase in maximal inspiratory mouth pressure during the 8-wk treatment , were significant predictors of survival . On Cox regression analysis weight change entered as a time-dependent covariate remained an independent predictor of mortality in addition to all variables that were entered in the retrospective study . The combined results of the two survival analyses provide evidence to support the hypothesis that body weight has an independent effect on survival in COPD . Moreover the negative effect of low body weight can be reversed by appropriate therapy in some of the patients with COPD Study objectives Patients with chronic obstructive pulmonary disease ( COPD ) have low exercise capacity and low content of high energetic phosphates in their skeletal muscles . The aim of the present study was to investigate whether creatine supplementation together with exercise training may increase physical performance compared with exercise training in patients with COPD . Design In a r and omized , double-blind , placebo-controlled study , 23 patients with COPD ( forced expiratory volume in one second [ FEV1 ] < 70 % of predicted ) were r and omized to oral creatine ( n = 13 ) or placebo ( n = 10 ) supplementation during an 8-week rehabilitation programme including exercise training . Physical performance was assessed by Endurance Shuttle Walking Test ( ESWT ) , dyspnea and leg fatigue with Borg CR-10 , quality of life with St George ’s Respiratory Question naire ( SGRQ ) . In addition , lung function test , artery blood gases , grip strength test , muscle strength and fatigue in knee extensors were measured . Results COPD patients receiving creatine supplementation increased their average walking time by 61 % ( ESWT ) ( p < 0.05 ) after the training period compared with 48 % ( p = 0.07 ) in the placebo group . Rated dyspnea directly after the ESWT decreased significantly from 7 to 5 ( p < 0.05 ) in the creatine group . However , the difference between the groups was not statistically significant neither in walking time nor in rated dyspnea . Creatine supplementation did not increase the health related quality of life , lung function , ar 
    Output:
    
It also led to improved exercise performance and enhancement of exercise rehabilitation programmes .
This systematic review and meta- analysis demonstrates that nutritional support in COPD results in significant improvements in a number of clinical ly relevant functional outcomes , complementing a previous review showing improvements in nutritional intake and weight