***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: In recent years quality of life instruments have been featured as primary outcomes in many r and omized trials . One of the challenges facing the investigator using such measures is determining the significance of any differences observed , and communicating that significance to clinicians who will be applying the trial results . We have developed an approach to elucidating the significance of changes in score in quality of life instruments by comparing them to global ratings of change . Using this approach we have established a plausible range within which the minimal clinical ly important difference ( MCID ) falls . In three studies in which instruments measuring  dyspnea , fatigue , and emotional function in patients with chronic heart and lung disease were applied the MCID was represented by mean change in score of approximately 0.5 per item , when responses were presented on a seven point Likert scale . Furthermore , we have established ranges for changes in question naire scores that correspond to moderate and large changes in the domains of interest . This information will be useful in interpreting question naire scores , both in individuals and in groups of patients participating in controlled trials , and in the planning of new trials STUDY OBJECTIVES The purpose s of this study were as follows : ( 1 ) to determine whether physical performance , quality of life , and dyspnea with activities of daily living improved following both short-term and long-term pulmonary rehabilitation ( PR ) across multiple hospital outpatient programs ; ( 2 ) to examine the differences in these parameters between men and women ; and ( 3 ) to determine what relationships existed between the psychosocial parameters and the results of the 6-min walk ( 6MW ) test performance across programs . DESIGN Non-experimental , prospect i ve , and comparative . SETTING Seven outpatient hospital PR programs from urban and rural setting s across North Carolina . PARTICIPANTS Three hundred nine women and 281 men who were 20 to 93 years of age ( mean [ + /- SD ] age , 66.7 + /- 11.1 years ) with chronic lung disease . INTERVENTIONS All 6MW tests and health surveys  were administered prior to and immediately following 12 and 24 weeks of supervised PR participation . Scores from the 6MW tests , the Ferrans and Powers quality of life index-pulmonary version III ( QLI ) , the Medical Outcomes Study 36-item short form ( SF-36 ) , and the University of California at San Diego shortness of breath question naire ( SOBQ ) were compared at PR entry , at 12 weeks , and at 24 weeks for differences by gender with repeated- measures analysis of variance . The study entry and follow-up SF-36 physical and mental component summary scores , the QLI health/function and overall scores , and the SOBQ scores were also compared to the 6MW test scores with Pearson correlation coefficient analysis . RESULTS The mean summary scores on the SF-36 and the QLI increased after 12 weeks of PR ( p < 0.05 ) , and improvements were maintained by 24 weeks of PR participation ( p < 0.05 ) . Scores on the SOBQ improved after 12 weeks ( p < 0.001 ) among the short-term participants , but not until after 24 weeks among the long-term participants ( p = 0.009 ) . The 6MW test performance improved after 12 weeks ( p < 0.001 ) and again from 12 to 24 weeks ( p = 0.002 ) in the long-term participants . No relevant correlational relationships were found between 6MW scores and the summary scores of the administered surveys ( r = -0.43 to 0.36 ) . CONCLUSIONS Physical performance , as measured by the 6MW test , continued to improve with up to 24 weeks of PR participation . Quality -of-life measures and the perception of dyspnea improved after 12 weeks of PR participation , with improvements maintained by 24 weeks of PR participation . It is recommended that PR patients participate in supervised PR for at least 24 weeks to gain and maintain optimal health benefits The purpose of this study was to investigate the effects on activities of daily living , quality of life , and exercise tolerance of a comprehensive out-patient rehabilitation programme for patients with moderate-to-severe chronic obstructive pulmonary disease . In this r and omized and controlled trial , the main outcome measures were Activities of Daily Living ( ADL ) score , York Quality of Life Question naire ( YQLQ ) score , Chronic Respiratory Disease Question naire ( CRDQ ) score , 6 min walking distance ( 6MWD ) , forced expiratory volume in one second ( FEV1 ) , and forced vital capacity ( FVC ) . The rehabilitation programme included physical training , occupational therapy , education , and smoking cessation therapy , and lasted for 12 weeks . The patients were evaluated at entry , halfway through , and at the end of the programme . Follow-up was at 24 weeks . Forty seven patients were recruited , and 16 in each group completed the trial . There were significant differences in the improvements in ADL and CRDQ between the control and the treatment groups at 12 and 24 weeks , and at 24 weeks , respectively . At 6 , 12 and 24 weeks , improvements in the 6MWD were 21.6 versus 79.8 , 36.1 versus 113.1 and 21.4 versus 96.2 for control and treatment groups , respectively ( p<0.004 ) . A correlation matrix showed only ADL and 6MWD to be significantly correlated ; the matrix was also used to vali date the translated question naires . The programme required 124 staff-hours in total . An inexpensive , comprehensive out-patient rehabilitation programme can produce long-term improvement in activities of daily living , quality of life , and exercise tolerance in patients with moderate-to-severe chronic obstructive pulmonary disease Maintenance of  physical activity following pulmonary rehabilitation remains a challenge for patients with chronic obstructive pulmonary disease ( COPD ) . The objectives of this study were to identify patterns of endurance activity after completion of pulmonary rehabilitation and to characterise people who succeed and those who have difficulty maintaining endurance activity . In a longitudinal study embedded within a r and omised clinical trial , 206 individuals with COPD underwent a 3-month pulmonary rehabilitation programme .  Weekly duration of endurance activity  was assessed at 4 , 6 , 8 and 12 months after the start of rehabilitation .  Trajectory modelling  was used to determine the most common patterns of activity during the post-rehabilitation phase from 4–12 months . Three distinct patterns were identified , two of which indicated difficulty in maintaining endurance activity : 61 individuals reported a high activity level at 4 months ( 2.7 h·week−1 ) and stayed high ; 114 individuals started at a low activity level ( mean 1.0 h·week−1 ) and stayed low ; and 31 individuals started high ( 3.0 h·week−1 ) and declined . The low activity group was characterised by more severe disease and greater respiratory impairment . The high and declined group had less severe disease and respiratory impairment , but reported greater barriers to exercise . Pulmonary rehabilitation should include interventions aim ed at minimising barriers , in order to induce long-term behaviour change OBJECTIVE : To test the feasibility of creating a valid and reliable checklist with the following features : appropriate for assessing both r and omised and non-r and omised studies ; provision of both an overall score for study quality and a profile of scores not only for the quality of reporting , internal validity ( bias and confounding ) and power , but also for external validity . DESIGN : A pilot version was first developed , based on epidemiological principles , review s , and existing checklists for r and omised studies . Face and content validity were assessed by three experienced review ers and reliability was determined using two raters assessing 10 r and omised and 10 non-r and omised studies . Using different raters , the checklist was revised and tested for internal consistency ( Kuder-Richardson 20 ) , test-retest and inter-rater reliability ( Spearman correlation coefficient and sign rank test ; kappa statistics ) , criterion validity , and respondent burden . MAIN RESULTS : The performance of the checklist improved considerably after revision of a pilot version . The Quality Index had high internal consistency ( KR-20 : 0.89 ) as did the subscales apart from external validity ( KR-20 : 0.54 ) . Test-retest ( r 0.88 ) and inter-rater ( r 0.75 ) reliability of the Quality Index were good . Reliability of the subscales varied from good ( bias ) to poor ( external validity ) . The Quality Index correlated highly with an existing , established instrument for assessing r and omised studies ( r 0.90 ) . There was little difference between its performance with non-r and omised and with r and omised studies . Raters took about 20 minutes to assess each paper ( range 10 to 45 minutes ) . CONCLUSIONS : This study has shown that it is feasible to develop a checklist that can be used to assess the method ological quality not only of r and omised controlled trials but also non-r and omised studies . It has also shown that it is possible to produce a checklist that provides a profile of the paper , alerting review ers to its particular method ological strengths and weaknesses . Further work is required to improve the checklist and the training of raters in the assessment of external validity The aim of this study was to evaluate the short-term benefits of a pulmonary rehabilitation program in chronic obstructive pulmonary disease ( COPD ) patients . The study was a r and omized controlled trial that included 54 mild and moderate COPD patients . Patients were assigned to either an 8-week-long pulmonary rehabilitation program , which consisted of exercise plus education ( rehabilitation group ) , or were controls . All the patients were evaluated at baseline at the completion of the 8th week of the program and one month after the completion of the pulmonary rehabilitation program using five instruments : arterial blood gas analysis , postbronchodilator pulmonary function test , 6-minute walk test ( 6MWT ) , Saint George Respiratory Question naire ( SGRQ ) , and the dyspnea visual analog scale ( VAS ) There were no statistically significant differences in the pulmonary functions and pulmonary gas analysis between baseline , discharge ( 8th week ) , and the 12th-week visit in both groups ( p > 0.05 ) . Rehabilitation result ed in significant improvements in both the VAS and the 6MWT at the 8th week , but by the 12th week all of these improvements had deteriorated . All of the SGRQ domains improved both at the 8th and the 12th week , with a significant difference between the groups ( p < 0.05 ) . We conclude that rehabilitation result ed in improvements in exercise capacity , health status , and dyspnea . All of these benefits , however , tend to deteriorate in the first month after rehabilitation . Therefore , it is strongly recommended that all patients with COPD be kept motivated in order to continue with rehabilitation and maintain the benefits gained UNLABELLED The central purpose of pulmonary rehabilitation is to reduce morbidity by improving functional capacity through exercise . It is still unknown if improvements in functional capacity are maintained in the long-term and if this leads to increased physical activity levels as measured by a free-living activity monitor . The hypothesis of this study was that pulmonary rehabilitation would lead to a sustained increase in st and ard outcome measures and in daily physical activity . METHODS A prospect i ve study of 47 subjects with COPD was performed , registered at Clinical Trials.gov ( Clinical Trial Number NCT 0112943 ) . The primary outcome was a maintained improvement in st and ard outcome measures with a secondary aim of an increase in daily physical activity . A convenient sample of the cohort ( n = 17 ) was re-evaluated at a third time point at 1 year . RESULTS A seven week hospital based outpatient pulmonary rehabilitation program led to a significant reduction in total energy expenditure ( p < 0.044 ) and breathlessness ( Borg , p < 0.011 ) and improved exercise capacity ( ISWT , p > 0.001 , 6MWT , p > 0.002 ) PiMax ( p > 0.007 ) and quality of life scores ( SGRQ , p > 0.001 , EQ5D , 0.025 ) . However , pulmonary rehabilitation did not significantly change the average number of daily steps taken , time spent sedentary activity , METs consumed or daily physical activity . Indeed , all of the st and ard and freeliving values had returned towards the baseline value at 1 year . DISCUSSION These findings show that while pulmonary rehabilitation increased exercise capacity this was not transmitted into increased daily physical activity . Hence , alternative methods to alter/affect behavioural change need to be addressed OBJECTIVE To establish the minimal important difference ( MID ) for the six-minute walk distance ( 6MWD ) in persons with chronic obstructive pulmonary disease ( COPD ) . DESIGN Analysis of data from an observational study using distribution- and anchor-based methods to determine the MID in 6MWD . SETTING Outpatient pulmonary rehabilitation program at 2 teaching hospitals . PARTICIPANTS Seventy-five patients with COPD ( 44 men ) in a stable clinical state with mean age 70 years ( SD 9 y ) , forced expiratory volume in one second 52 % ( SD 21 % ) predicted and baseline walking distance 359 meters ( SD 104 m ) . INTERVENTIONS Not applicable . MAIN OUTCOME MEASURES Participants completed the  six-minute walk test  before and after a 7-week pulmonary rehabilitation program . Participants and clinicians completed a global rating of change score while blinded to the change in 6MWD . RESULTS The mean change in 6MWD in participants who reported themselves to be unchanged was 17.7 meters , compared with 60.2 meters in those who reported small change and 78.4 meters in those who reported substantial change ( P=.004 ) . Anchor-based methods identified an MID of 25 meters ( 95 % confidence 
    Output:
    
Reported relationships were facilitated by healthcare professionals , social supporters , motivation and encouragement , reduced fear and seeing benefits and hindered by changing physical health , environment , lack of motivation , fear and social isolation .
The associations between increased levels of PA and quality of life , respiratory function and dyspnoea are largely based on 6MWD and PA question naires .
Initial benefits from PR decline after program completion .
Following PR , increased levels of physical activity in people with COPD undertaking exercise maintenance programmes are positively related with improvements in exercise capacity , quality of life and dyspnoea .