There was no consistent relationship with factors such as disease-specific or generic instrument or the number of response options .
Negative changes were not associated with larger ESs .
Population -based estimation procedures and brief follow-up were associated with smaller ESs , and acute conditions with larger ESs .
Background .
A number of studies have computed the minimally important difference ( MID ) for health-related quality of life instruments .
To determine whether there is consistency in the magnitude of MID estimates from different instruments .
Long term benefits of rehabilitation at home on quality of life and exercise tolerance in patients with chronic obstructive pulmonary disease.
BACKGROUND --Pulmonary rehabilitation has been shown to have short term subjective and objective benefits for patients with chronic obstructive pulmonary disease ( COPD ) . However , appropriately controlled studies have not previously been performed , nor have the benefits of different types of continuation programme for rehabilitation been investigated . Both these problems have been addressed in a single study of the long term effects of once monthly physiotherapy versus once weekly physiotherapy at home after a comprehensive home rehabilitation programme on quality of life and exercise tolerance in patients with COPD . METHODS --Thirty six patients with severe airways obstruction ( mean SD ) forced expiratory volume in one second ( FEV1 ) 1.3(0.4 ) 1 , FEV1/inspiratory vital capacity ( IVC ) 37.2(7.9)% ) were studied . Twenty three patients followed a rehabilitation programme at home for 18 months consisting of physiotherapy and supervision by a nurse and general practitioner . During the first three months all 23 patients visited the physiotherapist twice a week for a 0.5 hour session . Thereafter , 11 patients ( group A ) received a session of physiotherapy once weekly while 12 patients ( group B ) received a session of physiotherapy once a month . The control group C ( 13 patients ) received no rehabilitation at all .  Quality of life was assessed by the Chronic Respiratory Question naire , exercise tolerance by the six minute walking distance , and lung function by FEV1 and IVC . Outcome measures were assessed at baseline and at three , six , 12 , and 18 months . RESULTS --Long term improvements in quality of life were found in patients in groups A and B , but not in those in group C compared with baseline , but these only reached significance in group B at all time points . Patients in group B had a higher quality of life than those in group C only at three and 12 months . There was a decrease in both six minute walking distance ( at 12 and 18 months ) and IVC ( at three , 12 , and 18 months ) in patients in group C compared with the baseline measurement . Between groups analysis showed no differences for six minute walking distance , FEV1 , and IVC . CONCLUSIONS --This study is the first to show that rehabilitation at home for three months followed by once monthly physiotherapy sessions improves quality of life over 18 months . The change in quality of life was not associated with a change in exercise tolerance
There was no consistent relationship with factors such as disease-specific or generic instrument or the number of response options .
Negative changes were not associated with larger ESs .
Population -based estimation procedures and brief follow-up were associated with smaller ESs , and acute conditions with larger ESs .
Background .
A number of studies have computed the minimally important difference ( MID ) for health-related quality of life instruments .
To determine whether there is consistency in the magnitude of MID estimates from different instruments .