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 .
Interpreting quality-of-life clinical trial data for use in the clinical practice of antihypertensive therapy.
The use of  quality -of-life indices  in therapeutic trials is gaining recognition as important outcome variables for evaluating the total impact of antihypertensive therapy . While the statistical significance of treatment differentials in  quality -of-life indices  has been well documented , their clinical relevance still remains unclear . The interpretation of clinical trial quality -of-life treatment differentials depends on a clear underst and ing of the normal variability in the index due to changes in day-to-day living and the relationship between the size of the differential and shifts in population responses . Using the results from a large-scale r and omized clinical trial on  quality of life  and  antihypertensive therapy  , a rationale for the interpretation of clinical trial results for use by the practicing clinician is presented
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 .