Our review revealed a great heterogeneity in definition , format , and values of what is considered a clinical ly relevant difference in pain in RCTs of analgesics , and st and ardizations are advisable
OBJECTIVE To describe the  pain decrease considered as clinical ly relevant when design ing a trial and reporting its results .
Characterizing individual differences in heat-pain sensitivity
Abstract Heat induced pain has been shown to follow a positively accelerating power function for groups of subjects , yet the extent to which this applies to individual subjects is unknown . Statistical methods were developed for assessing the goodness of fit and reliability of the power function for data from individual subjects with the aim of using such functions for characterizing individual differences in heat‐pain sensitivity . 175 subjects rated ascending and r and om series of contact heat stimuli  with visual analogue scales for pain intensity ( VAS‐I ) and unpleasantness ( VAS‐A ) . Curve fitting showed excellent model fit . Substitution of model estimates in place of observed VAS scores produced minimal bias in group means , about 0.3 VAS units in the ascending series and 1.0 in the r and om series , on a 0–100 scale . Individual power function exponents were considerably higher for the ascending than for the r and om series and somewhat higher for VAS‐A than for VAS‐I ( means : ascending VAS‐I=9.04 , VAS‐A=9.80 ; r and om VAS‐I=4.95 , VAS‐A=5.67 ) . The reliability of VAS estimates was high ( ≧.93 ) , and for the ascending series it remained so when extrapolating 4 ° C beyond the empirical range . Exponent reliability was high for the ascending series ( VAS‐I=.92 ; VAS‐A=.91 ) , but considerably lower for the r and om series ( VAS‐I=.69 ; VAS‐A=.71 ) . Individual differences constituted 60 % of the total variance in pain ratings , whereas stimulus temperature accounted for only 40 % . This finding underscores the importance of taking individual differences into account when performing pain studies
Our review revealed a great heterogeneity in definition , format , and values of what is considered a clinical ly relevant difference in pain in RCTs of analgesics , and st and ardizations are advisable
OBJECTIVE To describe the  pain decrease considered as clinical ly relevant when design ing a trial and reporting its results .