Reliability and validity of the Impact of Event Scale (IES): version for Brazilian burn victims

The aims of this study were to assess the internal reliability (internal consistency), construct validity, sensitivity and ceiling and floor effects of the Brazilian-Portuguese version of the Impact of Event Scale (IES).

Methodological research design.

The Brazilian-Portuguese version of the IES was applied to a group of 91 burned patients at three times: the first week after the burn injury (time one), between the fourth and the sixth months (time two) and between the ninth and the 12th months (time three). The internal consistency, construct validity (convergent and dimensionality), sensitivity and ceiling and floor effects were tested.

Cronbach's alpha coefficients showed high internal consistency for the total scale (0·87) and for the domains intrusive thoughts (0·87) and avoidance responses (0·76). During the hospitalisation (time one), the scale showed low and positive correlations with pain measures immediately before (r=0·22; p<0·05) and immediately after baths and dressings (r=0·21; p<0·05). After the discharge, we found strong and negative correlations with self-esteem (r=-0·52; p<0·01), strong and positive with depression (r=0·63; p<0·01) and low and negative with the Bodily pain (r=-0·24; p<0·05), Social functioning (r=-0·34; p<0·01) and Mental health (r=-0·27; p<0·05) domains of the SF-36 at time two. Regarding the sensitivity, no statistically significant differences were observed between mean scale scores according to burned body surface (p=0·21). The floor effect was observed in most of the IES items.

The adapted version of the scale showed to be reliable and valid to assess postburn reactions on the impact of the event in the group of patients under analysis.

The Impact of Event Scale can be used in research and clinical practice to assess nursing interventions aimed at decreasing stress during rehabilitation.