Patient compliance with quality of life questionnaires. Italian Group for Evaluation of Outcomes in Oncology (I.G.E.O.).

AIMS AND BACKGROUND

To evaluate the rate of cancer patients who do not fill out a quality of life (QL) questionnaire, their characteristics and the reasons for not filling out the QL questionnaire.

METHODS

Consecutive cancer patients who were seen in 79 Italian medical oncology and radiotherapy centers over a period of one week were asked to fill out a questionnaire concerning the importance of 46 domains of quality of life, each one scored on 4 levels (not at all, a little, much, and very much).

RESULTS

Of 6,918 cancer patients, 820 (11.9%) did not fill out the questionnaire. The most important reasons for not complying were: illiteracy (17.9%), lack of glasses or poor eye-sight (17.4%), poor physical condition (11.9%), poor psychological condition (5.9%), refusal (28.7%). The questionnaires significantly less filled out were those of older patients with low performance status and educational level or with locally advanced or disseminated disease and inpatients.

CONCLUSIONS

The results of the study reveal the risk of selection bias in QL assessment in randomized controlled trials and suggest the need for more complete information regarding the aim of QL evaluation and the necessity of a proxy's help to overcome the problem, with the awareness that the proxy's influence could modify the response. The impact of the lack of patient compliance on the QL results still remains to be evaluated.