Proxy-ratings versus self-ratings in assessing the quality of life of women with gynecological cancer

This study set out to answer two questions. First, how do the quality of life (QOL) assessments that patients give about themselves compare with the assessments made on their behalf by health professionals and by family or other informal caregivers? Second, how closely do those proxy judgments actually match what patients report? The research team behind the work was Elfriede Greimel, F. Peintinger, I. Cegnar, E. Pongratz, and Irene Thiel.

The sample came from 262 women who had recently been diagnosed with cervical, ovarian, endometrial, or breast cancer, and the ratings were gathered as their illness progressed. Gynecological oncologists, nurses, and psychologists acted as proxy raters, and for each patient an informal caregiver did the same. Everyone used the QOL-Index, a short standardized questionnaire covering five areas: activity, daily living, health, support, and outlook, along with a global rating of quality of life.

Each rater filled out the questionnaire separately, with no reference to the others, at four points in the process. The first was before treatment, the second after treatment, then again at the six-month follow-up, and finally at one year.

For the most part, the average scores from proxy raters landed near the patients' own scores, though some gaps showed up. In the period around treatment, both before and after, health professionals leaned toward rating patients' activity and daily living more favorably than the patients themselves did. By the one-year mark the physicians' ratings came out significantly higher than patient ratings across every area measured, daily living being the one exception.

Exact agreement between patient and proxy was uneven at the earlier assessments, falling anywhere from 20% to 89% before and after treatment. Later on it tightened considerably: at six months and one year, the share of exact matches rose on all subscales, reaching somewhere between 66% and 95%.

Of all the proxy raters, the informal caregivers tracked patients most closely. Their intraclass correlation coefficients with patient ratings ran from .54 to .85, the highest agreement found in the study. The takeaway is that people close to the patient produced the nearest substitute for the patient's own voice, while using health professionals' answers in place of patient answers calls for some caution.