Objective: To determine the level of agreement between patients and observers regarding the frequency with which health-related quality of life topics are discussed during outpatient clinical oncology visits.
Methods: The sample (n=50) consisted of a consecutive series of cancer patients undergoing chemotherapy. Both the patients and observers used a checklist to report which HRQL topics had been discussed during the consultation. Percentage of agreement, kappa and adjust-kappa statistics were calculated.
Results: The percentage agreement between patients' and observers' ratings was generally high, ranging from 74% for fatigue to 96% for sleep problems and cognitive functioning. The average percentage of agreement over the 13 HRQL topics rated was 86%. Cohen's kappa varied between 0.41 (for pain) and 0.78 (for sleep problems). Prevalence-adjusted kappa's were generally higher, ranging from 0.48 (for fatigue) to 0.92 (for sleep problems and social functioning). The average Cohen's kappa and prevalence-adjusted kappa over the 13 HRQL topics were 0.56 and 0.71, respectively. Level of agreement was not found to vary significantly as a function of patients' background characteristics.
Conclusion: Oncology patients' self-reports of the HRQL-related topics discussed during outpatient chemotherapy visits are in reasonably close agreement with those provided by observers.
Practice implications: Our results indicate that the patient is a legitimate source of information about the HRQL-related content of medical encounters, and thus can be used in communication studies where the collection of observational data (e.g., via audio- or videotaping) is either too costly or logistically impractical.