Do external factors such as weather affect patient reported outcomes of patients with malignant diseases?

Abstract

e18715 Background: The QLQ-C30 is one of the most widely used patient-reported outcome (PRO) instrument to assess health-related quality of life in cancer patients developed by the European Organization for Research and Treatment of Cancer (EORTC). Even if only little scientific evidence is published on this topic, patients often report that their emotional and physical state varies depending on climatic conditions. To enhance the understanding of quality of life in cancer patients, this study analyzed whether external factors like weather data and season can influence PRO measures and cancer patients’ well-being. Methods: Over a period of 12 months data was obtained from inpatient and outpatient cancer patients in two German cancer centers using the QLQ-C30. Items were assigned to five functional scales, three symptom scales, a global health status/QoL scale, and a number of single items assessing symptoms commonly reported by cancer patients.Patients were approached by their medical oncologist or nursing staff to complete the questionnaire anonymously once or multiple times. QoL data were linked to weather factors including temperature, hours of sunshine and season. Results: We received a total of n = 5040 responses (54 % male). Regarding global health status/QoL, the best result was recorded at 25 - 30 degrees, and the lowest value was measured at 5 - 10 degrees (mean 61.3 vs. 52.6, p < 0.001). Insomnia was most pronounced at < = 0 degrees and least present at 25 – 30 degrees (mean 39.3 vs. 29.5, p < 0.001). Overall, best scores were obtained at 25 – 30 degrees, whereas quality of life and symptom burden were worst at 5 – 10 degrees. Global health/QoL was highest at 8 hours of sunshine and lowest at 0 hours of sunshine (mean 56.9 vs. 50.9, p .003). Global health/QoL was lower in winter months than in summer (mean 53.8 vs. 57.4, p < 0.001) presenting highest scores in June and July. Conclusions: The findings of our study indicate that quality of life in cancer patients as well as PROs can be influenced systematically by external factors like season or weather conditions. This could possibly also be of importance when interpreting the results of studies that use standardized instruments to assess health-related quality of life in cancer patients -e.g., if the questionnaires were only answered in certain month (summer/winter) or under external conditions that were not evenly distributed.