The Association Between Performance Status and Health-Related Quality of Life

Abstract

Background: Performance Status (PS) is often used to assess the functional status of cancer patients. One of the most commonly used scales is the Eastern Cooperative Oncology Group (ECOG) PS. Using the ECOG PS scale, the oncologist assigns a score ranging from 0 (Fully active, able to carry on all pre-disease performance without restriction) to 4 (completely disabled; cannot carry on any selfcare; totally confined to bed or chair). In multiple myeloma (MM), a PS > 2 has been associated with a 35% increased risk of death following autologous stem cell transplant (ASCT) (Turesson et al, Br J Haematol, 1999), and therefore a PS ≤ 2 is generally required for ASCT and for eligibility in clinical trials.PS is often seen as a surrogate for health-related quality of life (HRQOL), which are patient reported measure(s) of well-being; however, they are separate constructs. While poorer PS has been associated with a decrease in HRQOL, it is unclear how much of the variance in HRQOL is explained by PS.Objectives: 1) To determine the association between PS and HRQOL; 2) to determine how much variance in HRQOL is explained by PS.Methods: Data was extracted from the open-access Multiple Myeloma Research Foundation (MMRF) Researcher Gateway corresponding with interim analysis 6 from the CoMMpass study. The CoMMpass study dataset included 562 patients who completed the EORTC QLQ-C30 and EORTC QLQ-MY20 at MM diagnosis. The range of scores for these HRQOL measures is 0-100, with higher scores indicating higher values. Data was analyzed using SPSS 21. The association between PS and HRQOL was assessed by one-way ANOVA tests; the amount of variance in HRQOL explained by PS was assessed by linear regression modeling.Results: PS was associated with all 9 HRQOL scales analyzed (p<0.001). Poorer PS was associated with poorer global health, physical function, emotional functioning, cognitive functioning, social functioning, and role functioning; and greater disease symptoms, fatigue, and pain. However, PS explained only a portion of the variance seen with each scale. The most variance explained by PS was seen in the physical functioning scale (38%); the least was in the cognitive functioning scale (10%). Adding age and International Staging System (ISS) stage significantly improved 4 of the 9 models (physical functioning, emotional functioning, fatigue, and pain); however, improvements were modest (2-5%).Conclusions: PS was significantly associated with HRQOL but it was not considered a good explanatory model for any of the scales analyzed as it could not explain at least 50% of the variance, even after the addition of age and ISS stage. A broader examination of the patients' disease, functional, social, and socioeconomic context is needed to better understand HRQOL and to identify areas which may be improved by intervention.Table 1Association between Performance Status and Health-Related Quality of LifePerformance Status 0 n= 202Performance Status 1 n = 249Performance Status 2 n = 47Performance Status 3/4 n = 29pGlobal Health Scale75543321<0.001Physical Functioning Scale93733313<0.001Cognitive Functioning Scale100838366<0.001Emotional Functioning Scale83756641<0.001Social Functioning Scale100663333<0.001Role Functioning Scale1006600<0.001Disease Symptom Scale16275053<0.001Fatigue Scale22336677<0.001Pain Scale163383100<0.001Table 2Amount of Variance in Health-Related Quality of Life Explained by Performance Status, Age, and StageModel 1AModel 2BR2FpR2F changepCGlobal Health Scale0.23335.7<0.0010.2341.60.188Physical Functioning Scale0.38172.0<0.0010.4056.3<0.001Cognitive Functioning Scale0.10513.8<0.0010.1211.30.259Emotional Functioning Scale0.10213.3<0.0010.15810.1<0.001Social Functioning Scale0.21532.1<0.0010.2222.10.106Role Functioning Scale0.29548.7<0.0010.2970.70.563Disease Symptom Scale0.14819.9<0.0010.1641.90.132Fatigue Scale0.23535.9<0.0010.2595.90.001Pain Scale0.20430.0<0.0010.2182.70.048A-Performance statusB-Performance status, age, and International Staging System stageC-Of F change DisclosuresVij:Takeda, Onyx: Research Funding; Celgene, Onyx, Takeda, Novartis, BMS, Sanofi, Janssen, Merck: Consultancy.