The Association Between Performance Status and Health-Related Quality of Life
Authors: Fiala Mark A , Keller Jesse , Slade Michael , Stockerl-Goldstein Keith , Tomasson Michael , Vij Ravi , Wildes Tanya M 
Published: October 2019

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 1. Association between Performance Status and Health-Related Quality of Life Performance Status 0 n= 202 Performance Status 1 n = 249 Performance Status 2 n = 47 Performance Status 3/4 n = 29 p Global Health Scale 75 54 33 21 <0.001 Physical Functioning Scale 93 73 33 13 <0.001 Cognitive Functioning Scale 100 83 83 66 <0.001 Emotional Functioning Scale 83 75 66 41 <0.001 Social Functioning Scale 100 66 33 33 <0.001 Role Functioning Scale 100 66 0 0 <0.001 Disease Symptom Scale 16 27 50 53 <0.001 Fatigue Scale 22 33 66 77 <0.001 Pain Scale 16 33 83 100 <0.001
Table 2. Amount of Variance in Health-Related Quality of Life Explained by Performance Status, Age, and Stage Model 1A Model 2B R2 F p R2 F change pC Global Health Scale 0.233 35.7 <0.001 0.234 1.6 0.188 Physical Functioning Scale 0.381 72.0 <0.001 0.405 6.3 <0.001 Cognitive Functioning Scale 0.105 13.8 <0.001 0.121 1.3 0.259 Emotional Functioning Scale 0.102 13.3 <0.001 0.158 10.1 <0.001 Social Functioning Scale 0.215 32.1 <0.001 0.222 2.1 0.106 Role Functioning Scale 0.295 48.7 <0.001 0.297 0.7 0.563 Disease Symptom Scale 0.148 19.9 <0.001 0.164 1.9 0.132 Fatigue Scale 0.235 35.9 <0.001 0.259 5.9 0.001 Pain Scale 0.204 30.0 <0.001 0.218 2.7 0.048 A-Performance status B-Performance status, age, and International Staging System stage C-Of F change

Disclosures
Vij: Takeda, Onyx: Research Funding; Celgene, Onyx, Takeda, Novartis, BMS, Sanofi, Janssen, Merck: Consultancy.