Table 1.
Summary of the PRO instruments used in the study
| FKSI | FKSI-DRS | FACT-G | EQ-5D | |
| Objective | Assesses disease-related and treatment-related symptoms in patients with advanced kidney cancer | Assesses disease-related symptoms in patients with advanced kidney cancer | Assesses health-related quality of life for people with cancer. Provides multidimensional, generic measure of well-being and functioning for patients with cancer of any type | Assesses general health status with a simple descriptive profile and a single index value that can be used in the clinical and economic evaluation of health care and population surveys |
| Domains | N/A | N/A (subscale of FKSI) | PWB; SWB; EWB; FWB | Mobility, self-care, usual activity, pain/discomfort, and anxiety/depression |
| Number of items | 15 | 9 | 27 items (34 items in version 4) with five-point Likert scale | 5 (see above) + 1 visual analogue scale thermometer that provides a rating of health from 0 (worst imaginable health state) to 100 (best imaginable health state) |
| Psychometric properties | High internal consistency: Cronbach's α 0.84–0.88; high intraclass correlation (test–retest reliability): 0.90; convergent validity: with FACT-G and FACT-G subscales; discriminant validity: ECOG-PSR; responsiveness to change: GRCS (gender role conflict scale); MID: 3–5 points | High internal consistency: Cronbach's α 0.78; high intraclass correlation (test–retest reliability): 0.85; strong convergent and discriminant validity and responsiveness to change that are similar to those of the FKSI; MID: 2–3 points | High internal consistency: Cronbach's α 0.75–0.92; high test-retest correlation coefficient: 0.82–0.92; concurrent validity: correlation with FLIC (r = 0.79) and QLI (r = 0.74). Construct validity: correlation with mood state: (r = 0.57–0.69); activity level (r = −0.56); social desirability (r = 0.22). Correlation is 0.86 with the FLIC scale, 0.45–0.60 with profile of mood states and also correlated with ECOG-PSR rating; MID: N/A | Test–retest reliability: 0.86–0.90; evidence of construct and discriminant validity. Evidence of concurrent validity with related measures: correlations with health assessment questionnaire (r = 0.46–0.76) and SF-36 (r = 0.52–0.64); MID: N/A |
| Mode | Self-administered (telephone interview) | Self-administered (telephone interview) | Self-administered (telephone interview) | Self-administered, observer, proxy, and telephone |
| Time (minutes) | <10 min | <10 min | 5–10 min | <5 min |
| Languages | English, Chinese, Dutch, French, and 15 other languages | English, Chinese, Dutch, French, and 15 other languages | English, French, Spanish, Koran, and plus 51 other languages | 60 official translations including English, and languages for South Africa, Asia, Europe, Latin America, the Middle East, and Scandinavia |
| Time frame | Past 7 days | Past 7 days | Past 1 week | Current |
PRO, patient-reported outcome; FKSI-DRS, Functional Assessment of Cancer Therapy–Kidney Symptom Index–Disease-Related Symptoms; FACT-G, Functional Assessment of Cancer Therapy-General; EQ-5D, EQ-5D self-report questionnaire; PWB, physical well-being; SWB, social/family well-being; EWB, emotional well-being; FWB, functional well-being; ECOG-PSR: Eastern Cooperative Oncology Group-Performance Status Rating; FLIC, Functional Living Index—Cancer; GRCS, Global Rating of Change Scale; HAQ, health assessment questionnaire; MID, minimal important difference; N/A, not available.