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Table 4 Internal consistency reliability and clinical and concurrent validity of the FACT-M and MCC-specific scores in the mMCC population

From: Psychometric properties of the FACT-M questionnaire in patients with Merkel cell carcinoma

FACT-M Subscales and Summary scores # of items Cronbach’s alphaa Scale structure ECOG PS (mean [SD]) EQ-5D VAS EQ-5D index
Range of item-subscale correlationsb Convergentc/ Divergentd validity (% of items) 0 (N = 39) 1 (N = 31) p-valuee Correlationb Correlationb
FACT-G subscales
 Physical well-being (PWB) 7 0.86 0.49–0.81 100/57 23.21 (5.02) 20.10 (6.08) 0.0221 0.44 0.75
 Social/Family well-being (SWB) 7 0.81 0.41–0.86 100/71 23.03 (4.78) 21.49 (5.30) 0.2065 0.15 0.24
 Emotional well-being (EWB) 6 0.83 0.53–0.75 100/67 17.97 (4.22) 16.87 (4.95) 0.3179 0.32 0.53
 Functional well-being (FWB) 7 0.87 0.49–0.82 100/71 17.41 (6.68) 15.48 (5.90) 0.2113 0.29 0.63
Melanoma-specific subscales
 Melanoma Subscale (MS) 16 0.85 0.24–0.85 75/31 51.64 (8.93) 49.10 (9.02) 0.2427 0.39 0.75
 Melanoma surgery Scale (MSS) 8 0.84 0.15–0.81 88/63 26.51 (6.19) 25.58 (6.03) 0.5290 0.16 0.51
Summary scales
 FACT-M TOI 30 0.94 92.26 (18.75) 84.68 (19.40) 0.1026 0.41 0.78
 FACT-G total score 27 0.94 81.62 (17.25) 73.95 (17.62) 0.0713 0.37 0.67
 FACT-M total score 43 0.96 133.26 (24.66) 123.04 (25.21) 0.0926 0.40 0.74
MCC-specific scores
 Physical Function score (PF) 6 0.88 16.38 (5.67) 13.71 (5.54) 0.0519 0.37 0.72
 Psychological Impact score (PI) 6 0.85 17.82 (4.40) 16.87 (5.18) 0.4101 0.30 0.52
 MCC summary score 12 0.91 34.21 (8.99) 30.58 (9.94) 0.1145 0.37 0.69
  1. # number, ECOG PS Eastern Cooperative Oncology Group performance status, MCC Merkel cell carcinoma, PAS PRO analysis set, SD standard deviation, TOI Trial Outcome Index
  2. aRecommended threshold α > 0.7; bPearson correlation coefficients; c% of items correlated with its own dimension ≥0.4; d% of items correlated with its own dimension higher than the correlation with any other dimension; e p-value from t-test of score between the two ECOG PS groups at baseline
  3. Internal consistency reliability and clinical validity were assessed in the PAS (N = 70)
  4. ECOG PS: 0 = fully active; 1 = restricted in physically strenuous activity