Variables | Instrument | Subscales | Cronbach’s alpha | Hypothesised difference (anticipated power) |
---|---|---|---|---|
Health status | Medical Outcome Study Short Form 12 (SF-12) | Physical Component Summary (PCS) [0–100] Mental Component Summary (MCS) [0–100] | 0.87 0.84 | 2.4 (97%) 8.21(100%) |
Anxiety—depression | Hospital Anxiety and Depression Scale (HADS)41 42 | HADS-A scale [0–21] HADS-D scale [0–21] | 0.83 0.82 | 1.26 (86%) 4.3 (100%) |
Quality of life | HeartQol questionnaire43 57 | The emotional subscales [0–3] The global subscales [0–3] | 0.80–0.91 0.80–0.91 | 0.3 (85%) 0.2 (95%) |
Sleep | Pittsburgh Sleep Quality Index (PSQI)58 | Component 1: Subjective sleep quality score [0–3] Component 2: Sleep latency score [0–3] Component 3: Sleep duration score [0–3] Component 4: Habitual sleep efficiency score [0–3] Component 5: Step disturbances score[0–3] Component 6: Use of sleeping medication score[0–3] Component 7: Daytime dysfunction score [0–3] Global PQSI score [0–21] | 0.83 | 2.2 (96%) |
Pain | Örebro Musculoskeletal Pain Questionnaire (OMPQ)44 | OMPQ total score [0–210] | 0.86 | 10.2 (98%) |
Strength and endurance in legs | Sit-to-stand test39 | Total number of repetitions | NR | 3.6 (100%) |
HADS, Hospital Anxiety and Depression Scale; NR, not reported.