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Table 1 Summary of the 20 randomised controlled trials

From: Sample size estimation for randomised controlled trials with repeated assessment of patient-reported outcomes: what correlation between baseline and follow-up outcomes should we assume?

  Trial name Trial population Age range (years) Outcome measures No. of outcomes Time points post-randomisation No. of time points No. of correlations Sample size at baseline Max Na Reference Year of publication
1 Leg Ulcer Leg ulcers 32 to 97 EQ-5D, SF-36 9 3, 12 months 2 18 233 200 [9] 1998
2 NAMEIT Early severe rheumatoid arthritis 18 to 75 SF-36, SF-6D 9 2, 4, 6, 8, 10, 12 months 6 54 222 222 [10] 2000
3 Homeopathy for CFS Chronic fatigue syndrome (CFS) 20 to 62 MFI 5 6 months 1 5 103 85 [11] 2004
4 Acupuncture Low back pain 20 to 64 SF-36 8 3, 12, 24 months 3 24 239 217 [12] 2005
5 Knee Replacement Osteoarthritis patients undergoing total knee replacement 51 to 92 SF-36, WOMAC 14 3 months 1 14 151 114 [13] 2005
6 FED Older (aged ≥ 65) hospitalised patients with acute illness 65 to 93 Barthel, SF-36 9 1.5, 6 months 2 18 445 225 [14] 2006
7 AIM-High Malignant melanoma 18 to 77 EORTC QLQ-C30 15 6, 12, 18, 24 months 4 60 444 392 [15] 2006
8 PoNDER New mothers 18 to 45 CORE-OM, EPDS,b SF-36, SF-6D 9 4.5, 10.5, 16.5 months 3 26 2659 2659 [16] 2009
9 COPD Chronic obstructive pulmonary disease (COPD) 49 to 86 EQ-5D, SF-36, SF-6D 12 2, 6, 12, 18 months 4 48 238 172 [17] 2010
10 Corn Plasters Foot corns 18 to 90 EQ-5D, EQ-5D VAS, VAS Pain 3 3, 6, 9, 12 months 4 12 201 182 [18] 2013
11 PLINY Independently living older people (aged ≥ 75) 75 to 95 EQ-5D, EQ-5D VAS, GSES, ONS Well-being, PHQ-9, SF-36 15 6 months 1 15 157 56 [19] 2014
12 3Mg Adults with acute severe asthma in the emergency department 16 to 88 EQ-5D 1 1 month 1 1 932 437 [20] 2014
13 SELF Shoulder rotator cuff tendinopathy 23 to 83 SPADI 3 3, 6, 12 months 3 9 85 59 [6] 2016
14 BEADS Post-stroke depression 31 to 97 EQ-5D, EQ-5D VAS, PHQ-9 3 6 months 1 3 49 39 [21] 2016
15 DiPALS Amyotrophic lateral sclerosis (ALS) 23 to 83 EQ-5D, SAQLI, SF-36 13 2, 3, 6, 9, 12 months 5 65 74 55 [22] 2016
16 Lifestyle Matters Independently living older people (aged ≥ 65) 65 to 92 EQ-5D, EQ-5D VAS, GSES, PHQ-9, SF-36 14 6, 24 months 2 28 288 262 [23] 2017
17 IPSU Women with urinary incontinence and sexual dysfunction 21 to 70 EQ-5D, PISQ-31, SF-36 15 6 months 1 15 107 66 [24] 2018
18 POLAR Lumbar radicular syndrome (LRS) 23 to 71 Back Pain VAS, EQ-5D, EQ-5D VAS, Leg Pain VAS, ODI 5 1.5, 3, 6 months 3 15 80 73 [25] 2018
19 PRACTICE COPD 40 to 92 EQ-5D, EQ-5D VAS 2 0.25, 1, 3 months 3 6 55 42 [26] 2018
20 STEPWISE Schizophrenia 18 to 71 B-IPQ, BPRS, EQ-5D, EQ-5D VAS, PHQ-9, RAND SF-36 14 3, 12 months 2 28 412 358 [27] 2018
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  1. aMax N is the maximum sample size for the baseline and post-randomisation follow-up correlations
  2. bFor the PoNDER trial the EPDS was measured at baseline and at 4.5 and 10.5 months post-randomisation
  3. Abbreviations: Barthel Barthel Index for Activities of Daily Living (ADL), B-IPQ Brief Illness Perception Questionnaire, BPRS Brief Psychiatric Rating Scale, CORE-OM Clinical Outcomes in Routine Evaluation-Outcome Measure, EORTC QLQ European Organisation for Research and Treatment of Cancer Quality of Life Questionnaire, EPDS Edinburgh Postnatal Depression Scale, EQ-5D EuroQol Five Dimension, GSES General Self-Efficacy Scale, MFI Multidimensional Fatigue Inventory, ODI Oswestry Disability Index, ONS Office for National Statistics Well-being Questionnaire, PHQ-9 Patient Health Questionnaire, PISQ-31 Pelvic Organ Prolapse/Urinary Incontinence Sexual Questionnaire, RAND SF-36 Research and Development 36-item Short Form Survey Instrument, SAQLI Sleep Apnea Quality of Life Index, SF-36 Short Form (36 item) Health Survey, SF-6D Short Form Six Dimension, SPADI Shoulder Pain and Disability Index, VAS visual analogue scale, WOMAC Western Ontario and McMaster Universities Osteoarthritis Index