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Table 6 Sample sizes required to detect minimum clinically important differences

From: Performance of the SarQoL quality of life tool in a UK population of older people with probable sarcopenia and implications for use in clinical trials: findings from the SarcNet registry

   MCID SD Sample size
80% power, unadjusted 80% power, adjusted 90% power, unadjusted 90% power, adjusted
SarQoL– change in fitness Slight improvement 21 19 26 24 36 34
Any improvement 17 17 32 30 44 42
Slight worsening 1 16 8038 7476 10,760 10,008
SarQoL – change in QoL Slight improvement 5 5 32 30 44 42
Any improvement 9 16 100 94 134 126
Slight worsening 5 12 182 170 244 228
SARC-F – change in fitness Slight improvement 1.0 2.1 140 86 186 114
Any improvement 1.4 1.8 52 32 70 44
Slight worsening 0.3 2.0 1396 852 1868 1140
SARC-F – change in QoL Slight improvement 2.3 1.5 14 10 18 12
Any improvement 0.8 2.5 308 188 412 252
Slight worsening 0.3 2.2 1690 1032 2262 1380
  1. MCID Minimum clinically important difference. Sample size is total sample size for a two arm trial. Calculations assume 1:1 randomisation, alpha 0.05. Adjusted: Sample size multiplied by (1 – r2) where r = 0.27 for correlation between baseline and follow-up SarQoL scores, and r = 0.63 for correlation between baseline and follow-up SARC-F scores. Where calculations deliver odd numbers, sample size is rounded up to nearest even number