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Table 3 The use of imputed values in CopenHeart VR

From: Effect of comprehensive cardiac rehabilitation after heart valve surgery (CopenHeartVR): study protocol for a randomised clinical trial

Observed pattern in group B at 1, 4 and 6 months Imputed value in group B at 1 month Imputed value in group B at 4 month Imputed value in group B at 6 months
misa, mis, mis X1-barb X4-barc X6-bard
mis, mis, Y3e Y3 - (deltaf + delta2g)h Y3 - delta2  
mis, Y2, mis Y2 – delta1   Y2 + delta2
Y1, mis, mis   Y1 + delta1 Y1 + delta1 + delta2
Y1, Y2, mis    Y2 + delta2
Y1, mis, Y3   (Y1 + delta1 + Y3 -delta2)/2  
mis, Y2, Y3 Y2 - delta1   
  1. Table to explain the use of imputing quantities derived from observed values in a group (group A) to impute missing values in a group (group B).
  2. aThe value at 4 months is missing in group B.
  3. bMean of values observed in group A at 1 month.
  4. cMean of values observed in group A at 4 months.
  5. dMean of values observed in group A at 6 months.
  6. eObserved value in group B at 6 months.
  7. fThe mean of difference between values observed at 4 months and value observed at 1 month in group A.
  8. gThe mean of difference between value observed at time 6 months and value observed at time 4 months in group A.
  9. hIf an imputed value is 0 it is set equal to 0.
  10. Mis, Missing value; X1, Value at month 1; X4, Value at month 4; X6, Value at month 6.