Bioequivalence and Bioavailability Forum • a bit corrected workaround

a bit corrected workaround [RSABE / ABEL]

posted by mittyri – Russia, 2023-07-08 00:52 (684 d 19:59 ago) – Posting: # 23663
Views: 4,231

Hi Helmut!

❝ if (ds == "per4full") {

❝ # now the equivalent of SAS code for R-R, dlat analysis

❝ m2 <- lm(RR ~ seq, data = data_r)

❝ dfRR <- m2$df.residual

❝ s2wR <- summary(m2)$sigma^2 / 2

❝ } else {

❝ # workaround because lm() with only one sequence not possible

❝ # make a column with intra-subject variances

❝ for (i in 1:nrow(data_r)) {

❝ data_r$varR[i] <- var(c(data_r$logpk.R1[i],

❝ data_r$logpk.R2[i]), na.rm = TRUE)

❝ }

❝ dfRR <- nrow(data_r) - 2

❝ s2wR <- mean(data_r$varR)

❝ }

I suggest to substitute the workaround to dinosaur method:


  sumsq <- 0

  for (Seq in unique(data_r$seq)) {

    CurrentData <- data_r$RR[data_r$seq == Seq]


    sumsq <- sumsq + sum((CurrentData-mean(CurrentData))^2)

  }

  NSeqs <- length(unique(data_r$seq))

  s2wR    <- sumsq/2/(nrow(data_r) - NSeqs)  

  dfRR    <- nrow(data_r) - NSeqs

at least it gives exactly the same results as classical one.
Yes, ABE is still under fire, the best approach you've found is here

Sorry, right now don't have a clue regarding differences with Winnonlin in RSABE part

—
Kind regards,
Mittyri

Complete thread:

any SAS or R-macro for 3 period two sequence RSABEIs Achievwin 2023-07-05 18:38 [RSABE / ABEL]
- Use the one for TRTR | RTRT Helmut 2023-07-06 08:46
  - RSABE R coded by Detlew mittyri 2023-07-06 14:07
    - ‘dlat’ for 3-period full replicate? Helmut 2023-07-07 14:41
      - ‘dlat’ for 3-period full replicate? mittyri 2023-07-07 16:04
        
        Likely wrong workaround? Helmut 2023-07-07 20:06
        
        a bit corrected workaroundmittyri 2023-07-07 22:52
        
        THX! Another attempt… Helmut 2023-07-08 12:15
        
        complete.cases for dlat and ilat? mittyri 2023-07-09 21:45
        
        a bit corrected workaround Achievwin 2023-07-10 20:43