BE parallel design [General Statistics]
Dear PKPDPKPD!
See my first post. You should only transform the calculated PK parameters (not the concentrations).
Let's misuse Helmut's data (download here)
Although his data are from a cross-over study, we will use only period 1.
83.657% (63.514% - 110.189%)
I checked the 'manual' calculation in WinNonlin and EquivTest:
WinNonlin: 83.6572% (63.5100% - 110.1958%)
EquivTest: 83.66% (63.51% - 110.18%)
Slight differences seen in results are not uncommon...
❝ Should AUC and Cmax be also calculated from the log transformed data?
See my first post. You should only transform the calculated PK parameters (not the concentrations).
- Calculate AUC from your analytical results by any method you like (trapezoidal rule preferred, but not limited to).
- Cmax is simply the highest measured concentration.
- For the comparison you log-transform AUC and Cmax.
Let's misuse Helmut's data (download here)
Although his data are from a cross-over study, we will use only period 1.
- Change the header of the first column from 'Seq' to 'Trt'
- Delete the column 'Rand'
- Delete the column 'P2'
- log-transform 'P1'
- calculate separately for each treatment:
- arithmetic mean: (1: 3.56227, 2: 3.38383)
- exp(arithmetic mean): (1: 35.24321, 2: 29.48349),
- note: these are the geometric means of untransformed data!
- standard deviations: (1: 0.35950, 2: 0.42377)
- variances = SD²: (1: 0.12924, 2: 0.17958)
- n1,2 (group sizes): (1: 12, 2: 12)
- Q1,2 = variance × (n1,2-1): (1: 1.42165, 2: 1.97539)
- arithmetic mean: (1: 3.56227, 2: 3.38383)
- calculate
R = sqrt[(n1+n2)/(n1×n2)×(Q1+Q2)/(n1+n2-2)]
: 0.16042
- look up the critical value of the t-distribution for alpha=0.05 with n1+n2-2 degrees of freedom: t 1.71714
- calculate t × R: 0.27547
- calculate Delta (difference of means Trt 2 - Trt 1): -0.17844
- antilog Delta (= point estimate): 0.83657
- calculate lower/upper 90% confidence limit = Delta ± t × R: lo: -0.45391, hi: 0.09702
- antilog lo and hi: exp(lo): 0.63514, exp(hi): 1.10189
83.657% (63.514% - 110.189%)
I checked the 'manual' calculation in WinNonlin and EquivTest:
WinNonlin: 83.6572% (63.5100% - 110.1958%)
EquivTest: 83.66% (63.51% - 110.18%)
Slight differences seen in results are not uncommon...
—
Regards, Jaime
Regards, Jaime
Complete thread:
- BE parallel design pkpdpkpd 2007-04-03 17:45 [General Statistics]
- BE parallel design Jaime_R 2007-04-03 18:58
- BE parallel design pkpdpkpd 2007-04-03 19:07
- BE parallel design Jaime_R 2007-04-03 19:41
- BE parallel design pkpdpkpd 2007-04-03 20:14
- BE parallel design Jaime_R 2007-04-03 20:29
- BE parallel design pkpdpkpd 2007-04-03 21:48
- BE parallel designJaime_R 2007-04-04 15:14
- BE parallel design Helmut 2007-04-04 15:31
- BE parallel design pkpdpkpd 2007-04-04 17:32
- BE parallel design Jaime_R 2007-04-04 20:33
- BE parallel design Sathya 2008-09-01 07:21
- BE parallel design Sathya 2008-09-04 12:37
- BE parallel design Helmut 2007-04-04 15:31
- BE parallel designJaime_R 2007-04-04 15:14
- BE parallel design pkpdpkpd 2007-04-03 21:48
- BE parallel design Jaime_R 2007-04-03 20:29
- BE parallel design pkpdpkpd 2007-04-03 20:14
- BE parallel design Jaime_R 2007-04-03 19:41
- BE parallel design pkpdpkpd 2007-04-03 19:07
- BE parallel design Jaime_R 2007-04-03 18:58