The ITT-DB population with an LOCF imputation consisted of all patients who received at least one dose of study drug who also had at least one post-randomization assessment for both the ADAS-cog and ADCS-IADL.
We describe the tiers sequentially below: Genome-wide imputation grid (approximately 296K markers): The TxArray's core imputation grid consists of genome-wide approximately 296K SNPs shared in common with the conventional Affymetrix Biobank Array.
It is worth to note the approach based in resampling decision trees under the statistical learning theory, named BINPI-Fusion, where the imputation consist in minimizing the prediction error of the imputed values [ 13].
As there was a considerable number of missing values, especially for the data from the medical examination, it was decided to impute missing data for these variables using chained imputations [ 19] with an imputation model consisting of all the potential predictors as well as the dependent variable.
The imputation method consisted of a) using the Markov chain Monte Carlo method to impute missing data to create a monotonic missing pattern and then b) using a logistic model to complete the imputations.
The imputation model consisted of three variables X1, X2, and the WLE in a fully conditional specification (see van Buuren [2007]) to account for the process that created the missing data.
The multiple imputation procedure consisted of four steps: Fit a Weibull survival model to the original censored survival data.
The multiple imputation procedure consisted of using a regression model fitted for each variable with missing data with 3 imputed data sets [ 52].
The imputation model consisted of the HRQL-scores, physical activity at baseline and 1 year, and age of onset of obesity as predictor and imputation variables, and treatment, gender, age, baseline BMI, marital status, employment, and education as predictor variables.
The imputation model consisted of the height SDS, weight SDS, Body-Mass-Index SDS, age, gender, the height of the other parent, ethnicity, yes or no use of medication influencing growth, and place of attendance of the school doctors.
