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Here, we’ll go over some examples of using ITT. First we need to load the library before getting in to some sample use cases.

ITT With 5 bootstrap samples

options <- SEQopts(# tells SEQuential to create Kaplan-Meier curves
                   km.curves = TRUE,
                   # tells SEQuential to bootstrap
                   bootstrap = TRUE,
                   # tells SEQuential to run bootstraps 5 times
                   bootstrap.nboot = 5)

# use example data
data <- SEQdata                             
model <- SEQuential(data, id.col = "ID", 
                          time.col = "time", 
                          eligible.col = "eligible", 
                          treatment.col = "tx_init", 
                          outcome.col = "outcome", 
                          time_varying.cols = c("N", "L", "P"), 
                          fixed.cols = "sex",
                          method = "ITT", 
                          options = options)
#> 
#> Full dataset: 12,180 observations, 11 variables
#> 
#> Non-required columns provided, pruning for efficiency
#> 
#> Pruned
#> 
#> Original dataset (eligible subjects): 9,203 observations, 9 variables
#> 
#> Expanding Data...
#> 
#> Pre-filter expansion: 310,080 observations
#> 
#> Expanded dataset: 248,485 observations, 13 variables
#> 
#> Expansion Successful
#> 
#> Final analysis dataset: 248,485 observations, 13 variables
#> 
#> Moving forward with ITT analysis
#> 
#> Bootstrapping with 80% of 300 subjects (240 subjects, ~198,788 observations per resample) 5 times
#> 
#> ITT model created successfully
#> 
#> Creating Survival curves
#> 
#> Completed

km_curve(model, plot.type = "risk")        # retrieve risk plot

risk_data(model)
#> Index: <Followup>
#>    Method Followup      A      Risk   95% LCI   95% UCI         SE
#>    <char>    <num> <char>     <num>     <num>     <num>      <num>
#> 1:    ITT       60      0 0.8372582 0.7646336 0.9098829 0.03705407
#> 2:    ITT       60      1 0.8744359 0.8299662 0.9189056 0.02268902
risk_comparison(model)
#>    Followup    A_x    A_y Risk Ratio RR 95% LCI RR 95% UCI Risk Differerence
#>       <num> <fctr> <fctr>      <num>      <num>      <num>             <num>
#> 1:       60 risk_0 risk_1  1.0444041  0.9685600   1.126187        0.03717768
#> 2:       60 risk_1 risk_0  0.9574838  0.8879519   1.032461       -0.03717768
#>     RD 95% LCI RD 95% UCI
#>          <num>      <num>
#> 1: -0.02814011 0.10249547
#> 2: -0.10249547 0.02814011

ITT with 5 bootstrap samples and losses-to-followup

options <- SEQopts(km.curves = TRUE,               
                   bootstrap = TRUE,                
                   bootstrap.nboot = 5,
                   # tells SEQuential to expect LTFU as the censoring column
                   cense = "LTFU",
                   # tells SEQuential to treat this column as the 
                   # censoring eligibility column
                   cense.eligible = "eligible_cense")

# use example data for LTFU
data <- SEQdata.LTFU
model <- SEQuential(data, id.col = "ID", 
                          time.col = "time", 
                          eligible.col = "eligible", 
                          treatment.col = "tx_init", 
                          outcome.col = "outcome", 
                          time_varying.cols = c("N", "L", "P"), 
                          fixed.cols = "sex",
                          method = "ITT", 
                          options = options)
#> 
#> Full dataset: 54,687 observations, 13 variables
#> 
#> Non-required columns provided, pruning for efficiency
#> 
#> Pruned
#> 
#> Original dataset (eligible subjects): 29,624 observations, 10 variables
#> 
#> Expanding Data...
#> 
#> Pre-filter expansion: 1,609,859 observations
#> 
#> Expanded dataset: 1,119,229 observations, 18 variables
#> 
#> Expansion Successful
#> 
#> Final analysis dataset: 1,119,229 observations, 18 variables
#> 
#> Moving forward with ITT analysis
#> 
#> Bootstrapping with 80% of 1,000 subjects (800 subjects, ~895,383 observations per resample) 5 times
#> 
#> ITT model created successfully
#> 
#> Creating Survival curves
#> 
#> Completed

km_curve(model, plot.type = "risk")

risk_data(model)
#> Index: <Followup>
#>    Method Followup      A       Risk 95% LCI    95% UCI         SE
#>    <char>    <num> <char>      <num>   <num>      <num>      <num>
#> 1:    ITT       60      0 0.02374360       0 0.05930117 0.01814195
#> 2:    ITT       60      1 0.02614576       0 0.05307095 0.01373759
risk_comparison(model)
#>    Followup    A_x    A_y Risk Ratio RR 95% LCI RR 95% UCI Risk Differerence
#>       <num> <fctr> <fctr>      <num>      <num>      <num>             <num>
#> 1:       60 risk_0 risk_1  1.1011710  0.5047355   2.402402       0.002402164
#> 2:       60 risk_1 risk_0  0.9081242  0.4162501   1.981236      -0.002402164
#>      RD 95% LCI  RD 95% UCI
#>           <num>       <num>
#> 1: -0.009778824 0.014583152
#> 2: -0.014583152 0.009778824

ITT with 5 bootstrap samples and competing events

options <- SEQopts(km.curves = TRUE,               
                   bootstrap = TRUE,                
                   bootstrap.nboot = 5,
                   # Using LTFU as our competing event
                   compevent = "LTFU")

data <- SEQdata.LTFU
model <- SEQuential(data, id.col = "ID", 
                          time.col = "time", 
                          eligible.col = "eligible", 
                          treatment.col = "tx_init", 
                          outcome.col = "outcome", 
                          time_varying.cols = c("N", "L", "P"), 
                          fixed.cols = "sex",
                          method = "ITT", 
                          options = options)
#> 
#> Full dataset: 54,687 observations, 13 variables
#> 
#> Non-required columns provided, pruning for efficiency
#> 
#> Pruned
#> 
#> Original dataset (eligible subjects): 29,624 observations, 10 variables
#> 
#> Expanding Data...
#> 
#> Pre-filter expansion: 1,609,859 observations
#> 
#> Expanded dataset: 1,119,229 observations, 14 variables
#> 
#> Expansion Successful
#> 
#> Final analysis dataset: 1,119,229 observations, 14 variables
#> 
#> Moving forward with ITT analysis
#> 
#> Bootstrapping with 80% of 1,000 subjects (800 subjects, ~895,383 observations per resample) 5 times
#> 
#> ITT model created successfully
#> 
#> Creating Survival curves
#> 
#> Completed

km_curve(model, plot.type = "risk")

risk_data(model)
#> Index: <Followup>
#>    Method Followup      A       Risk 95% LCI    95% UCI         SE
#>    <char>    <num> <char>      <num>   <num>      <num>      <num>
#> 1:    ITT       60      0 0.02185652       0 0.05286839 0.01582267
#> 2:    ITT       60      1 0.02381601       0 0.04835280 0.01251900
risk_comparison(model)
#>    Followup    A_x    A_y Risk Ratio RR 95% LCI RR 95% UCI Risk Differerence
#>       <num> <fctr> <fctr>      <num>      <num>      <num>             <num>
#> 1:       60  inc_0  inc_1  1.0896524  0.5100804   2.327755       0.001959489
#> 2:       60  inc_1  inc_0  0.9177239  0.4295985   1.960475      -0.001959489
#>      RD 95% LCI  RD 95% UCI
#>           <num>       <num>
#> 1: -0.007920837 0.011839816
#> 2: -0.011839816 0.007920837

ITT hazard ratio with 5 bootstrap samples and competing events

options <- SEQopts(# km.curves must be set to FALSE to turn on hazard 
                   # ratio creation
                   km.curves = FALSE,
                   # set hazard to TRUE for hazard ratio creation
                   hazard = TRUE,
                   bootstrap = TRUE,                
                   bootstrap.nboot = 5,     
                   compevent = "LTFU")

data <- SEQdata.LTFU                          
model <- SEQuential(data, id.col = "ID", 
                          time.col = "time", 
                          eligible.col = "eligible", 
                          treatment.col = "tx_init", 
                          outcome.col = "outcome", 
                          time_varying.cols = c("N", "L", "P"), 
                          fixed.cols = "sex",
                          method = "ITT", 
                          options = options)
#> 
#> Full dataset: 54,687 observations, 13 variables
#> 
#> Non-required columns provided, pruning for efficiency
#> 
#> Pruned
#> 
#> Original dataset (eligible subjects): 29,624 observations, 10 variables
#> 
#> Expanding Data...
#> 
#> Pre-filter expansion: 1,609,859 observations
#> 
#> Expanded dataset: 1,119,229 observations, 14 variables
#> 
#> Expansion Successful
#> 
#> Final analysis dataset: 1,119,229 observations, 14 variables
#> 
#> Moving forward with ITT analysis
#> 
#> Bootstrapping with 80% of 1,000 subjects (800 subjects, ~895,383 observations per resample) 5 times
#> 
#> Completed

# retrieve hazard ratios
hazard_ratio(model)
#> Hazard ratio          LCI          UCI 
#>    1.0033697    0.5993046    1.6798651

ITT with 5 bootstrap samples and competing events in subgroups defined by sex

options <- SEQopts(km.curves = TRUE,               
                   bootstrap = TRUE,                
                   bootstrap.nboot = 5,     
                   compevent = "LTFU",
                   # define the subgroup
                   subgroup = "sex")

data <- SEQdata.LTFU
model <- SEQuential(data, id.col = "ID", 
                          time.col = "time", 
                          eligible.col = "eligible", 
                          treatment.col = "tx_init", 
                          outcome.col = "outcome", 
                          time_varying.cols = c("N", "L", "P"), 
                          fixed.cols = "sex",
                          method = "ITT", 
                          options = options)
#> 
#> Full dataset: 54,687 observations, 13 variables
#> 
#> Non-required columns provided, pruning for efficiency
#> 
#> Pruned
#> 
#> Original dataset (eligible subjects): 29,624 observations, 11 variables
#> 
#> Expanding Data...
#> 
#> Pre-filter expansion: 1,609,859 observations
#> 
#> Expanded dataset: 1,119,229 observations, 14 variables
#> 
#> Expansion Successful
#> 
#> Final analysis dataset: 1,119,229 observations, 14 variables
#> 
#> Moving forward with ITT analysis
#> 
#> Bootstrapping with 80% of 1,000 subjects (800 subjects, ~895,383 observations per resample) 5 times
#> 
#> ITT model created successfully
#> 
#> Creating Survival Curves for sex_0 
#> 
#> Creating Survival Curves for sex_1 
#> 
#> Completed

km_curve(model, plot.type = "risk")
#> $sex_0

#> 
#> $sex_1

risk_data(model)
#> $sex_0
#> Index: <Followup>
#>    Method Followup      A       Risk 95% LCI   95% UCI         SE
#>    <char>    <num> <char>      <num>   <num>     <num>      <num>
#> 1:    ITT       60      0 0.04213833       0 0.1185452 0.03898383
#> 2:    ITT       60      1 0.04911213       0 0.1322803 0.04243352
#> 
#> $sex_1
#> Index: <Followup>
#>    Method Followup      A       Risk     95% LCI    95% UCI          SE
#>    <char>    <num> <char>      <num>       <num>      <num>       <num>
#> 1:    ITT       60      0 0.01577026 0.000000000 0.03706622 0.010865485
#> 2:    ITT       60      1 0.01484521 0.003496357 0.02619406 0.005790336
risk_comparison(model)
#> $sex_0
#>    Followup    A_x    A_y Risk Ratio   RR 95% LCI RR 95% UCI Risk Differerence
#>       <num> <fctr> <fctr>      <num>        <num>      <num>             <num>
#> 1:       60  inc_0  inc_1  1.1654977 2.006387e-08   67703041       0.006973797
#> 2:       60  inc_1  inc_0  0.8580026 1.477039e-08   49840838      -0.006973797
#>     RD 95% LCI RD 95% UCI
#>          <num>      <num>
#> 1: -0.02096462 0.03491222
#> 2: -0.03491222 0.02096462
#> 
#> $sex_1
#>    Followup    A_x    A_y Risk Ratio RR 95% LCI RR 95% UCI Risk Differerence
#>       <num> <fctr> <fctr>      <num>      <num>      <num>             <num>
#> 1:       60  inc_0  inc_1  0.9413422  0.4013910   2.207635     -0.0009250492
#> 2:       60  inc_1  inc_0  1.0623130  0.4529734   2.491336      0.0009250492
#>     RD 95% LCI RD 95% UCI
#>          <num>      <num>
#> 1: -0.01668972 0.01483962
#> 2: -0.01483962 0.01668972