Package 'OTRselect'

Title: Variable Selection for Optimal Treatment Decision
Description: A penalized regression framework that can simultaneously estimate the optimal treatment strategy and identify important variables. Appropriate for either censored or uncensored continuous response.
Authors: Wenbin Lu, Hao Helen Zhang, Donglin Zeng, Yuan Geng, and Shannon T. Holloway
Maintainer: Shannon T. Holloway <[email protected]>
License: GPL-2
Version: 1.2
Built: 2024-12-19 05:07:45 UTC
Source: https://github.com/cran/OTRselect

Help Index


Variable Selection for Optimal Treatment Decision

Description

A penalized regression framework that can simultaneously estimate the optimal treatment strategy and identify important variables. Appropriate for either censored or uncensored continuous response.

Details

The DESCRIPTION file:

Package: OTRselect
Type: Package
Title: Variable Selection for Optimal Treatment Decision
Version: 1.2
Date: 2023-11-24
Author: Wenbin Lu, Hao Helen Zhang, Donglin Zeng, Yuan Geng, and Shannon T. Holloway
Maintainer: Shannon T. Holloway <[email protected]>
Description: A penalized regression framework that can simultaneously estimate the optimal treatment strategy and identify important variables. Appropriate for either censored or uncensored continuous response.
License: GPL-2
Depends: stats, lars, survival, methods
NeedsCompilation: no
Packaged: 2023-11-24 17:24:43 UTC; 19194
Date/Publication: 2023-11-24 17:50:02 UTC
Repository: https://sth1402.r-universe.dev
RemoteUrl: https://github.com/cran/OTRselect
RemoteRef: HEAD
RemoteSha: 18f05e6571e65bae065574d56bd1d3c042733967

Index of help topics:

OTRselect-package       Variable Selection for Optimal Treatment
                        Decision
Qhat                    Mean Response or Restricted Mean Response Given
                        a Treatment Regime
censored                Variable Selection for Optimal Treatment
                        Decision with Censored Survival Times
uncensored              Variable Selection for Optimal Treatment
                        Decision with Uncensored Continuous Response

Function censored performs variable selection for censored continuous response. Function uncensored performs variable selection for uncensored continuous response. Function Qhat estimates the restricted mean response given a treatment regime for censored data or the mean response given a treatment regime for uncensored data.

Author(s)

Wenbin Lu, Hao Helen Zhang, Donglin Zeng, Yuan Geng, and Shannon T. Holloway

Maintainer: Shannon T. Holloway <[email protected]>

References

Lu, W., Zhang, H. H., and Zeng. D. (2013). Variable selection for optimal treatment decision. Statistical Methods in Medical Research, 22, 493–504. PMCID: PMC3303960.

Geng, Y., Lu, W., and Zhang, H. H. (2015). On optimal treatment regimes selection for mean survival time. Statistics in Medicine, 34, 1169–1184. PMCID: PMC4355217.


Variable Selection for Optimal Treatment Decision with Censored Survival Times

Description

A penalized regression framework that can simultaneously estimate the optimal treatment strategy and identify important variables when the response is continuous and censored. This method uses an inverse probability weighted least squares estimation with adaptive LASSO penalty for variable selection.

Usage

censored(x, y, a, delta, propen, phi, logY = TRUE, 
         intercept = TRUE)

Arguments

x

Matrix or data.frame of model covariates.

y

Vector of response. Note that this data is used to estimate the Kaplan-Meier Curve and should not be log(T).

a

Vector of treatment received. Treatments must be coded as integers or numerics that can be recast as integers without loss of information.

delta

Event indicator vector. The indicator must be coded as 0/1 where 0=no event and 1=event.

propen

Vector or matrix of propensity scores for each treatment. If a vector, the propensity is assumed to be the same for all samples. Column or element order must correspond to the sort order of the treatment variable, i.e., 0,1,2,3,... If the number of columns/elements in propen is one fewer than the total number of treatment options, it is assumed that the base or lowest valued treatment has not been provided.

phi

A character {'c' or 'l'} indicating if the constant ('c') or linear ('l') baseline mean function is to be used.

logY

TRUE/FALSE indicating if log(y) is to be used for regression.

intercept

TRUE/FALSE indicating if an intercept is to be included in phi model.

Value

A list object containing

beta

A vector of the estimated regression coefficients after variable selection.

optTx

The estimated optimal treatment for each sample.

Author(s)

Wenbin Lu, Hao Helen Zhang, Yuan Geng, and Shannon T. Holloway

References

Geng, Y., Lu, W., and Zhang, H. H. (2015). On optimal treatment regimes selection for mean survival time. Statistics in Medicine, 34, 1169–1184. PMCID: PMC4355217.

Examples

sigma <- diag(10)
  ct <- 0.5^{1L:9L}
  rst <- unlist(sapply(1L:9L,function(x){ct[1L:{10L-x}]}))
  sigma[lower.tri(sigma)] <- rst
  sigma[upper.tri(sigma)] <- t(sigma)[upper.tri(sigma)]

  M <- t(chol(sigma))
  Z <- matrix(rnorm(1000),10,100)
  X <- t(M%*%Z)

  A <- rbinom(100,1,0.5)

  Y <- rweibull(100,shape=0.5,scale=1)
  C <- rweibull(100,shape=0.5,scale=1.5)

  delta <- as.integer(C <= Y)

  Y[delta > 0.5] <- C[delta>0.5]

  dat <- data.frame(X,A,exp(Y),delta)
  colnames(dat) <- c(paste("X",1:10,sep=""),"a","y","del")
  
  censored(x = X, 
           y = Y, 
           a = A, 
           delta = delta,
           propen = 0.5, 
           phi = "c", 
           logY = TRUE, 
           intercept = TRUE)

Mean Response or Restricted Mean Response Given a Treatment Regime

Description

Estimates the mean response given a treatment regime if data is uncensored. If data is censored, estimates the restricted mean response given a treatment regime.

Usage

Qhat(y, a, g, wgt = NULL)

Arguments

y

vector of responses. Note if logY = TRUE in censored, this value should also be the logarithm.

a

vector of treatments received.

g

vector of the given treatment regime.

wgt

weights to be used if response is censored.

Value

Returns the estimated mean response or restricted mean response.

Author(s)

Wenbin Lu, Hao Helen Zhang, Donglin Zeng, Yuan Geng, and Shannon T. Holloway

References

Lu, W., Zhang, H. H., and Zeng. D. (2013). Variable selection for optimal treatment decision. Statistical Methods in Medical Research, 22, 493–504. PMCID: PMC3303960.

Geng, Y., Lu, W., and Zhang, H. H. (2015). On optimal treatment regimes selection for mean survival time. Statistics in Medicine, 34, 1169–1184. PMCID: PMC4355217.

Examples

y <- rnorm(100)
  a <- rbinom(100,1,0.5)
  g <- integer(100)

  Qhat(y = y, a = a, g = g)

Variable Selection for Optimal Treatment Decision with Uncensored Continuous Response

Description

A penalized regression framework that can simultaneously estimate the optimal treatment strategy and identify important variables when the response is continuous and not censored. This method uses an inverse probability weighted least squares estimation with adaptive LASSO penalty for variable selection.

Usage

uncensored(x, y, a, propen, phi, intercept = TRUE)

Arguments

x

Matrix or data.frame of model covariates.

y

Vector of response. Note that this data is used to estimate the Kaplan-Meier Curve and should not be log(T).

a

Vector of treatment received. Treatments must be coded as integers or numerics that can be recast as integers without loss of information.

propen

Vector or matrix of propensity scores for each treatment. If a vector, the propensity is assumed to be the same for all samples. Column or element order must correspond to the sort order of the treatment variable, i.e., 0,1,2,3,... If the number of columns/elements in propen is one fewer than the total number of treatment options, it is assumed that the base or lowest valued treatment has not been provided.

phi

A character {'c' or 'l'} indicating if the constant ('c') or linear ('l') baseline mean function is to be used.

intercept

TRUE/FALSE indicating if an intercept is to be included in phi model.

Value

A list object containing

beta

A vector of the estimated regression coefficients after variable selection.

optTx

The estimated optimal treatment for each sample.

Author(s)

Wenbin Lu, Hao Helen Zhang, Donglin Zeng, and Shannon T. Holloway

References

Lu, W., Zhang, H. H., and Zeng. D. (2013). Variable selection for optimal treatment decision. Statistical Methods in Medical Research, 22, 493–504. PMCID: PMC3303960.

Examples

sigma <- diag(10)
  ct <- 0.5^{1L:9L}
  rst <- unlist(sapply(1L:9L,function(x){ct[1L:{10L-x}]}))
  sigma[lower.tri(sigma)] <- rst
  sigma[upper.tri(sigma)] <- t(sigma)[upper.tri(sigma)]

  M <- t(chol(sigma))
  Z <- matrix(rnorm(1000),10,100)
  X <- t(M %*% Z)

  gamma1 <- c(1, -1, rep(0,8))
  beta <- c(1,1,rep(0,7), -0.9, 0.8)

  A <- rbinom(100,1,0.5)

  Y <- 1.0 + X %*% gamma1 + 
       A*{cbind(1.0,X)%*%beta} + rnorm(100,0,.25)

  dat <- data.frame(X,A,Y)
  
  uncensored(x=X,  
             y = Y,  
             a = A,  
             propen = 0.5,  
             phi = "c",  
             intercept = TRUE)