怎样绘制结局为四分类的临床决策曲线?请告诉R代码。
时间: 2023-06-07 16:07:30 浏览: 56
以下是R代码:
# Step 1: Load necessary packages
library(survival)
library(rms)
# Step 2: Load dataset
data(lung)
# Step 3: Prepare data for analysis
lung$status <- ifelse(lung$status == 1, "dead", "alive")
lung$status <- factor(lung$status, levels = c("alive", "dead"))
lung$sex <- factor(lung$sex, levels = c("male", "female"))
lung$ph.ecog <- factor(lung$ph.ecog, levels = c(0, 1, 2, 3, 4))
# Step 4: Create Cox proportional hazards model
coxph_model <- coxph(Surv(time, status) ~ age + sex + ph.ecog + wt.loss, data = lung)
# Step 5: Create predicted probabilities for each observation in the dataset
lung$predicted_probabilities <- predict(coxph_model, type = "lp")
lung$predicted_probabilities <- (exp(lung$predicted_probabilities)) / (1 + exp(lung$predicted_probabilities))
# Step 6: Create quartiles based on predicted probabilities
lung$quartiles <- ntile(lung$predicted_probabilities, 4)
# Step 7: Plot the results
plotROC(lung$status, lung$predicted_probabilities, plot = "curves", col = lung$quartiles)