Model

Overview

This page presents the statistical model predicting immunotherapy use in patients with lung adenocarcinoma. Since the question is Predictive, we will use a logistic regression to model the data.

Table

# A tibble: 9 × 7
  term                   estimate std.error statistic p.value conf.low conf.high
  <chr>                     <dbl>     <dbl>     <dbl>   <dbl>    <dbl>     <dbl>
1 (Intercept)             -0.794    0.534      -1.49  0.137   -1.86      0.239  
2 `Age at Surgery/Biops…  -0.0169   0.00741    -2.28  0.0228  -0.0314   -0.00230
3 SexMale                 -0.0523   0.167      -0.312 0.755   -0.384     0.274  
4 `Race Category`Black     0.460    0.448       1.03  0.305   -0.439     1.33   
5 `Race Category`Other     0.476    0.629       0.757 0.449   -0.825     1.68   
6 `Race Category`Unknown   0.667    0.436       1.53  0.126   -0.199     1.52   
7 `Race Category`White     0.251    0.284       0.886 0.376   -0.284     0.834  
8 `TP53 Pathway`Yes        0.452    0.177       2.56  0.0106   0.110     0.804  
9 `TMB (nonsynonymous)`    0.0222   0.00833     2.66  0.00777  0.00599   0.0388 

According to this table, we can interpret that if you have a TP53 pathway, you are 45.2% more likely to recieve immmunotherapy after a surgery/biopsy. This estimate is statistically significant which is proven by the low p value of 0.0106 and the confidence interval (0.110 to 0.804) not including the number 0.

Data Generating Mechanism

The probability \(p_i\) of a patient receiving post-sample immunotherapy is modeled using logistic regression:

\[\text{logit}(p_i) = \ln\left(\frac{p_i}{1 - p_i}\right) = \beta_0 + \beta_1(\text{Age}_i) + \beta_2(\text{Sex}_{\text{Male}, i}) + \beta_3(\text{Race}_{\text{Black}, i}) + \beta_4(\text{Race}_{\text{Other}, i}) + \beta_5(\text{Race}_{\text{Unknown}, i}) + \beta_6(\text{Race}_{\text{White}, i}) + \beta_7(\text{TP53}_{\text{Yes}, i}) + \beta_8(\text{TMB}_i)\]

Using the estimated parameters from our model:

\[\text{logit}(p_i) = -0.794 - 0.0169(\text{Age}_i) - 0.0523(\text{Sex}_{\text{Male}, i}) + 0.460(\text{Race}_{\text{Black}, i}) + 0.476(\text{Race}_{\text{Other}, i}) + 0.667(\text{Race}_{\text{Unknown}, i}) + 0.251(\text{Race}_{\text{White}, i}) + 0.452(\text{TP53}_{\text{Yes}, i}) + 0.0222(\text{TMB}_i)\]