/ODTRE_IE

Optimal dynamic treatment regime estimation (ODTRE) using information extraction (IE) from unstructured text

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ODTRE_IE

Optimal dynamic treatment regime estimation (ODTRE) using information extraction (IE) from unstructured text

Table of contents

Overview

This project extracts information from clinical text to generate patient level information in structured electronic health records (EHRs) format. The proposed optimal dynamic treatment regime (DTR) estimation method is applicable for patient characterization, clinical text analysis, named entity recognition, boundary detection, and negation annotation. The derived patient characteristics are used for Tree-based Reinforcement Learning (T-RL) and estimation of multi-stage optimal DTRs. The ODTRE-IE technique is validated using simulated and clinical blood pressure EHR data.

R Code

The examples, demonstrations and simulations are designed, built, implemented and validated in the R environment.

The source R code for the package is in the package (ODTRE_IE) folder.

Technical Details

Matrix products operations use LAPACK: /Library/Frameworks/R.framework/Versions/4.0/Resources/lib/libRlapack.dylib

attached base packages: stats graphics grDevices utils datasets methods base

other attached packages: [1] latex2exp_0.4.0 nnet_7.3-14 rpart_4.1-15 missForest_1.4
[5] itertools_0.1-3 iterators_1.0.13 foreach_1.5.1 randomForest_4.6-14 [9] ggplot2_3.3.0 dplyr_1.0.6

Part of the data preprocessing code was written in Python (Jupiter Notebook) with the following software versions:

Python version: Python 3.8.6 (v3.8.6:db455296be, Sep 23 2020, 13:31:39) [Clang 6.0 (clang-600.0.57)] Platform: macOS-10.16-x86_64-i386-64bit Imported python libraries: numpy 1.21.1 pandas 1.3.1 re 2.2.1

To access the full dataset (MIMIC III) used in the simulation and application sections in this paper, please complete the following steps: 1. Complete CITI training course 2. Create a PhysioNet account 3. Submit a request to access MIMIC III data 4. Accessing the archive (via download or using a Cloud service such as Google BigQuery or Amazon Web Services)

More information about MIMIC III access is available on this website. More information about the data is available online.

./main_program

(1) master.R This code reproduces the two-stage and three-stage simulation studies and optimal DTR estimation in the application section in the paper. The code also generates Table 1, Figure 1, and Figure 2. It can be executed by command: R CMD BATCH --no-save master.R master_log.txt, after changing the working directory to ./main_program. Results will be saved in the same folder.

The simulation code section loads intermediate results of objects aa, bb, cc, and dd for faster computation. However, readers can also run the original code for themselves, which is commented out in master.R after load().

The application code section loads preprocessed data application_data_day1.csv and application_data_day2.csv, which can be generated using SQL_queries_hyper_emergency_application.txt (on GCP), hyper_ie.ipynb (IE), and hyper_emergency_data_preprocessing.R.

./data

This subfolder contains final text related simulation/application data and the Python and SQL codes to generate these datasets.

./data/data_simulation

(1) SQL queries.txt SQL queries used in Google Cloud Platform (GCP) to extract data from MIMIC III. To request access, please contact PhysioNet for review.

(2) Simulation_text_info_extraction.ipynb Python notebook for simulating clinical text with smoking status and perform information extraction using simulated data. The input data for this notebook is downloaded from GCP as CSV files. The output is the final sim_data.csv for simulation.

(3) sim_data.csv Simulation data that contains simulated and structuralized weight and smoking information from text. Obtained from Simulation_text_info_extraction.ipynb.

(4) two_stage_sim.Rdata Intermediate results for two stage simulation (1000 replicates). Loaded by master.R for saved objects aa and bb.

(5) three_stage_sim.Rdata Intermediate results for three stage simulation (1000 replicates). Loaded by master.R for saved objects cc and dd.

./data/data_hyper_emergency

(1) SQL_queries_hyper_emergency_application.txt SQL queries used in Google Cloud Platform (GCP) to extract data from MIMIC III. To request access, please contact PhysioNet for review. The queries will generate 8 CSV files for data preprocessing.

(2) hyper_ie.ipynb Python notebook for clinical text information extraction. The notebook extracts patients smoking status, weight, and height information from notes.csv (generated from SQL code). The notebook outputs hyper_text_ie.csv to the same folder as structured patient information for data preprocessing.

(3) hyper_emergency_data_preprocessing.R This R code preprocesses the CSV files generated by the SQL code and Python notebook. It outputs preprocessed data application_data_day1.csv and application_data_day2.csv for optimal DTR estimation in the application section. The code can be run using: R CMD BATCH --no-save hyper_emergency_data_preprocessing.R, after changing working directory to ./data/data_hyper_emergency.

(4) application_data_day1.csv (please delete after review) Day one preprocessed application data generated from hyper_emergency_data_preprocessing.R.

(5) application_data_day2.csv (please delete after review) Day two preprocessed application data generated from hyper_emergency_data_preprocessing.R.

./function

(1) Functions.R Contains functions written in R that estimates optimal DTR using Tree-based Reinforcement Learning (T-RL) and simulation functions. All functions are applied in ./main_program/master.R.

(2) plot_tree.R Contains a function for plotting optimal DTR from DTRtree objects. This function is applied in ./main_program/hyper_emergency_dtr_estimation.R.

Team

Nina Zhou, Robert D. Brook, Ivo D. Dinov, Lu Wang, and SOCR Team.

References