grouping

A Node.js wrapper for the official ATIH grouping engine used in the French PMSI (Programme de Médicalisation des Systèmes d'Information).

This package allows integration of the native C-based groupage module to classify hospital stays into GHM (Groupe Homogène de Malades) and GHS (Groupe Homogène de Séjours) codes, in compliance with the T2A billing system in France.

Overview

This project implements a Node.js native addon using Node-API to wrap the official ATIH (Agence Technique de l'Information sur l'Hospitalisation) grouping engine. The grouping engine is a critical component of the French healthcare system's billing and classification infrastructure.

French Medical Coding Context

The French healthcare system uses the PMSI (Programme de Médicalisation des Systèmes d'Information) for medical activity coding and hospital billing under the T2A (Tarification À l'Activité) system. This project specifically addresses the need for automated grouping of medical stays into standardized categories.

For comprehensive background on grouping algorithms and medical coding in France, refer to this detailed overview.

Technical Architecture

This package consists of:

Native C/C++ Module: The core ATIH grouping engine in the src folder
JavaScript Interface: High-level Node.js API for application integration
Type Definitions: TypeScript definitions for development support

Installation

pnpm add @beparallel/grouping

Requirements

Node.js 22.0.0 or higher
Compatible with Windows, macOS, and Linux
Native compilation tools (node-gyp)

📚 Additional Resources

Format of the RSS non grouped data: doc/022_format.md
Format of the RSS grouped data: doc/122_format.md
Grouping algorithm: doc/grouping_method.md

API Reference

Basic Usage

import { grp } from '@beparallel/grouping'

const result = grp.grp2025({...})

Input Format

The module expects RSS (Résumé de Sortie Standardisé) formatted data conforming to ATIH specifications:

const rssData = {
  // Patient demographics
  age: 65,
  sex: 'M',

  // Medical coding
  mainDiagnosis: 'I21.0',
  secondaryDiagnoses: ['E11.9', 'N18.6'],
  procedures: ['DEQP003'],

  // Stay information
  entryMode: '6',
  exitMode: '9',
  lengthOfStay: 7,

  // Additional classification data
  severity: 2,
  complexity: 1
}

Output Format

{
  ghm: 'GHM_CODE',        // Groupe Homogène de Malades
  ghs: 'GHS_CODE',        // Groupe Homogène de Séjours
  severity: 2,            // Severity level
  complexity: 1,          // Complexity level
  errors: [],             // Array of error codes/messages
  warnings: [],           // Array of warning messages
  processingTime: 1.2     // Processing time in milliseconds
}