Multimodal Medical Code Tokenizer

Fuente: arXiv
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Hauptverfasser: Su, Xiaorui, Messica, Shvat, Huang, Yepeng, Johnson, Ruth, Fesser, Lukas, Gao, Shanghua, Sahneh, Faryad, Zitnik, Marinka
Format: Preprint
Veröffentlicht: 2025
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author Su, Xiaorui
Messica, Shvat
Huang, Yepeng
Johnson, Ruth
Fesser, Lukas
Gao, Shanghua
Sahneh, Faryad
Zitnik, Marinka
author_facet Su, Xiaorui
Messica, Shvat
Huang, Yepeng
Johnson, Ruth
Fesser, Lukas
Gao, Shanghua
Sahneh, Faryad
Zitnik, Marinka
contents Foundation models trained on patient electronic health records (EHRs) require tokenizing medical data into sequences of discrete vocabulary items. Existing tokenizers treat medical codes from EHRs as isolated textual tokens. However, each medical code is defined by its textual description, its position in ontological hierarchies, and its relationships to other codes, such as disease co-occurrences and drug-treatment associations. Medical vocabularies contain more than 600,000 codes with critical information for clinical reasoning. We introduce MedTok, a multimodal medical code tokenizer that uses the text descriptions and relational context of codes. MedTok processes text using a language model encoder and encodes the relational structure with a graph encoder. It then quantizes both modalities into a unified token space, preserving modality-specific and cross-modality information. We integrate MedTok into five EHR models and evaluate it on operational and clinical tasks across in-patient and out-patient datasets, including outcome prediction, diagnosis classification, drug recommendation, and risk stratification. Swapping standard EHR tokenizers with MedTok improves AUPRC across all EHR models, by 4.10% on MIMIC-III, 4.78% on MIMIC-IV, and 11.32% on EHRShot, with the largest gains in drug recommendation. Beyond EHR modeling, we demonstrate using MedTok tokenizer with medical QA systems. Our results demonstrate the potential of MedTok as a unified tokenizer for medical codes, improving tokenization for medical foundation models.
format Preprint
id arxiv_https___arxiv_org_abs_2502_04397
institution arXiv
publishDate 2025
record_format arxiv
spellingShingle Multimodal Medical Code Tokenizer
Su, Xiaorui
Messica, Shvat
Huang, Yepeng
Johnson, Ruth
Fesser, Lukas
Gao, Shanghua
Sahneh, Faryad
Zitnik, Marinka
Computation and Language
Artificial Intelligence
Machine Learning
Foundation models trained on patient electronic health records (EHRs) require tokenizing medical data into sequences of discrete vocabulary items. Existing tokenizers treat medical codes from EHRs as isolated textual tokens. However, each medical code is defined by its textual description, its position in ontological hierarchies, and its relationships to other codes, such as disease co-occurrences and drug-treatment associations. Medical vocabularies contain more than 600,000 codes with critical information for clinical reasoning. We introduce MedTok, a multimodal medical code tokenizer that uses the text descriptions and relational context of codes. MedTok processes text using a language model encoder and encodes the relational structure with a graph encoder. It then quantizes both modalities into a unified token space, preserving modality-specific and cross-modality information. We integrate MedTok into five EHR models and evaluate it on operational and clinical tasks across in-patient and out-patient datasets, including outcome prediction, diagnosis classification, drug recommendation, and risk stratification. Swapping standard EHR tokenizers with MedTok improves AUPRC across all EHR models, by 4.10% on MIMIC-III, 4.78% on MIMIC-IV, and 11.32% on EHRShot, with the largest gains in drug recommendation. Beyond EHR modeling, we demonstrate using MedTok tokenizer with medical QA systems. Our results demonstrate the potential of MedTok as a unified tokenizer for medical codes, improving tokenization for medical foundation models.
title Multimodal Medical Code Tokenizer
topic Computation and Language
Artificial Intelligence
Machine Learning
url https://arxiv.org/abs/2502.04397