Unstructured discharge notes in Electronic Health Records (EHRs) often carry signal complementary to structured medical codes, holding patient-specific evidence that standardized cohort-level codes alone cannot capture. However, this evidence in notes is frequently buried in lengthy, noisy text that is not intentionally written with any specific clinical prediction in mind. Summarization is an obvious mitigation, but generic summaries, tuned for fluency rather than the outcome, routinely omit decisive evidence while retaining plausible but uninformative detail. To this end, we propose RASPER, a Reward-Aligned Summarizer for Prediction in EHR, that optimizes note summarization directly against the downstream clinical task. RASPER employs a tunable LLM-based summarizer to extract task-relevant evidence from discharge notes and trains it via reinforcement learning from prediction feedback, using a reward derived from the downstream predictor's loss. To ground the summarizer, a longitudinal encoder converts structured codes into soft prompts that incorporate each patient's clinical context into note summarization. By rewarding the quality of the resulting multimodal prediction, RASPER encourages the summarizer to retain patient-specific evidence that complements, rather than duplicates, information captured by structured codes. RASPER consistently outperforms strong baselines on both readmission prediction and medication recommendation across MIMIC-III and MIMIC-IV.
Figures & tables
Figure 1: Overview of the proposed RASPER framework. A tunable LLM summarizer transforms discharge notes into standardized visit-level summaries, which are concatenated into a patient-level summary. An LLM-aware predictor combines this patient-level summary with soft prompt embeddings from structured EHR codes for outcome prediction. The summarizer is first initialized with supervised fine-tuning and then optimized with RLPF using prediction-loss-derived reward within the PPO objective.
Figure 2: Prompt used by the tunable LLM summarizer to extract relevant information from discharge notes.
Component
Hyperparameter / Symbol
Value
Soft prompt encoder
P
8
LLM hidden size
D
2304
Max Summary length
Ci
512
Reward normalization
ϵ
1×10−8
Reward clipping
rmax
2.0
PPO clipping
ϵPPO
0.2
Table 2: Hyperparameters used in the proposed framework.
MIMIC-III
MIMIC-IV
Model
Readmission
Medication
Readmission
Medication
AUROC
PRAUC
F1
Jaccard
AUROC
PRAUC
F1
Jaccard
DL-based Methods
Deepr Nguyen et al. (2017)
0.671
0.702
0.255
0.160
0.621
0.651
0.228
0.189
RETAIN Choi et al. (2016)
0.657
0.678
0.253
0.156
0.673
0.698
0.349
0.255
GRASP Zhang et al. (2021)
0.618
0.635
0.153
0.096
0.535
0.578
0.267
0.195
Table 3: Baseline performance comparison on MIMIC-III and MIMIC-IV. Best results are in bold, and underlined results denote the second-best results that are statistically lower at the 95% confidence level.
MIMIC-III
MIMIC-IV
Model Variant
Readmission
Medication
Readmission
Medication
AUROC
PRAUC
F1
Jaccard
AUROC
PRAUC
F1
Jaccard
RASPER w/o EHR encoder
0.661
0.698
0.288
0.187
0.685
0.704
0.353
0.258
RASPER w/o Summarization
0.674
0.712
0.298
0.191
0.691
0.713
0.363
0.262
RASPER w/o RL (GPT only)
0.689
0.725
0.309
0.201
0.708
0.723
0.371
0.272
RASPER w/o RL (SFT only)
0.684
0.721
0.305
0.198
0.701
0.718
0.367
0.269
Table 4: Ablation studies on MIMIC-III and MIMIC-IV. Best results are in bold, and underlined results denote the second-best results that are statistically lower at the 95% confidence level.
Figure 3: Performance comparison across different EHR models on MIMIC-III and MIMIC-IV.
MIMIC-III
MIMIC-IV
Backbone
Readmission
Medication
Readmission
Medication
AUROC
PRAUC
F1
Jaccard
AUROC
PRAUC
F1
Jaccard
Llama-3.2-1B
0.701
0.734
0.321
0.214
0.722
0.737
0.384
0.278
Qwen2.5-0.5B
0.697
0.730
0.315
0.209
0.716
0.731
0.379
0.276
Gemma-2-2B
0.704
0.738
0.326
0.218
0.725
0.742
0.388
0.282
Table 5: Comparison of LLM backbones on MIMIC-III and MIMIC-IV across two tasks.
Appendix figures & tables1 asset
Supplementary material from the paper’s appendix.
Appendix
Model
Time (s)
Deepr
0.09
RETAIN
0.06
GRASP
0.17
AdaCare
0.05
StageNet
0.11
Adore
0.21
Appendix
Table 6: Inference time comparison for a batch of 12 patients.
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