Figure 5. Mutual information between the primary and secondary diagnoses of the ICU patients.

Shown are the mutual information values calculated from 296 × 252 3-digit ICD9 codes (level-3 categories) as well as 17 × 16 level-1 and 89 × 76 level-2 categories, by the proposed method with p-value threshold 0.5 (red) and the conventional method (black).