Condition tag co-occurrence

Heatmap of pairwise condition-tag overlap among the top 15 most-used tags. The diagonal is the count of papers carrying the tag (i.e. self-co-occurrence); off-diagonal cells show how many papers are tagged with both. Color is on a log10 scale so the diagonal doesn't visually swamp the rest.

A high co-occurrence between two tags doesn't mean the papers literally discuss both conditions in equal depth; it means the abstract or MeSH list mentioned both. The condition tagger uses a curated MeSH + SNOMED-CT vocabulary in ``condition_tags_vocab``.