Table 1. ICD-9 codes used to retrieve the sets of patients of the three rare diseases and the two control groups from NYPH EHR (2004–2009).

Rare disease	ICD-9 codes	Number of patients
Kaposi sarcoma	176, 176.0, 176.1, 176.2, 176.3, 176.4, 176.5, 176.8, 176.9	221
Toxoplasmosis	130, 130.0, 130.1, 130.2, 130.3, 130.4, 130.5, 130.7, 130.8, 130.9	138
Kawasaki disease	446.1	213
Post-traumatic stress disorder (control)	309.81	1281
Influenza (control)	487, 487.0, 487.1, 487.8	2582