Table 1.

Coding for data elements of the PatientsLikeMe terminology.

Medical entity type	Examples	Terminology
Condition	Multiple sclerosis, epilepsy, traumatic brain injury, major depressive disorder	Systematized Nomenclature of Medicine-Clinical Terms (SNOMED CT), International Classification of Diseases-10 (ICD10), Medical Dictionary for Regulatory Activities (MedDRA)
Symptom	Depressed mood, anxious mood, fatigue, insomnia, pain	SNOMED CT, ICD10, MedDRA, International Classification of Functioning, Disability and Health
Treatment	Gabapentin, vitamin D, physical therapy, cognitive behavioral therapy	RxTerms
Side effect	May be coded to a condition or symptom	See above for Terminology
Treatment purpose	May be coded to a condition or symptom	See above for Terminology
Hospitalization reason	May be coded to a condition, symptom, or treatment	See above for Terminology