Table 1.

Operational definition of specific HIV indicator conditions

Condition in national guidelines10	Operational definition used in the THIN model
Space-occupying lesion of unknown cause	Space-occupying lesion
Peripheral neuropathy	Excluded Read codes attributing condition to diabetes
Dementia	Dementia diagnosed under the age of 65 years
Severe or recalcitrant seborrhoeic dermatitis	Number of consultations for seborrhoeic dermatitis in specified period
Severe or recalcitrant psoriasis	Number of consultations for psoriasis dermatitis in specified period
Multidermatomal or recurrent herpes zoster	Herpes zoster
Chronic diarrhoea of unknown cause	Number of consultations for diarrhoea in specified period
Weight loss of unknown cause	Weight loss
Any unexplained blood dyscrasia	Blood dyscrasia
Any unexplained retinopathy	Retinopathy in a non-diabetic patient
Lymphadenopathy of unknown cause	Lymphadenopathy
Chronic parotitis	Parotitis