title: The International Primary Pulmonary Hypertension Study (IPPHS).
mesh_terms: D015982:Bias; D016022:Case-Control Studies; D015986:Confounding Factors, Epidemiologic; D004992:Ethics, Medical; D005060:Europe / Q000453:epidemiology; D006801:Humans; D006976:Hypertension, Pulmonary / Q000175:diagnosis / Q000453:epidemiology* / Q000209:etiology; D015994:Incidence; D015337:Multicenter Studies as Topic; D010361:Patients; D015995:Prevalence; D012042:Registries; D012107:Research Design