Objectives: Analyze the decision to enact or to refrain from chemoprophylaxis (CP) with isoniazide (INH) in patients who are intravenous drug users (IVDU) in Spain infected by the human immunodeficiency virus (HIV), either classified or not with hypersensitive skin tests.
Methods: With the bibliographic information available and the help of decision tree, an analysis of the effectiveness and of the consequences of drug costs of CP with INH in those patients is performed.
Results: Overall, the HIV+ IVDU benefit from CP is an increase in survival of 80 days, with a savings of 7,252 pesetas per patient. The intradermal reaction with PPD and the retarded hypersensitivity tests (HCR) allow us to classify them in three subgroups: a) PPD+ where CP is universally admitted and thus corroborates our study; b) PPD-/HCR- where CP increases survival 201 days and saves 20,616 pesetas per patient; and c) PPD-/HCR+ where survival is increased 33 days and the pharmacological costs increase 1,536 pesetas per patient under CP.
Conclusions: For the present situation in Spain, CP with INH is effective in HIV+ IVDU patients, independent of the results of the intradermal reaction skin tests.