[The indirect costs of tension type headache. A systematic literature review].

Objective: The objective of this work was to systematically review the published literature in relation to the estimated indirect costs associated with TTH.

Design: This systematic review followed the Preferred Reporting Items Statement for Systematic Reviews and Meta-analyzes (PRISMA).

Data Sources: The review was performed in two main databases, PubMed and EconLit, and was completed with the gray literature search.