“…Among the 14 indirect cost studies, eight were observational [34][35][36]39,41,43,44,47] and six were model-based, including economic evaluations or retrospective cost-of-illness studies based on published estimates reporting indirect cost inputs for their economic models [37,38,40,42,45,46]. Among the observational studies, two each were conducted in Denmark and Ireland and one each in the UK, Russia, Mexico and India.…”