Definition of variables

OOP payments included all health-related costs that were paid for any medical service17 and those for any type of drug used in the in-patient or out-patient setting as well as the emergency department. Payments for extra services or reimbursements were excluded in estimating OOP payments.8

A household's capacity to pay was the household's total income minus subsistence costs and food costs.8,17 Although food expenditure excluded cost of food eaten outside the home, there was no proper information about spending in restaurants in the KHPS. Thus, the total cost of food consumption was taken as food expenditure in this study.

CHE was defined by the World Health Organization (WHO) when direct health care costs exceeded 40% of a household's capacity to pay, and the threshold was adjusted for each country.18 The frequency of CHEs can vary depending on the level of threshold used,19 and there is controversy over the ideal threshold. Most researchers apply thresholds between 10% and 40%17,20,21,22,23,24,25; we evaluated CHEs at 10%, 20%, 30%, and 40% thresholds.