Table 3.

Three categories of dependent variables: (1) health and health-related quality of life, (2) other dimensions of quality of life, and (3) economic value of informal care.

Category and dependent variables		Description
Variables related to health and health-related quality of life
	Health-related quality of life	EuroQol: EQ-5D-DL is a self-assessed questionnaire comprised of a 5-component scale including mobility, self-care, usual activities, pain/discomfort, and anxiety/depression [35]
	Perceived health	Likert: bad, fair, good, very good, and excellent
	Deterioration of health because of care	Yes/no
	Experiences a chronic disease	Yes/no, number and type of chronic diseases experienced
	Mental health	GHQ-12a scale [38]
	Lifestyles	Presenting unhealthy behaviors in at least one of the following factors: alcohol consumption, smoking, hours of sleep, physical activity, and diet
	Burden	Zarit Caregiver Burden Scale validated for use in the Spanish population, consists of 22 questions and 5 possible answers scored from 1 to 5, which establishes 12 different degrees of overload depending on the score obtained: without overload, light overload, and intense overload [37]
	Use of health care services	Yes/no, number and type of health care service used
	Medication use	Yes/no, number and type of medications, prescribed or not
Variables related to other dimensions of quality of life
	Problems derived from care, in work, economic, leisure, and family life	Yes/no
	Time to care for self, derived from care	Yes/no
Variable related to economic value of informal care		Value according to the willingness to pay for care and value according to the willingness to be compensated for care

^aGHQ-12: 12-item general health questionnaire.