Impact of drug burden index on adverse health outcomes in Irish community-dwelling older people: a cohort study

BMC Geriatrics

Table 1 Description of covariates adjusted for in multivariate regression models

Variable	Format	Description of categories
Age (in years)	Continuous	N/A
Sex	Binary	Male (reference)
Sex	Binary	Female
Education level	Categorical	None or Primary (reference)
		Secondary
		Tertiary
Living arrangements	Binary	Living alone (reference)
Living arrangements	Binary	Living with spouse or others
Polypharmacy^a	Binary	No (reference)
Polypharmacy^a	Binary	Yes
Number of chronic diseases^b	Categorical	0 (reference)
		1
		2
		3 or more
Depression^c	Categorical	None/mild (reference)
		Moderate
		Severe
Cognitive function^d	Binary	Normal (MMSE≥25, reference)
Cognitive function^d	Binary	Impaired (MMSE< 25)
Disability^e	Binary	No (reference)
Disability^e	Binary	Yes (any ADL or IADL difficulty)

^aPolypharmacy defined as taking > 5 regular medications
^bThe number of doctor-diagnosed chronic conditions reported by participants from the following list: cardiovascular disease (heart attack, heart failure or angina), cataracts, hypertension, high cholesterol, stroke, diabetes, lung disease, asthma, arthritis, osteoporosis, cancer, Parkinson’s disease, peptic ulcer, and hip fracture
^cLevel of depressive symptoms was determined using the Centre for Epidemiological Studies Depression scale [14], based on the participant’s self-completion questionnaire
^dCognitive function was determined using the Mini-Mental State Examination (MMSE) [15], based on the participant’s self-completion questionnaire
^eDisability was defined as at least one self-reported difficulty with any task listed in either the Activities of Daily Living (ADL) scale [10], or the Instrumental Activities of Daily Living (IADL) scale [11]

ISSN: 1471-2318