With increasing age, blood pressure (BP) rises as a consequence of arterial stiffness. It has been debated whether it is beneficial to treat hypertension in old age especially in >75-year... Show moreWith increasing age, blood pressure (BP) rises as a consequence of arterial stiffness. It has been debated whether it is beneficial to treat hypertension in old age especially in >75-year-olds when they have multimorbidity, polypharmacy or frailty. Large trials showed that lowering BP in >60-year-olds is beneficial and lowers the risk for myocardial infarction, stroke and all-cause mortality. However, these trials lack generalizability and typically excluded multimorbid patients that are frail. At the same time, observational studies rose concerns about lowering BP too much since there are several cohort studies showing a reverse association of low BP and increased mortality especially in >75-year-olds. The general aim of this thesis is to increase the scientific knowledge about the effects of treating hypertension in >75-year-olds with frailty. This thesis has three aims: 1) to measure the prevalence of polypharmacy in older patients; 2) to test for an association between low SBP and mortality, cognitive function, daily functioning, and QoL in older patients under antihypertensive treatment; and 3) to understand the role that frailty plays in GP decisions about treating hypertension in old age across countries and see if those differences can be explained by country-specific cardiovascular disease burden and life expectancy. Show less