UBC Theses and Dissertations

UBC Theses Logo

UBC Theses and Dissertations

A new approach to addressing polypharmacy in older Canadians : hypertension treatment intensity McCracken, Rita Katherine


This dissertation develops the concept of treatment intensity of asymptomatic conditions (such as hypertension) by examining the potential link between drug treatment for asymptomatic conditions and polypharmacy. Research addressing overtreatment has typically focused on reducing either the total number of medications or identification of potentially inappropriate medications. Multi-morbidity, including both symptomatic, e.g. arthritis, and asymptomatic conditions, e.g. hypertension, increases with age and may be an important driver of increased polypharmacy. Hypothesis #1: There is an association between treatment intensity of hypertension and general polypharmacy. Treatment of hypertension has shown that it can reduce the risk of morbidity and mortality in studied populations. However, the evidence for benefit of treatment in people ≥70 years old has not been consistent. To explore how hypertension is treated and the possible relationship to polypharmacy, I designed two cross sectional studies: a cohort of 214 nursing home patients where I found that patients with treated systolic blood pressure (SBP) <128 mmHg had a RR 1.77 (1.07-2.96) of being prescribed ≥9 medications. And, a cohort of 25,737 community-dwelling people ≥70 years old, where I found treated SBP <120 or DBP <70 mmHg also had significant associations with increased prescribing. Hypothesis # 2: Treatment of hypertension to SBP <120 mmHg is associated with increased harm, specifically, an increase in incident dementia. Some observational studies have found an increased risk of dementia with lower SBP. I created a cox proportional hazards model to examine risk for incident dementia and associations with various treatment intensities of hypertension in a large cohort of Canadians and found a significant decreased risk of incident dementia for every 1 mmHg increase in SBP, HR 0.991 (95%CI 0.987-0.995, p = <.0001). Conclusion: In the populations studied, increased treatment of hypertension is associated with increased polypharmacy and treatment of SBP to <120 mmHg is associated with an increased hazard ratio for incident dementia. Treatment intensity, and the use of upper and lower treatment thresholds, may aid future polypharmacy research and general clinical care of older Canadians.

Item Citations and Data


Attribution-NonCommercial-NoDerivatives 4.0 International