Multimorbidity and blood pressure control: a cross-sectional analysis among 67,385 adults with hypertension in Canada

Background There has been conflicting evidence on the association between multimorbidity and blood pressure (BP) control. This study aimed to investigate this associations in people with hypertension attending primary care in Canada, and to assess whether individual long-term conditions are associated with BP control. Methods A cross-sectional study in people with hypertension attending primary care in Toronto between January 01 2017 and December 31 2019. Uncontrolled BP was defined as systolic BP≥140 mmHg or diastolic BP≥90 mmHg. A list of 11 a priori selected chronic conditions was used to define multimorbidity. Multimorbidity was defined as having ≥1 long-term condition in addition to hypertension. Logistic regression models were used to estimate the association between multimorbidity (or individual long-term conditions) with uncontrolled BP. Results A total of 67,385 patients with hypertension were included. They had a mean age of 70, 53.1% were female, 80.6% had multimorbidity, and 35.7% had uncontrolled BP. Patients with multimorbidity had lower odds of uncontrolled BP than those without multimorbidity (adjusted OR 0.72, 95% CI 0.68-0.76). Among the long-term conditions, diabetes (aOR 0.73, 95%CI 0.70-0.77), heart failure (aOR 0.81, 95%CI 0.73-0.91), ischemic heart disease (aOR 0.74, 95%CI 0.69-0.79), schizophrenia (aOR 0.79, 95%CI 0.65-0.97), depression/anxiety (aOR 0.91, 95%CI 0.86-0.95), dementia (aOR 0.87, 95%CI 0.80-0.95), and osteoarthritis (aOR 0.89, 95%CI 0.85-0.93) were associated with a lower likelihood of uncontrolled BP. Conclusion We found that multimorbidity was associated with better BP control. Several conditions were associated with better control, including diabetes, heart failure, ischemic heart disease, schizophrenia, depression/anxiety, dementia, and osteoarthritis.