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. ### Competing Interest Statement The authors have declared no competing interest. ### Funding Statement The author(s) received no specific funding for this work. ### Author Declarations I confirm all relevant ethical guidelines have been followed, and any necessary IRB and/or ethics committee approvals have been obtained. Yes The details of the IRB/oversight body that provided approval or exemption for the research described are given below: This study was approved by the Research Ethics Board at the University of Toronto (protocol number 00043354). All participating Primary Care Providers provided written informed consent for the collection and analysis of their de-identified EMR data at UTOPIAN; patients could opt out if they so chose. This model was approved by the Research Ethics Board and is consistent with Ontario's privacy legislation (Personal Health Information Protection Act, section 44). I confirm that all necessary patient/participant consent has been obtained and the appropriate institutional forms have been archived, and that any patient/participant/sample identifiers included were not known to anyone (e.g., hospital staff, patients or participants themselves) outside the research group so cannot be used to identify individuals. Yes I understand that all clinical trials and any other prospective interventional studies must be registered with an ICMJE-approved registry, such as ClinicalTrials.gov. I confirm that any such study reported in the manuscript has been registered and the trial registration ID is provided (note: if posting a prospective study registered retrospectively, please provide a statement in the trial ID field explaining why the study was not registered in advance). Yes I have followed all appropriate research reporting guidelines, such as any relevant EQUATOR Network research reporting checklist(s) and other pertinent material, if applicable. Yes The data may contain patient-related information, and therefore due to privacy concerns, has not been made publicly available. The data that was used in this study is available from UTOPIAN at the Department of Family and Community Medicine, Temerty Faculty of Medicine, University of Toronto, following Research Ethics Board approval; please contact dfcm.utopian{at}utoronto.ca