Grant: Project Grant

Hypertension affects >6 million Canadians and is a leading cause of heart attacks, strokes, and death. 1 in 4 of people with hypertension have uncontrolled high blood pressure despite taking multiple drugs. This is called resistant hypertension, and is often due to unrecognized and untreated causes of elevated blood pressure. One of the most common causes of resistant hypertension is primary aldosteronism (PA), a condition where the adrenal glands make an excessive amount of a hormone called aldosterone, leading to high blood pressure. PA is important to recognize because highly effective treatment is available. However, PA is challenging to diagnose. The current process for diagnosing PA is lengthy and expensive. The first step involves a screening blood test. Patients with positive screens are sent for costly "confirmatory" testing. Further invasive testing and definitive treatment are offered to those confirmed to have the diagnosis. However, the usefulness of confirmatory testing is unclear. It is uncertain how often "normal" or "abnormal" results correspond with the truth. It is unresolved whether confirmatory testing is needed, or whether it merely adds an unnecessary step to an already complicated diagnostic pathway. In an effort to better understand the role of confirmatory testing for people with resistant hypertension, we propose to evaluate the performance of confirmatory testing compared to an established gold-standard. Individuals suspected of having PA will receive confirmatory testing and definitive treatment. The outcomes will be compared to determine how many people with PA are misclassified with confirmatory testing. We will examine for potential differences in responses between women and men. This study will help healthcare providers understand the strengths and limitations of confirmatory testing. Our results may help facilitate improved diagnosis and access to effective treatment for individuals with high blood pressure.