REACT-AUS: REsistant And Hard-to-Control HyperTension in AUStralia

Study type

• Study topic:
  Disease /health condition

  Human medicinal product
• Study topic, other:
  Chronic obstructive pulmonary disease (COPD)
• Study type:
  Non-interventional study
• Scope of the study:
  Disease epidemiology

  Drug utilisation

  Hypothesis generation (including signal detection)
• Data collection methods:
  Primary data collection

Non-interventional study

• Non-interventional study design:
  Cohort

Study drug and medical condition

• Medicinal product name, other:
  All antihypertensive medications, including alpha-2 adrenergic receptor agonists, angiotensin-converting enzyme inhibitors, angiotensin II receptor blockers; angiotensin receptor-neprilysin inhibitors; calcium channel blockers, mineralocorticoid receptor antagonists; diuretics; vasodilators
• Anatomical Therapeutic Chemical (ATC) code:
  (C02) ANTIHYPERTENSIVES

  ANTIHYPERTENSIVES
• Medical condition to be studied:
  Hypertension

Population studied

• Short description of the study population:
  All adults (≥18 years and <85 years) with high blood pressure measurement (SBP ≥140mmHg and/or DBP≥90mmHg) with ≥2 antihypertension treatments in the previous 1–4 months between 2006 and 2025 will be identified. For hard-to-control hypertension, index date will be the first date of a high blood pressure measurement with ≥2 antihypertensive therapies in the previous 1–4 months. For resistant hypertension, index date will be the first date of a high blood pressure measurement with ≥3 antihypertensive therapies in the previous 1–4 months. The same patient can be included as having hard-to-control and resistant hypertension where they step up from 2 antihypertensive therapies, but their blood pressure remains uncontrolled.
• Age groups:
  • Adult and elderly population (≥18 years)

    • Adults (18 to < 65 years)

      • Adults (18 to < 46 years)
      • Adults (46 to < 65 years)
    • Elderly (≥ 65 years)

      • Adults (65 to < 75 years)
      • Adults (75 to < 85 years)
      • Adults (85 years and over)
• Special population of interest, other:
  People with hypertension

Study design details

• Study design:
  Observational cohort study using the Optimum Patient Care Research Database Australia (OPCRDA).
• Main study objective:
  To quantify the prevalence of hard-to-control/resistant hypertension and explore factors that drive treatment choices
• Setting:
  This observational cohort study uses data from Australian primary care electronic medical records from the Optimum Patient Care Research Database Australia (OPCRDA). The OPCRDA is a real-world, longitudinal, research database that is maintained by Optimum Patient Care Australia (OPCA). It contains anonymised health data from over one million patients from primary care across Australia.
• Comparators:
  Comparators within subgroups of covariates (e.g. treatments) will be investigated but all patients will have hard-to-control/resistant hypertension.
• Outcomes:
  1. Hard-to-control hypertension ; 2. Resistant hypertension ; 3. Individual treatments prescribed for hard-to-control hypertension ; 4. Individual treatments prescribed for resistant hypertension ; 5. Antihypertensive treatment classes for hard-to-control hypertension ; 6. Antihypertensive treatment classes for resistant hypertension ; 7. Time since first high blood pressure measurement (i.e. burden of hypertension)
• Data analysis plan:
  The baseline characteristics of the study population will be described. ; ; Aim 1: Prescribing patterns and treatment trajectories of hypertension patients ; ; Individual antihypertensive therapies, antihypertensive drug classes and antihypertensive drug class regimens prescribed for patients with hard-to-control and resistant hypertension will be investigated during the 12-month follow-up period using proportions and Wilson confidence intervals. We will investigate if the distribution of medications has changed over calendar time to evaluate potential cohort effects. We will also compare treatment choices with guidelines. These approaches will be mainly descriptive. ; ; Aim 2: Factors driving treatment choices for hard-to-control/resistant hypertension ; ; The relationship between the most common individual antihypertensive regimens (outcome measure) for hard-to-control/resistant hypertension, blood pressure control status, clinical characteristics, comorbidities and concomitant medications, patient adherence and time to step-up to add-on therapies will be investigated using multi-level generalised linear models, allowing for clustering by practice ID (random effect). ; ; Aim 3: Prevalence of hard-to-control/resistant hypertension and length of time with hypertension before meeting hard-to-control/resistant status ; ; Additional objectives will be achieved using descriptive statistics of the number and characteristics of patients with hard-to-control hypertension and resistant hypertension, also looking at any differences across time and by age/gender distributions. Among those who have been clinically active (consultation/prescription) in previous 5 years (2011 onwards), we will investigate length of time (categorised) between first hypertension measurement and resistant/hard-to-control status and from hard-to-control to resistant hypertension status.
• Summary results:
  Findings from this study will be reported and presented at the Pharmaceutical Benefits Advisory Committee (PBAC) by May 2026.