Association of alpha-1 blocker (ɑ-1B) on coronavirus disease (COVID-19) susceptibility and severity

Study type

• Study topic:
  Human medicinal product

  Disease /health condition
• Study type:
  Non-interventional study
• Scope of the study:
  Disease epidemiology

  Drug utilisation
• Data collection methods:
  Secondary data collection

Non-interventional study

• Non-interventional study design:
  Cohort

Study drug and medical condition

• Anatomical Therapeutic Chemical (ATC) code:
  (G04C) DRUGS USED IN BENIGN PROSTATIC HYPERTROPHY
• Medical condition to be studied:
  Benign prostatic hyperplasia

Population studied

• Short description of the study population:
  The cohort will consist of adult male patients aged 18 years and over who receive at least one eligible prescription for an exposure drug between 1st November 2019 and 31st January 2020 (with index date set as the last prescription in this window) and are observable in each database for at least one year prior to the index date. To minimize confounding by indication, patients are required to have a history of benign prostatic hyperplasia at any point prior to or including the index date and to be prescribed medication (ɑ-1B or 5-ɑRI) as treatment. Cohort exit will be the earliest of: the occurrence of an outcome event; the end of exposure; death; loss or deregistration from the database; or date of last data collection.
• Age groups:
  Adults (18 to < 46 years)

  Adults (46 to < 65 years)

  Adults (65 to < 75 years)

  Adults (75 to < 85 years)

  Adults (85 years and over)
• Special population of interest:
  Other
• Special population of interest, other:
  Benign prostate hyperplasia patients
• Estimated number of subjects:
  20000

Study design details

• Main study objective:
  To estimate the association between prevalent use of alpha-1 blockers (ɑ-1B) and the risk of contracting COVID-19 infection and of subsequently requiring hospitalization and intensive services such as mechanical ventilation.
• Outcomes:
  The primary outcomes of interest will be an incident of COVID-19 diagnosis or SARS-CoV-2 positive test 1) without hospitalization, 2) with hospitalization, and 3) requiring intensive in-patient services such as mechanical ventilation. The detailed definitions of these outcomes are given in Appendix 1.
• Data analysis plan:
  We will estimate the relative risk of each outcome using an on-treatment analysis for the target exposure (ɑ-1B) against the comparator exposure (5-ɑRI) in patients with BPH. We will describe patient characteristics (prevalence) for each cohort comparison and data source. To adjust for measured confounding, propensity score models for each class pair and data source will be created using a data-driven process using regularized logistic regression when target and comparator cohorts contain at least 500 patients within each data source. This process allows the data to decide which combinations of baseline patient characteristics, including demographics and previous conditions, drug exposures, procedures, and health-service-use behaviors are most predictive of treatment assignment. For cohorts with fewer than 500 patients, we will build propensity score models using gender and age categorized in 5-year groups, and index month examining for any heterogeneity.