Persistence and adherence to novel systemic pharmacological treatment of moderate to severe psoriasis vulgaris and psoriatic arthritis – A register-based cohort study in Finland and Sweden

Study type

• Study type:
  Non-interventional study
• Scope of the study:
  Drug utilisation

  Effectiveness study (incl. comparative)

Non-interventional study

• Non-interventional study design:
  Cohort

Study drug and medical condition

• Anatomical Therapeutic Chemical (ATC) code:
  (L04AA32) apremilast

  apremilast

  (L04AB01) etanercept

  etanercept

  (L04AB04) adalimumab

  adalimumab

  (L04AB05) certolizumab pegol

  certolizumab pegol

  (L04AC05) ustekinumab

  ustekinumab

  (L04AC10) secukinumab

  secukinumab

  (L04AC12) brodalumab

  brodalumab

  (L04AC13) ixekizumab

  ixekizumab

  (L04AC16) guselkumab

  guselkumab

  (L04AC17) tildrakizumab

  tildrakizumab
• Medical condition to be studied:
  Psoriasis

Population studied

• 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)
• Estimated number of subjects:
  17000

Study design details

• Main study objective:
  The main aim of this study is to investigate the persistence and adherence of drugs dispensed from community pharmacies for patients with moderate to severe psoriasis vulgaris.
• Outcomes:
  The primary outcomes of this study are persistence, proportion of persistent patients, time to non-persistence, hazard ratios associated with non-persistence, adherence, proportion of adherent patients, non-adherence, and odds ratios associated with non-adherence. The secondary outcomes of this study are patient characteristics (e.g. sociodemographic data, comorbidities, resource utilization, and prior use of conventional systemic treatment for psoriasis vulgaris) for persons initiating treatment with each study drug, and treatment patterns, including treatment gaps, switching, and restart, during the study period.
• Data analysis plan:
  All dispensations of the study drugs during the study period will be included in the analyses. Drug supply will be defined for each dispensation on the basis of number and contents of dispensed package(s) and the dosage instructions according to the summary of product characteristics for the particular drug. MPR, based on the drug supplies, will be used to measure drug adherence. Continuous exposure periods will be defined on the basis of drug supplies and by applying more detailed rules for times when drug exposure periods end. The continuous exposure periods will be used to define PDC by each drug, and to determine treatment persistence. The characteristics of patients initiating treatment with study drugs will be described. Adherence and persistence will be described and compared across study drugs using regression models. Rates of drug switches, restarts, treatment gaps and number and duration of treatment lines will be investigated. Various sensitivity analyses will be performed.