Table 1

Studies reporting IPF prevalence per 100 000 persons by various case definitions

Case definitionsPrevalence estimate (per 100 000 persons)Case descriptionsCountry, author-published year
  • Patients with at least 1 hospitalisation or at least 1 outpatient visits with IPF diagnosis

Italy, Harari,13 2016
  • Patients with at least 1 claim with IPF diagnosis.

USA, Raghu,2 2016
Overall IPF20
  • Patients with at least 1 IPF inpatient claim, or 2 IPF outpatient claims with ICD code with no other ILD claim

USA, Raimundo,14 2016
Overall IPF35
  • IPF diagnostic K codes

South Korea, Lee,15 2016
  • Patients who had a code for IPF with no other ILD

USA, Zhang,16 2021
  • Patients with code of ICD 516.3, patients excluded if they had a claim with code 515 after the last ICD code 516.3

USA, Raghu,2 2016
  • Patients with code ICD code J84.1, cases with diagnosis of another ILD excluded

Canada, Hopkins,17 2016
  • Patients with IPF code and no claims for other ILD diagnosis

Italy, Harari,13 2016
  • Patients with Read codes: H563.00, H563.12, H563300, H563.13, H563100, H563200 and H563.11

UK, Strongman,18 2018
  • Patients that satisfied the broad definition

  • Had 1> claim with procedure code for SLB, TLB or CT thorax

Harari,13 2016
  • Patients who had a code for IPF

  • And if they did not have any other code for an alternative ILD

  • And patients who had procedure code for an SLB or a thorax

Zhang,16 2021
  • Patients with an ICD code of 516.3 and they were excluded if they had a claim with the ICD code 515

  • And further restricted by requiring a claim for an SLB, TLB or CT thorax

USA, Raghu,2 2016
  • Patients with ICD codes J84.1 with no other ILD and excluded cases that did not have chest CT, bronchus or SLB or bronchoscopy

Canada, Hopkins,17 2016
  • ICD, International Classification of Diseases; ILD, interstitial lung disease; IPF, Idiopathic pulmonary fibrosis; SLB, surgical lung biopsy; TLB, transbronchial lung biopsy.