Incidence of idiopathic pulmonary fibrosis (IPF) in studies using large databases

First author [ref.]YearLocationYears studiedData source typeCondition studiedCase definitionPopulation demographicsIncidence per 100 000 per year#Rate type
Large database studies
  Maher [7]2013UK2000–2012Nationwide primary care database (CPRD)IPFNANA8.65Crude
  Navaratnam [8]2011UK2000–2008Nationwide primary care database (THIN)IPFICD-9 codes for IFA (515) and PF (516.3)Overall population of the UK7.44Crude
  Kornum [9]2008Denmark1995–2000Nationwide health databaseIPF (and ILD)ICD-10 J84.1Overall population of Denmark7.27
2001–2005Nationwide health databaseIPF (and ILD)ICD-10 J84.15.28
  Gribbin [10]2006UK1991–2003Nationwide primary care database (THIN)IPFRead codes for CFA, IFAOverall THIN population4.6Crude
 North America
  Ley [11]2017NC, USA2000–2014Health insurance plan databaseIPFICD-9 code 516.3, or ICD-9-CM code 516.31Overall health insurance plan population6.8 (overall)
3.1 (per 100 000 person-years)
  Esposito [12]2015USA2006–2012Nationwide HealthCore Integrated Research DatabaseIPFICD-9-CM code 516.3Health plan members; age-adjusted value applicable to overall US population31.9 (broad case definition)
14.6 (per 100 000 person-years)
Age-adjusted, PPV-corrected
  Raghu [13]2014USA2001–2011Medicare database; 5% random sampleIPFICD-9-CM 516.3 and 515
ICD-9-CM 516.3
Medicare population aged ≥65 years93.7 (overall)
31.1–43.0 (broad)
15.9–31.1 (narrow)
Crude, patients aged >65 years
Algorithm-defined exclusions, patients aged >65 years
  Fernández Pérez [14]2010Olmsted County, MN, USA1997–2005Rochester Epidemiology Project (medical record linkage system for healthcare providers)IPFICD-9 code 516.3
Hospital International Classification of Diseases-Adapted codes 517 and 519
Olmsted County population aged ≥50 years; data adjusted for applicability to overall US white population8.8 (narrow)
17.4 (broad)
Age-adjusted, sex-adjusted
  Ehrlich [15]2010CA, USA1996–2005Health insurance plan databaseIPF
ICD-9 516.3/515Health plan population; data adjusted for applicability to overall US population aged ≥18 years9 (non-diabetics)
14 (diabetics)
Age-adjusted, by diabetic status
  Raghu [16]2006USA1996–2000Health claims databaseIPFICD-9 516.3Health claims database population; data adjusted for applicability to overall US population16.3 (broad)
6.8 (narrow)
 South America
  Rufino [17]2013Brazil1996–2010Ministry of Health dataIPFICD-10 J84.10.48Crude
  Han [18]2013South Korea1992–2010Healthcare claims from insurance medical cohortIPFNANA4.16 (broad)
1.84 (narrow)
Crude, patients >30 years
  Lai [19]2012Taiwan1997–2007Health insurance database/ government recordsIPFICD-9 516.3Population of the Taiwan National Health Insurance database1.4 (broad)
1.2 (narrow)
  Natsuizaka [20]2014Hokkaido prefecture, Japan2003–2007Ministry of Health, Labor and Welfare dataIPFATS/ERS consensus classificationOverall population of Hokkaido2.23Crude

International Classification of Diseases (ICD) codes are presented as ICD-nth revision, clinical modification (CM). ICD-10 code J84.1 is currently the most specific code for IPF but may include other idiopathic interstitial pneumonia (IIP). ICD-9 code 516.3 is roughly equivalent; code 515 is “post-inflammatory fibrosis”. Broad criteria were: one or more claims with a diagnostic code for IPF, but no claims for another diagnostic code for interstitial lung disease (ILD). Narrow criteria were: as for broad criteria, with a relevant diagnostic test on or before their first diagnosis date. Broad and narrow criteria were based on the 2002 American Thoracic Society (ATS)/European Respiratory Society (ERS) guidelines [21]. Probable cases were based on criteria from [22]: received a diagnosis of ILD from a rheumatologist or pulmonary physician; or ILD was the primary discharge diagnosis. Definite cases had a confirmatory diagnosis within 90 days. CPRD: Clinical Practice Research Datalink; NA: not available; THIN: The Health Improvement Network; IFA: idiopathic fibrosing alveolitis; PF: pulmonary fibrosis; CFA: cryptogenic fibrosing alveolitis; PPV: positive-predictive value; IIP: idiopathic interstitial pneumonia; IPF: idiopathic pulmonary fibrosis. #: average incidence for the time period available; latest incidence stated where no average was given, incidence extrapolated from ILD data where percentage of IPF cases was given; : abstract only. Reproduced and modified from [23] with permission.