Incidence of idiopathic pulmonary fibrosis (IPF) in studies using large databases
| First author [ref.] | Year | Location | Years studied | Data source type | Condition studied | Case definition | Population demographics | Incidence per 100 000 per year# | Rate type |
| Large database studies | |||||||||
| Europe | |||||||||
| Maher [7]¶ | 2013 | UK | 2000–2012 | Nationwide primary care database (CPRD) | IPF | NA | NA | 8.65 | Crude |
| Navaratnam [8] | 2011 | UK | 2000–2008 | Nationwide primary care database (THIN) | IPF | ICD-9 codes for IFA (515) and PF (516.3) | Overall population of the UK | 7.44 | Crude |
| Kornum [9] | 2008 | Denmark | 1995–2000 | Nationwide health database | IPF (and ILD) | ICD-10 J84.1 | Overall population of Denmark | 7.27 4.17 | Crude Age-adjusted |
| 2001–2005 | Nationwide health database | IPF (and ILD) | ICD-10 J84.1 | 5.28 2.91 | Crude Age-adjusted | ||||
| Gribbin [10] | 2006 | UK | 1991–2003 | Nationwide primary care database (THIN) | IPF | Read codes for CFA, IFA | Overall THIN population | 4.6 | Crude |
| North America | |||||||||
| Ley [11] | 2017 | NC, USA | 2000–2014 | Health insurance plan database | IPF | ICD-9 code 516.3, or ICD-9-CM code 516.31 | Overall health insurance plan population | 6.8 (overall) 3.1 (per 100 000 person-years) | PPV-corrected |
| Esposito [12] | 2015 | USA | 2006–2012 | Nationwide HealthCore Integrated Research Database | IPF | ICD-9-CM code 516.3 | Health plan members; age-adjusted value applicable to overall US population | 31.9 (broad case definition) 14.6 (per 100 000 person-years) | Age-adjusted, PPV-corrected |
| Raghu [13] | 2014 | USA | 2001–2011 | Medicare database; 5% random sample | IPF | ICD-9-CM 516.3 and 515 ICD-9-CM 516.3 | Medicare population aged ≥65 years | 93.7 (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] | 2010 | Olmsted County, MN, USA | 1997–2005 | Rochester Epidemiology Project (medical record linkage system for healthcare providers) | IPF | ICD-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 population | 8.8 (narrow) 17.4 (broad) | Age-adjusted, sex-adjusted |
| Ehrlich [15] | 2010 | CA, USA | 1996–2005 | Health insurance plan database | IPF PF | ICD-9 516.3/515 | Health plan population; data adjusted for applicability to overall US population aged ≥18 years | 9 (non-diabetics) 14 (diabetics) | Crude Age-adjusted, by diabetic status |
| Raghu [16] | 2006 | USA | 1996–2000 | Health claims database | IPF | ICD-9 516.3 | Health claims database population; data adjusted for applicability to overall US population | 16.3 (broad) 6.8 (narrow) | Age-adjusted |
| South America | |||||||||
| Rufino [17]¶ | 2013 | Brazil | 1996–2010 | Ministry of Health data | IPF | ICD-10 J84.1 | 0.48 | Crude | |
| Asia | |||||||||
| Han [18]¶ | 2013 | South Korea | 1992–2010 | Healthcare claims from insurance medical cohort | IPF | NA | NA | 4.16 (broad) 1.84 (narrow) | Crude, patients >30 years |
| Lai [19] | 2012 | Taiwan | 1997–2007 | Health insurance database/ government records | IPF | ICD-9 516.3 | Population of the Taiwan National Health Insurance database | 1.4 (broad) 1.2 (narrow) | Crude |
| Natsuizaka [20] | 2014 | Hokkaido prefecture, Japan | 2003–2007 | Ministry of Health, Labor and Welfare data | IPF | ATS/ERS consensus classification | Overall population of Hokkaido | 2.23 | Crude |
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.