Studies on idiopathic pulmonary fibrosis (IPF) epidemiology
| First author [ref.] | Country and study period | Study methods and case definition | Study population | Age limitations | Rates per 100 000 person-years |
| Mannino [31] | USA, 1979–1991 | Source: death certificate reports compiled by the National Center for Health Statistics | US population (N/A) | None | Mortality for PF: 330 (95% CI N/A) |
| Cases identified based on: ICD-8CM codes and ICD-9CM codes (515, 516.3), used to identify PF | |||||
| Coultas [11] | USA, 1988–1990 | Source: population-based ILD registry, clinical and administrative databases Cases identified based on: physician diagnosis, following a common guideline | 480 577 (year: 1990) | ≥18 years (stratified data for ≥35 years) | Prevalence of IPF: Males 20.2 (95% CI N/A); Females 13.2 (95% CI N/A) Incidence of IPF: Males: 10.7 (95% CI N/A); Females: 7.4 (95% CI N/A) |
| Olson [9] | USA, 1992–2003 | Source: death certificate reports compiled by the National Center for Health Statistics | US population (N/A) | None (stratified data for ≥45 years) | Mortality for PF: 508 (95% CI N/A) |
| Cases identified based on: ICD-9CM codes (515, 516.3) and ICD-10CM codes (J84.1), used to identify PF | |||||
| Raghu [ 12 ] | USA, 1996–2000 | Source: healthcare claims databases of a health plan Cases identified based on: ICD9-CM codes | 2 149 054 | ≥18 years | Broad case definition: Prevalence of IPF 42.7 (95% CI N/A); Incidence of IPF 16.3 (95% CI N/A) |
| (516.3), with two algorithms (broad case definition# and narrow case definition¶) | Narrow case definition: Prevalence of IPF 14.0 (95% CI N/A); Incidence of IPF 6.8 (95% CI N/A) | ||||
| Fernández Pérez [13] | USA, 1997–2005 | Source: clinical and administrative database of medical care Cases identified based on: ICD9-CM codes (516.3), hospital international classification of diseases-adapted codes (517, 519), physician diagnosis, ATS/ERS consensus 2002 [37] Two algorithms (narrow case definition+ and broad case definition§) | ∼128 000 (all ages) | ≥50 years | Broad case definition: Prevalence of IPF 63.0 (95% CI 36.4–89.6); Incidence of IPF 17.4 (95% CI 12.4–22.4) Narrow case definition: Prevalence of IPF 27.9 (95% CI 10.4–45.4); Incidence of IPF 8.8 (95% CI 5.3–12.4) |
| Raghu [14] | USA, 2000–2011 | Source: administrative claims from a 5% random sample of Medicare beneficiaries Cases identified based on: ICD9-CM codes (516.3), with two algorithms (broad case definition# and narrow case definition¶) | 2 871 436 | ≥65 years | Broad case definition: Prevalence of IPF 82.6 (95% CI N/A) in 2001; 233.3 (95% CI N/A) in 2011 Incidence of IPF 31.1 (95% CI N/A) in 2001; 43.0 (95% CI N/A) in year 2011 |
| Narrow case definition: Prevalence of IPF 30.5 (95% CI N/A) in 2001; 145.7 (95% CI N/A) in 2011 Incidence of IPF 15.9 (95% CI N/A) in 2001; 31.1 (95% CI N/A) in 2011 | |||||
| Navaratnam [24] | UK, 1968–2009 | Source: the Health Improvement Network database (primary care), death certificates from the Office for National Statistics | Population of the study area (N/A) | ≥40 years | Incidence of IPF 2000–2009: 7.44 (95% CI 7.12–7.77) |
| Cases identified based on: ICD-8CM codes (517), ICD-9CM codes (516.3, 515), ICD-10CM codes (J84.1), the Read codes (H563.00, H563.11, H563.12, H563100, H563z00) | Mortality for IPF 1968–2008: 2.54 (95% CI 2.52–2.56) | ||||
| Kolek [15] | Czech Republic, 1981–1990 | Source: retrospective observational study in 24 centres | 4 033 010 (year 1990) | None | Prevalence of CFA 6.5 (95% CI N/A) in 1981; 12.1 (95% CI N/A) in 1990 |
| Cases identified based on: physician diagnosis of CFA | Incidence of CFA 0.74 (95% CI N/A) in 1981; 1.28 (95% CI N/A) in 1990 | ||||
| von Plessen [19] | Norway, 1984–1998 | Source: hospital records Cases identified based on: ICD-8CM codes (517, 517.00, 517.01, 517.09) and ICD-9CM codes (515, 516.3, 516.8, 516.9), used to identify CFA | 254 999 (year 1999) | ≥16 years | All CFA cases: Prevalence 23.4 (95% CI 14.9–33.0) Incidence 4.3 (95% CI N/A) CFA cases after clinical validation: Prevalence 11.4 (95% CI N/A) Incidence 2.7 (95% CI N/A) |
| Gribbin [23] | UK, 1991–2003 | Source: the Health Improvement Network database (primary care) | 1 555 152 (all ages) | ≥40 years | Incidence of IPF 4.6 (95% CI 4.3–4.9) |
| Cases identified based on: physician diagnosis | |||||
| Thomeer [16] | Belgium, 1992–1996 | Source: population-based ILDs registry in 20 centres | 5 768 925 | None | Prevalence of IPF 1.25 (95% CI N/A) |
| Incidence of IPF 0.22 (95% CI N/A) | |||||
| Cases identified based on: physician diagnosis, ATS/ERS consensus 2000 [36] | |||||
| Hodgson [18] | Finland, 1997–1998 | Source: pulmonary clinic databases nationwide (29 clinics) | 5 170 000 | None | Prevalence of IPF 16–18 (95% CI N/A) |
| Cases identified based on: ICD10-CM codes (J84.1), physician diagnosis, ATS/ERS guidelines 2000 [36] | |||||
| Tinelli [21] | Italy, 1998–2005 | Source: national register for ILDs, voluntary participation | N/A | None | Number of IPF cases: 864, rates N/A |
| Cases identified based on: physician diagnosis | |||||
| Xaubet [20] | Spain, 2000–2001 | Source: population-based ILDs registry in 23 respiratory centres | 6 700 000 | None | Incidence of ILDs 7.6 (95% CI N/A) IPF constituted 38.6% of cases |
| Cases identified based on: physician diagnosis, ATS/ERS consensus 2000 [36] and 2002 [37] | |||||
| Hyldgaard [32] | Denmark, 2003–2009 | Source: clinical and administrative databases, patients who were diagnosed with ILDs | Population of the study area (N/A) | None | Incidence of ILDs 4.1 (95% CI N/A) IPF constituted 28.0% of cases |
| Cases identified based on: ICD10-CM codes, validation with ATS/ERS consensus 2011 [1] | |||||
| Karakatsani [22] | Greece, 2004 | Source: ad hoc questionnaires for investigating incidence and prevalence of IPF | ∼3 360 000 | ≥16 years | Prevalence of IPF 3.38 (95% CI N/A) |
| Incidence of IPF 0.93 (95% CI N/A) | |||||
| Cases identified based on: physician diagnosis, ATS/ERS consensus 2002 [37] | |||||
| Agabiti [25] | Italy, 2005–2009 | Source: hospital admissions database, mortality database of the regional public health service in Lazio | 4 727 710 | ≥18 years | All IPF cases: Prevalence 25.6 (95% CI 25.1–26.2) Incidence 7.5 (95% CI 7.3–7.7) |
| IPF “confident” definition after hospital chart audit: Prevalence 31.6 (95% CI 30.9–32.2) Incidence 9.3 (95% CI 9.2–9.4) | |||||
| Cases identified based on: ICD9-CM codes (516.3) | |||||
| Musellim [33] | Turkey, 2007–2009 | Source: ad hoc questionnaires, prospective study (31 centres in 19 cities) | N/A | None | Incidence of ILDs 25.8 (95% CI N/A) IPF constituted 19.9% of cases |
| Cases identified based on: physician diagnosis, ATS/ERS guidelines 2002 [37], to identify ILDs | |||||
| Behr [30] | Germany, 2012–2014 | Source: national register for IPF (19 centres) | N/A | ≥18 years | Number of IPF cases: 502 Number of prevalent IPF cases: 331 Number of incident IPF cases: 171 Rates N/A |
| Cases identified based on: physician diagnosis | |||||
| Lai [34] | Taiwan, 1997–2007 | Source: administrative databases from Bureau of National Health Insurance and Ministry of the Interior, regarding health services and deaths | 2 619 534 (all ages) | ≥18 years | Broad case definition: Prevalence of IPF 0.7 (95% CI N/A) in 1998; 6.4 (95% CI N/A) in 2007 Incidence of IPF 0.6 (95% CI N/A) in 1998; 1.4 (95% CI N/A) in 2007 |
| Cases identified based on: ICD9-CM codes (516.3), with two algorithms (broad case definition# and narrow case definition¶) | |||||
| Narrow case definition: Prevalence of IPF 0.5 (95% CI N/A) in 1998; 4.9 (95% CI N/A) in 2007 Incidence of IPF 0.5 (95% CI N/A) in 1998; 1.2 (95% CI N/A) in 2007 | |||||
| Natsuizaka [27] | Japan, 2003–2007 | Source: clinical database of patients with IPF and the Certificate of Medical Benefit | 5 572 770 | None | Prevalence of IPF 10 (95% CI N/A) |
| Incidence of IPF 2.23 (95% CI N/A) | |||||
| Cases identified based on: physician diagnosis, ATS/ERS guidelines 2000 [36] | |||||
| Ohno [26] | Japan, 2005 | Source: clinical database of patients with IIP and the Certificate of Medical Benefit | 127 756 815 | None | Prevalence of IIP 3.44 (95% CI N/A) Number of IPF prevalent cases: 1322 Number of IPF incident cases: 545 |
| Cases identified based on: physician diagnosis | |||||
| Hutchinson [35] | Worldwide, 1999–2012 | Source: mortality data from national statistics agencies | N/A | None | Mortality for IPF 2010 J84: between 4.60 (Sweden) and 9.93 (Japan) (95% CI N/A) J84.1: between 4.63 (Spain) and 7.19 (England and Wales) (95% CI N/A) |
| Cases identified based on: ICD10-CM codes (J84 and J84.1) |
ICD: International Classification of Diseases; PF: pulmonary fibrosis; N/A: not available; ILD: interstitial lung disease; ATS: American Thoracic Society; ERS: European Respiratory Society; CFA: cryptogenic fibrosing alveolitis; IIP: idiopathic interstitial pneumonia. #: age ≥18 years, at least one medical claim with a diagnosis code for IPF (ICD-9-CM 516.3), no medical claims with a diagnosis code for any other ILDs on or after the date of the last medical claim with a diagnosis code for IPF; ¶: met broad case definition (see #) plus had at least one medical claim with a procedure code for surgical lung biopsy, transbronchial lung biopsy or high-resolution computed tomography (HRCT) on or before the date of the last medical claim with a diagnosis code for IPF; +: usual interstitial pneumonia (UIP) on surgical lung biopsy specimen or a definite UIP pattern on a HRCT image; §: UIP on surgical lung biopsy specimen or a definite or possible UIP pattern on a HRCT image.