Re-evaluation of diagnostic parameters is crucial for obtaining accurate data on idiopathic pulmonary fibrosis.
BACKGROUND
The FinnishIPF registry is a prospective, longitudinal national registry study on the epidemiology of idiopathic pulmonary fibrosis (IPF). It was designed to describe the characteristics, management and prognosis of prevalent and incident IPF patients. The study was initiated in 2012.


METHODS
We present here results limited to five university hospitals. Patients with IPF were screened from hospital registries using ICD-10 diagnosis codes J84.1 and J84.9. All patients who gave informed consent were included and evaluated using novel diagnostic criteria. Point prevalence on the 31(st) of December in 2012 was calculated using the reported population in each university hospital city as the denominator.


RESULTS
Patients with ICD-10 codes J84.1 and J84.9 yielded a heterogeneous group - on the basis of patient records assessed by pulmonologists only 20-30 % of the cases were IPF. After clinical, radiological and histological re-evaluation 111 of 123 (90 %) of patients fulfilled the clinical criteria of IPF. The estimated prevalence of IPF was 8.6 cases/100 000. 60.4 % were men. Forty four percent of the patients were never-smokers. At diagnosis, the patients' mean age was 73.5 years and mean FVC was 80.4 % and DLCO 57.3 % of predicted.


CONCLUSIONS
Our results suggest that hospital registries are inaccurate for epidemiological studies unless patients are carefully re-evaluated. IPF is diagnosed in Finland at a stage when lung function is still quite well preserved. Smoking in patients with IPF was less common than in previous reports.
Division of Medicine, Pulmonary Diseases, Turku University Hospital, University of Turku, Turku, Finland. jakrja@utu.fi.|Department of Pulmonary Diseases and Clinical Allergology, University of Turku, Turku, Finland. jakrja@utu.fi.
Jaana
J
Kaunisto
HUS Medical Imaging Center, Radiology, University of Helsinki and Helsinki University Hospital, Helsinki, Finland. katariina.kelloniemi@hus.fi.
K
K
Kelloniemi
University of Helsinki and Helsinki University Central Hospital, Heart and Lung Center, Helsinki, Finland. eva.sutinen@helsinki.fi.
E
E
Sutinen
University of Helsinki and Helsinki University Central Hospital, Heart and Lung Center, Helsinki, Finland. ulla.hodgson@hus.fi.
U
U
Hodgson
HUS Medical Imaging Center, Radiology, University of Helsinki and Helsinki University Hospital, Helsinki, Finland. anneli.piilonen@hus.fi.
A
A
Piilonen
Department of Internal Medicine, Respiratory Diseases, University of Oulu, Oulu, Finland. Riitta.Kaarteenaho@oulu.fi.|Medical Research Center Oulu, Respiratory Research Unit, Oulu University Hospital, Oulu, Finland. Riitta.Kaarteenaho@oulu.fi.|Unit of Medicine and Clinical Research, Pulmonary Division, University of Eastern Finland, Kuopio, Finland. Riitta.Kaarteenaho@oulu.fi.|Center for Medicine and Clinical Research, Division of Respiratory Medicine, Kuopio University Hospital, Kuopio, Finland. Riitta.Kaarteenaho@oulu.fi.
R
R
Kaarteenaho
Medical Research Center Oulu, Respiratory Research Unit, Oulu University Hospital, Oulu, Finland. riitta.makitaro@ppshp.fi.|Department of Internal Medicine, Respiratory Diseases, Institute of Clinical Medicine, University of Oulu, Oulu, Finland. riitta.makitaro@ppshp.fi.
R
R
Mäkitaro
Center for Medicine and Clinical Research, Division of Respiratory Medicine, Kuopio University Hospital, Kuopio, Finland. minna.purokivi@kuh.fi.
M
M
Purokivi
Department of Pathology, Oulu University Hospital and Oulu University, Oulu, Finland. Elisa.Lappi-Blanco@ppshp.fi.|Medical Research Center Oulu, Oulu, Finland. Elisa.Lappi-Blanco@ppshp.fi.
E
E
Lappi-Blanco
Department of Respiratory Medicine, Tampere University Hospital, Tampere, Finland. seppo.saarelainen@pshp.fi.
S
S
Saarelainen
Department of Respiratory Medicine, Seinäjoki Central Hospital, Seinäjoki, Finland. hannu.kankaanranta@epshp.fi.|Department of Respiratory Medicine, University of Tampere, Tampere, Finland. hannu.kankaanranta@epshp.fi.
H
H
Kankaanranta
City Hospital of Oulu and Hoitoketju Coronaria Oy, Oulu, Finland. arja.mursu@fimnet.fi.
A
A
Mursu
University of Tampere, School of Health Sciences, Tampere, Finland. merja.kanervisto@uta.fi.
M
M
Kanervisto
University of Turku, Turku, Finland. eija-riitta.salomaa@fimnet.fi.
E-R
ER
Salomaa
University of Helsinki and Helsinki University Hospital, Heart and Lung Center and Transplantation laboratory, Helsinki, Finland. marjukka.myllarniemi@helsinki.fi.
M
M
Myllärniemi
D000368:Aged; D000068598:Data Accuracy; D005260:Female; D005387:Finland / Q000453:epidemiology; D005500:Follow-Up Studies; D006785:Hospitals, University; D006801:Humans; D054990:Idiopathic Pulmonary Fibrosis / Q000175:diagnosis* / Q000453:epidemiology; D015994:Incidence; D008297:Male; D008499:Medical Records; D015995:Prevalence; D011379:Prognosis; D011446:Prospective Studies; D012042:Registries; D014057:Tomography, X-Ray Computed