The importance of applying diagnostic criteria from consensus 2011 to diagnose idiopathic pulmonary fibrosis (IPF) in a referral site

This study was aimed to determine the frequency of idiopathic pulmonary fibrosis (IPF) diagnosis in different clinical services in the Instituto Nacional de Enfermedades Respiratorias “Dr. Ismael Cosio Villegas” (INER). Based on 2009-2013 INER biostatistics report, the frequency for IPF was determined. The files of patients with a HRCT compatible and probable to have usual interstitial pneumonia (UIP) were requested, diagnosis was confirmed and clinical, pulmonary function and treatment data of patients with confirmed diagnosis was analysed; the frequency of disease was re-calculated following compliance of criteria from Consensus 2011. Diffuse interstitial lung diseases (ILD) accounted for 8.7% of admissions at INER, with 12.6% of them being diagnosed as IPF, which corresponds to 1.1% of total admissions at INER. Following Consensus 2011, 80 IPF cases were confirmed with the frequency reduced to 4.16% compared to ILD and to 0.36% compared to total admissions. This allowed us detect that there are great problems in diagnosis of IPF due to noncompliance of Consensus 2011 outside the clinical service for interstitial diseases. Correspondence to: Jose Omar Barreto-Rodriguez, Unit of Research, National Institute of Respiratory Diseases Ismael Cosio Villegas, Mexico City, Mexico; E-mail: omar_barreto10@hotmail.com Received: February 09, 2016; Accepted: March 05, 2016; Published: March 08, 2016 Introduction Idiopathic pulmonary fibrosis (IPF) is a diffuse interstitial lung disease with a worst prognosis, with an average survival rate between 3 and 5 years following diagnosis, affecting primarily male population and subjects over 55 years of age [1]. Worldwide incidence is estimated to be 4.3 to 16.3 per 100,000 persons, with prevalence between 13 and 20 per 100,000 persons [2]. Its epidemiologic impact is unknown in Mexico. Its aetiology is unknown and clinically patients show cough without expectoration, dyspnoea, and progressive fatigue for at least 6-month evolution. Diagnose is established based on Consensus 2011 criteria (ATS/ERS/JRS/ ALAT) [1], where a pulmonary fibrosis secondary to other entities such as collagen-vascular diseases, pneumonitis due to hypersensitivity and work-related disease is recommended to be ruled out, additionally to confirmation of diagnosis by a high-resolution computerised tomography (HRCT) with a typical pattern for usual interstitial pneumonia or, if possible, obtaining a histological confirmation for usual interstitial pneumonia pattern by surgical lung biopsy. Also, the lung function should be assessed at diagnosis by spirometry, six minute walking distance test (6MWD), carbon monoxide diffusing capacity test (DLCO), and plethysmography. It is suggested to conduct a follow-up for disease evolution quarterly, by using respiratory function tests (spirometry, 6MWD, DLCO). Unfortunately, currently there is no a curative treatment; thus, it is important to obtain a correct diagnosis because the prognosis is more encouraging for the other ILD, with successful treatment schemes. In May, 2014 the results for two drugs (nintedanib and pirfenidone) were presented, with both delaying the disease progress and having IPF as the unique approved indication. This makes precise diagnosis even more important. INER is a national referral site and educational hospital, providing clinical services for the most frequent pulmonary diseases such as lung cancer, tuberculosis, interstitial diseases, etc., and these services are provided by experienced, certified pulmonologists and training pulmonologists. Services are intended to admit patients for each according to their disease; however, it is not possible always, so any service may conduct a diagnostic study for the patient. Therefore, the warrant for this study is that, although IPF diagnosis is made in the institute by pulmonologists, there is heterogeneity for accepting the use of diagnostic criteria in the different clinical services.