Original articleEvaluation of health-related quality-of-life and dyspnea scales in patients with idiopathic pulmonary fibrosis. Correlation with pulmonary function tests☆
Introduction
Idiopathic pulmonary fibrosis (IPF), also known as cryptogenic fibrosing alveolitis, is a severe, chronic, progressive interstitial lung disease (ILD) with significant morbidity and mortality [1]. According to the current definition, IPF is a distinctive type of chronic fibrosing interstitial pneumonia of unknown cause that is limited to the lungs and associated with a surgical lung biopsy showing a histological pattern of usual interstitial pneumonia [2]. The median survival for IPF is 3–5 years, with the majority of patients suffering from progressive respiratory failure with severe hypoxemia and shortness of breath [1]. Bjoraker et al. found a 2.8% survival rate after 5 years in patients with histologically confirmed IPF, even with treatment [3].
The different courses of the disease and differences in treatment response that have previously been observed appear to be due to the different histologic types. However, the current classification schema [2] allows for a better understanding of the entire group of ILD. The stage of disease at the time of diagnosis, subsequent disease activity, response to therapy and disease-associated complications all affect survival and morbidity. An objective response to corticosteroids is observed in only 20% of IPF patients without previous histologic confirmation [4], [5]. Today, it is believed that responders have a histologic type of disease that is not the usual interstitial pneumonia [2].
Current medications, corticosteroids and immunosuppressive agents in particular are associated with significant side effects [6], [7]. Moreover, as the disease progresses, patients become severely disabled and permanently dependent upon supplemental oxygen [2]. It is, therefore, obvious that IPF has a significant impact on a patient's functional health and well-being.
Health-related quality of life (HRQoL), along with measures of morbidity and mortality, can be used to make medical decisions, such as initiating, changing or terminating treatment. It is considered a very important parameter in the management of patients and it is evaluated in most clinical trials. HRQoL includes abilities, impairments, symptoms and psychosocial results that are due to a disease [8]. Health status questionnaires provide a method of quantifying the effect of disease on patients' functioning in chronic lung diseases such as asthma and COPD [9], [10]. HRQoL in diffuse interstitial lung diseases (ILD) was not studied until 1996. Since 1996, several groups throughout the world have started to study the impact of HRQoL on the most common chronic ILD using various generic and respiratory-specific health status and QoL instruments [12], [13], [14], [15]. Very little has been reported on the health status and QoL of IPF patients [11], [12], [15], [16], [17]. This is mainly attributed to the low incidence/prevalence of IPF. Investigators simply do not have access to a large enough population of IPF patients whose functional status and HRQoL they can study in a timely manner.
In a recent study, Chang et al. looked at two general questionnaires–the Short Form 36 (SF-36) and the Quality of Well-Being (QWB)–and two specific respiratory questionnaires–the St. George's Respiratory Questionnaire (SGRQ) and the Chronic Respiratory Questionnaire (CRQ)–in order to determine their sensitivity in assessing HRQoL in IPF [15]. They found that these pre-existing health status and QoL instruments could be applied to patients with such ILD as IPF, sarcoidosis, hypersensitivity pneumonitis and asbestosis [15]. However, for IPF, the greatest impact on HRQoL, as seen in everyday practice, appears to be caused by dyspnea. It is not yet known what the relationship is between IPF and the several dyspnea scales used in other chronic lung diseases [18], [19]. Therefore, the aim of this study was to investigate HRQoL and particularly to test whether existing instruments for obstructive airway disease could be applied to patients with IPF.
Section snippets
Subjects
Twenty-five consecutive outpatients with clinically and histologically consistent IPF were followed up at our hospital from January 1994 until July 1999. The diagnosis of IPF was based on consistent clinical features and radiographic findings, and was then confirmed by biopsy showing either common interstitial pneumonitis or non-specific interstitial pneumonitis consistent with IPF [2]. Initially, 32 patients with IPF were contacted. Seven were excluded for various reasons, mainly due to the
Clinical characteristics
The demographic and clinical characteristics of both the IPF population and the control group are listed in Table 1. None of the participating subjects had any significant medical history that could affect HRQoL. Patients had no co-morbidity (e.g., heart failure, cancer or diabetes mellitus).
Pulmonary function
Mean values (S.D.) of pulmonary function tests and arterial PaO2 data of IPF patients and control subjects are shown in Table 2. Nineteen patients had a decreased KCO and eight of them had developed
Discussion
The health status of patients with ILD has not been studied systemically despite the increasing number of publications on other respiratory diseases (e.g., asthma, COPD, cystic fibrosis, lung cancer) [8]. This may be attributed to (1) the variety of different entities included, (2) the rarity of each disease and the small number of patients seen, even in reference centers, or (3) the heterogeneity at initial staging and the course of the diseases, treated or not [11]. We started to systemically
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2017, Respiratory MedicineCitation Excerpt :Several authors have shown that increased severity of dyspnea correlates with worse HRQL among patients with ILD [5–7], including patients with connective tissue disease-associated ILD[15]. Impairments in pulmonary function are associated with dyspnea severity [11, 16], but it is well known that several other factors (e.g., limbic system activation[17]) contribute to the perception of dyspnea. For example, ILD patients with more severe dyspnea have higher rates of depression and a greater degree of functional impairment, which contribute to the sensation of breathlessness beyond their baseline pulmonary function[18].
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This work was presented in part at the annual congress of the American Thoracic Society, New Orleans, May 10–15, 1996, and at the annual congress of the European Respiratory Society, Stockholm, Sweden, September 7–11, 1996.