Psychometric properties and minimal important differences of SF-36 in Idiopathic Pulmonary Fibrosis

Abstract

Background Idiopathic pulmonary fibrosis (IPF) is a rare disease with a median survival of 3–5 years after diagnosis with limited treatment options. The aim of this study is to assess the psychometric characteristics of the Short Form 36 Health Status Questionnaire (SF-36) in IPF and to provide disease specific minimally important differences (MID). Methods Data source was the European IPF Registry (eurIPFreg). The psychometric properties of the SF-36 version 2 were evaluated based on objective clinical measures as well as subjective perception. We analysed acceptance, feasibility, discrimination ability, construct and criterion validity, responsiveness and test-retest-reliability. MIDs were estimated via distribution and anchor-based approaches. Results The study population included 258 individuals (73.3% male; mean age 67.3 years, SD 10.7). Of them 75.2% (194 individuals) had no missing item. The distribution of several items was skewed, although floor effect was acceptable. Physical component score (PCS) correlated significantly and moderately with several anchors, whereas the correlations of mental component score (MCS) and anchors were only small. The tests showed mainly significant lower HRQL in individuals with long-term oxygen therapy. Analyses in stable individuals did not show significant changes of HRQL except for one dimension and anchor. Individuals with relevant changes of the health status based on the anchors had significant changes in all SF-36 dimensions and summary scales except for the dimension PAIN. PCS and MCS had mean MIDs of five and six, respectively. Mean MIDs of the dimensions ranged from seven to 21. Conclusion It seems that the SF-36 is a valid instrument to measure HRQL in IPF and so can be used in RCTs or individual monitoring of disease. Nevertheless, the additional evaluation of longitudinal aspects and MIDs can be recommended to further analyse these factors. Our findings have a great potential impact on the evaluation of IPF patients. Trial registration The eurIPFreg and eurIPFbank are listed in https://clinicaltrials.gov ( NCT02951416 ). Electronic supplementary material The online version of this article (10.1186/s12931-019-1010-5) contains supplementary material, which is available to authorized users.

Clinical and Functional Characteristics of Patients with Unclassifiable Interstitial Lung Disease (uILD): Long-Term Follow-Up Data from European IPF Registry (eurIPFreg)

“…The aim of SF-36 is to characterize and understand the relationship between the selected baseline clinical covariates, the physical component score (PCS), and the mental component score (MCS) [25]. This questionnaire is a validated instrument for assessing HRQoL and has been applied to a variety of chronic medical conditions, including IPF [7]. The SF-36, as described in the name, is a 36-item patient-reported questionnaire that evaluates eight health domains: physical functioning (10 items), bodily pain (2 items), role limitations due to physical health problems (4 items), role limitations due to personal or emotional problems (4 items), emotional well-being (5 items), social functioning (2 items), energy/fatigue (4 items), and general health perceptions (5 items).…”

“…ILDs may occur due to a known cause such as drugs, connective tissue disease (CTD), hypersensitivity to inhaled organic antigens (hypersensitivity pneumonitis, HP), or sarcoidosis; whilst others, especially sporadic idiopathic interstitial pneumonias (IIPs), have no identifiable origin [4]. Of them, idiopathic pulmonary fibrosis (IPF) is associated with the highest burden and poor prognosis [5][6][7]. Apart from IPF, other IIPs include idiopathic non-specific interstitial pneumonia (NSIP), respiratory bronchiolitis-ILD (RB-ILD), desquamative interstitial pneumonia (DIP), cryptogenic organizing pneumonia (COP), acute interstitial pneumonia (AIP), and some other rare forms [8,9].…”

Disease Severity and Quality of Life in Patients With Idiopathic Pulmonary Fibrosis

“…In the IPF-PRO registry, the observed within-patient correlations for QOL metrics (Objective 2) showed that physical QOL domains were most strongly correlated with overall scores (eg, total SGRQ and SF-12 PCS), suggesting that QOL in IPF may be strongly affected by physical limitations, as has been reported. 29 Given the lack of consensus-based standards for characterization of disease severity in IPF, our study adds to the literature by describing within-patient concordance between severity classifications. We observed modest correlations between GAP and CPI (R w 0.60), indicating that each metric may offer independent information, an interesting finding given that similar clinical variables are used in their calculations.…”

What Patients With Idiopathic Pulmonary Fibrosis and Caregivers Want: Filling the Gaps With Patient Reported Outcomes and Experience Measures

“…9 Generic PROMs such as Euroqol-5D and short form-36 have been used in this condition. 32,33 Disease-specific PROMs, such as Saint George Respiratory Questionnaire (SGRQ) 34 and COPD assessment Test (CAT), 35 although not specific for idiopathic pulmonary fibrosis, have also been used. In addition, idiopathic pulmonary fibrosis-specific tools such as SGRQ-IPF, 36 the cross Atlantic tool to assess quality of life in IPF (ATAQ-IPFca) 3,7 and King's Brief Interstitial Lung Disease (K-BILD)…”

“…Such information needs to be delivered at the first visit and revisited throughout the course of the disease. 33 and symptoms (MYMOP) 57 Health care experience disconnected from patient reality and daily needs 54,79 Lack of: 1) MDT and PC approach; 2) prioritization of symptom/need assessment; 3) integrated advanced care planning; 4) communication and information skills…”