Psychometric properties of health-related quality of life assessment instruments in idiopathic pulmonary fibrosis: a systematic review applying COSMIN methodology

Abstract Background Idiopathic pulmonary fibrosis (IPF) is associated with heavy symptom burden, limited treatment options, poor prognosis, and significant economic burden, and severely impairs health-related quality of life (HRQoL). Optimizing HRQoL has become an important clinical goal in IPF management. Accurately assessing HRQoL is crucial for optimizing clinical practice and providing a key outcome measure data for clinical research. Although multiple HRQoL assessment instruments exist for IPF, the absence of a universally accepted gold standard, combined with insufficient systematic synthesis and standardized evaluation of their psychometric properties, hinders evidence-based instrument selection. This systematic review aims to provide clinicians and researchers with evidence-based guidance for selecting high-quality HRQoL assessment instruments for IPF by comprehensively evaluating existing instruments’ methodological quality and psychometric properties. Methods We conducted systematic searching through PubMed, Cochrane Library, Embase, and Web of Science from inception to June 26, 2025, for studies evaluating psychometric properties of HRQoL instruments in IPF. Two reviewers independently took charge of record screening, data extraction and quality assessment using the COnsensus-based Standards for the selection of health Measurement INstruments (COSMIN) methodology. Recommendations were formulated by integrating assessments with the evidence grading system. The protocol was registered with PROSPERO: CRD420251081250. Results Twenty-one studies covering fourteen HRQoL assessment scales for IPF were included. These scales comprised five generic instruments (e.g., St George’s Respiratory Questionnaire, EuroQol 5-dimension 5-level) and nine disease-specific tools (e.g., St George’s Respiratory Questionnaire-IPF-specific version (SGRQ-I), King’s Brief Interstitial Lung Disease questionnaire (K-BILD), Living with IPF questionnaire). Among the scales, the SGRQ-I and K-BILD were the most studied, with five studies each, and also had the most assessment dimensions of psychometric properties, covering seven properties each. A majority of scales lacked comprehensive validation of content and cross-cultural validity, and none reported measurement error test results. All fourteen scales were ultimately rated as Grade B recommendation. Conclusion Currently, no HRQoL assessment instruments can be unrestrictedly recommended for use in IPF based on the evaluation of their quality. We recommend that future studies draw on the COSMIN guidelines to refine the validation of psychometric properties for existing instruments, or to develop novel high-quality assessment instruments, facilitating accurate evaluation of HRQoL in IPF.