Health-related quality of life measured with K-BILD is associated with survival in patients with idiopathic pulmonary fibrosis

Background: Health-related quality of life (HRQoL) assessments and estimates of prognosis are needed for comprehensive care and planning of subsequent treatment in patients with idiopathic pulmonary fibrosis (IPF). We investigated HRQoL and its association with survival using a disease-specific tool in patients with IPF.

Methods: The patients were recruited from the real-life FinnishIPF study in 2015. HRQoL was assessed with the King's Brief Interstitial Lung Disease (K-BILD) questionnaire every six months for 2.5 years. Dyspnoea was assessed with the modified Medical Research Council (mMRC) dyspnoea scale. Survival was registered until 31 December 2022. Patient survival according to the K-BILD total score was evaluated using the Kaplan‒Meier method. The Friedman test was used to compare the K-BILD total scores longitudinally, and the Mann‒Whitney U test was used to compare the mMRC groups. P values < 0.05 were considered statistically significant.

Results: The median K-BILD total score (n = 245) was 51.6. At baseline, patients in the highest HRQoL quartile (K-BILD scores 58.9-100) had a longer median survival time (5.3 years) than did those with scores of 51.7-58.8 (3.1 years), 45.7-51.6 (2.3 years), and 0.0-45.6 (1.8 years). A decrease in the K-BILD total score of ≥ 5 units in the preceding 12 or 24 months showed a trend towards poorer survival, although statistical significance was not reached. Ninety-four patients survived more than 2.5 years and had available K-BILD data at all time points. The K-BILD total score remained higher in patients with a baseline mMRC of 0-1 than in those with a mMRC of 2-4, and the total score decreased only modestly in both groups (median of 3.3 and 4.8 units in patients with mMRC scores of 0-1 and 2-4, respectively).

Conclusions: In IPF, a reduced HRQoL is associated with impaired survival. A K-BILD total score less than approximately 50 units is associated with a median survival of approximately two years. In addition to assessing the treatment needs of patients with IPF using K-BILD, a decreased score may be useful for facilitating advance care planning and transplantation assessment.