Lung function is associated with minimal EQ-5D changes over time in patients with systemic sclerosis.

Area of Science:

• Pulmonary Medicine
• Rheumatology
• Health Outcomes Research

Background:

• Systemic sclerosis (SSc) management often targets respiratory complications.
• The relationship between pulmonary function test (PFT) changes and health-related quality of life (HRQoL) in SSc is not well-defined.
• Assessing HRQoL longitudinally is crucial for understanding patient well-being in chronic diseases.

Purpose of the Study:

• To investigate the association between longitudinal changes in PFTs (Forced Vital Capacity % - FVC% and Diffusing Capacity of the Lungs for Carbon Monoxide % - DLCO%) and HRQoL in SSc patients.
• To determine how modifications in lung function influence patient-reported outcomes using the EQ-5D questionnaire.
• To quantify the impact of PFT variations on different domains of HRQoL.

Main Methods:

• Longitudinal study design including SSc patients with at least two assessments of FVC%, DLCO%, and EQ-5D.
• Generalized estimating equations were used to analyze the association between changes in PFTs and EQ-5D scores (utility and Visual Analogue Scale - VAS) over time.
• A cohort of 378 patients with 1619 measurements was analyzed.

Main Results:

• An improvement in FVC% was significantly associated with increases in both EQ-5D utility score (β=0.001, p=0.003) and VAS (β=0.188, p<0.001).
• An improvement in DLCO% was significantly associated with an increase in the EQ-5D utility score (β=0.001, p=0.038).
• The association between DLCO% improvement and VAS was not statistically significant (β=0.020, p=0.690).

Conclusions:

• Changes in PFTs have a statistically significant, albeit minor, impact on HRQoL in SSc patients as measured by the EQ-5D.
• In SSc-ILD patients, HRQoL perception is minimally influenced by pulmonary function changes.
• Generic HRQoL questionnaires may lack sensitivity to detect the impact of targeted therapies on specific SSc manifestations.