Divergent perspectives: exploring the relationships between St. George's Respiratory Questionnaire and outcome measures in systemic sclerosis-associated interstitial lung disease

Introduction/objectives: Controversy exists regarding the concordance of patient-reported outcome measures (PROMs) with other assessment parameters in systemic sclerosis-associated interstitial lung disease (SSc-ILD). This study aims to explore the association between the St. George's Respiratory Questionnaire (SGRQ) and various outcome measures in patients with SSc-ILD within a real-world cross-sectional setting.

Method: Patients with SSc-ILD were consecutively recruited from our SSc cohort. Simultaneous administration of SGRQ, scleroderma Health Assessment Questionnaire (sHAQ), respiratory visual analog scale (R-VAS), pulmonary function tests (PFTs), and the 6-min walking test (6-MWT) was conducted. The total extent of lung fibrosis was quantified using high-resolution computed tomography (HRCT) images. Relationships between SGRQ and functional, radiographic, and other patient-reported outcome measures were analyzed.

Results: The total SGRQ score demonstrated correlations with forced vital capacity (FVC) and R-VAS (r = - 0.397, p = 0.016 and r = 0.418, p = 0.027, respectively). Symptom score correlated with ILD-extension (r = 0.430, p = 0.005); activity score correlated with FVC and R-VAS (r = - 0.502, p = 0.002 and r = 0.395, p = 0.038, respectively); impact score correlated with R-VAS (r = 0.386, p = 0.043). In patients with fibrosis extent exceeding 20%, total SGRQ score was associated with sHAQ and R-VAS (r = 0.398, p = 0.049; r = 0.524, p = 0.021, respectively), activity score with R-VAS (r = 0.478, p = 0.038), and impact score with 6-MWT-D and R-VAS (r = - 0.489, p = 0.034; r = 0.545, p = 0.016, respectively). The symptom score and activity score demonstrated optimal performance in identifying patients with interstitial lung disease (ILD) extent exceeding 20% and forced vital capacity (FVC) less than 70% (area under the curve [AUC] 0.799, p = 0.002, and AUC 0.792, p = 0.03, respectively).

Conclusions: Our study reveals varying degrees of correlation between SGRQ and distinct outcome measures. Given the incomplete alignment of SGRQ with other outcome measures, an integrative approach utilizing existing criteria as complementary tools is recommended. Key Points • Patient-reported outcome measures (PROMs) derive from patients' subjective evaluations of the impact of the disease on their daily activities, social interactions, and psychological well-being. • PROMs frequently serve as outcome measures in randomized controlled trials, yet conflicting findings have emerged in relation to primary outcomes. • This study aims to assess the appropriateness and interrelation of PROMs with both radiological and functional outcome measures, providing insight into the current state of our patients in a real-life context. The investigation delves into the compatibility of these measures with each other.