Concordance between different tools monitoring progression in interstitial lung diseases at 6 months-A prospective...

Interstitial lung disease (ILD) encompasses a wide variety of disorders with variable progression patterns. Monitoring typically involves assessing dyspnoea scores, spirometry parameters, 6-minute walk test (6MWT) parameters, and high-resolution CT (HRCT) scans. The agreement between the relative changes in these parameters over time is not known. To evaluate the concordance between changes in clinical, functional, physiological, and radiological parameters over 6 months in a diverse ILD cohort.

Prospective observational study conducted from 01 July 2022 to 31 January 2024 at a tertiary care teaching hospital.

Ninety-nine ILD patients underwent baseline and 6-month assessments of dyspnoea (mMRC), forced vital capacity (FVC), six-minute walk distance (6MWD), distance-saturation product (DSP), and HRCT. Patients were categorised as having lung-restricted or systemic disease-associated ILD. Changes were classified using established minimal clinically important differences. Concordance was analysed using weighted kappa; correlations were evaluated with Spearman's test.

Of 99 patients, 67.7% had ILD secondary to a systemic condition. Correlations between FVC, DSP, and 6MWD were moderate to strong both at baseline and at 6 months. Concordance among changes in clinical scores, FVC, 6MWD, and HRCT at the 6-month follow-up was low, with weighted-kappa values ranging from 0.023 to 0.158 for the overall study group. The strongest agreement was observed between clinical scores and FVC. The concordance was similarly poor in both subgroups.

Despite moderate baseline correlations, changes in different ILD monitoring parameters showed poor agreement, underscoring the multidimensional nature of disease progression. Comprehensive, multimodal follow-up remains essential, and multicentre validation is warranted.