Home Spirometry: A Breakthrough Tool for Early Detection of SSc-ILD Decline

TOPLINE:

Home spirometry can help detect early lung function decline in patients with systemic sclerosis-associated interstitial lung disease (SSc-ILD). It has a good correlation with hospital tests, showing 60% sensitivity and 87% specificity for identifying progressive ILD.

METHODOLOGY:

• Researchers carried out a prospective, observational study to test home spirometry’s validity in patients with SSc-ILD.
• The study included 43 patients, 18 years or older, from two referral centers in the Netherlands. These patients received immunosuppressive treatment for up to 8 weeks before the baseline measurement.
• Participants took weekly home spirometry measurements using a handheld device for 1 year; 35 completed 6 months and 31 completed 12 months of follow-up.
• Hospital pulmonary function tests were conducted at baseline and during semiannual visits.
• The main outcome measured the agreement between home and hospital results in detecting a decline in forced vital capacity (FVC) of 5% or more. The study also assessed the sensitivity and specificity of home spirometry against hospital tests.

TAKEAWAY:

• Home spirometry showed fair agreement with hospital tests (κ, 0.40; 95% CI, 0.01-0.79).
• It had a sensitivity of 60% and a specificity of 87% for detecting a decline in FVC of 5% or more.
• The intraclass correlation coefficient for FVC measurements was 0.85 at baseline, 0.84 at 6 months, and 0.72 at 12 months.
• However, the long-term agreement between home and hospital measurements was lower, with a correlation coefficient of 0.55.

IN PRACTICE:

Experts found that home spirometry is feasible and moderately accurate for SSc-ILD patients. However, its low sensitivity in detecting FVC decline is a concern. The study suggests that home spirometry should be part of regular healthcare but should not replace standard monitoring.

SOURCE:

The study, led by Dr. Arthiha Velauthapillai from Radboud University Medical Center, was published in The Lancet Rheumatology on November 8, 2024.

LIMITATIONS:

The study may have been underpowered due to an unexpected lower prevalence of progressive ILD and a higher dropout rate. It involved only Dutch patients, which may limit the applicability of the findings in other regions with different internet access or literacy levels.

DISCLOSURES:

The study received partial funding from Galapagos and Boehringer Ingelheim. Some authors also received financial support from these and other pharmaceutical companies.