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Researchers reported that the Clinical Frailty Scale was useful in stratifying patients with fibrotic interstitial lung disease at risk for early mortality.

The Clinical Frailty Scale (CFS) accurately predicted pulmonary and physical function decline among people with fibrotic interstitial lung disease (ILD), researchers recently reported in CHEST.

“The [CFS] is a simple tool designed to summarize overall fitness and frailty in a person,” wrote Sabina A. Guler, MD, and colleagues. “The goal of this study was to establish if the simple and practical CFS might be a valid tool to improve risk stratification in patients with fibrotic ILD. Specifically, we aimed to determine the relationship between frailty assessed by the CFS and transplant-free survival in the most common fibrotic ILDs, to determine the incremental contribution of the CFS to mortality risk prediction, and to explore ILD progression by frailty status.”

In an observational cohort study, Dr. Guler and colleagues calculated CFS scores using data from patients with fibrotic ILD from the Canadian Registry for Pulmonary Fibrosis. The researchers calculated patients’ scores using information recorded at initial visits to ILD clinics and then stratified them by score.

Those considered “fit” had a CFS score of 1-3, whereas those with a score of 4 were considered “vulnerable,” and those with scores ranging from 5-9 were considered “frail.” They used logistic regression models and Cox proportional hazards to estimate patients’ time to lung transplant or death and established prognostic performance with a derivation and validation cohort.

A total of 1,587 patients in the study had fibrotic ILD. Slightly more than half (54%; n=858) were fit, whereas 25% (n=400) were vulnerable and 21% (n=329) were frail.

Frailty was a significant risk factor for early mortality (Table). The researchers reported that this association held for individual diagnoses (idiopathic pulmonary fibrosis, connective tissue disease-associated ILD, fibrotic hypersensitivity pneumonitis, and unclassifiable ILD) and the overall cohort, and after researchers adjusted for confounding factors.

In addition, over a median follow-up of 1.3 years (IQR, 0.4-2.6), mean annual FVC % predicted declined by:

• −1.55 (95% CI, −2.04 to −1.15) in the fit subgroup;
• −1.92 (95% CI, −3.10 to −0.94) in the vulnerable subgroup; and
• −2.32 (95% CI, −3.39 to −1.17) in the frail subgroup.

Similarly, mean annual diffusing capacity of the lung for carbon monoxide (DLCO) % predicted showed respective declines of:

• −1.96 (95% CI, −2.44 to −1.57);
• −2.20 (95% CI, −3.61 to −1.11); and
• −2.56 (95% CI, −4.02 to −1.24).

Lastly, mean annual 6-minute walking tests % predicted declined in each respective subgroup by:

• −2.23 (95% CI, −2.89 to −1.60);
• −4.23 (95% CI, −6.63 to −2.46); and
• −3.40 (95% CI, −5.47 to −1.48).

The findings also showed that incorporating frailty boosted the prognostic performance of other established risk models. Adding frailty to age, sex, BMI, and history of smoking increased the C-index from 69.1% to 74.4%, while adding it to the ILD-Gender-Age-Physiology Index increased the C-Index from 72.9% to 76.2%.

The study was limited by missing data, which the researchers acknowledge as a common shortcoming of observational cohort studies. Missing data in this study included missing FVC information in 8.5% of patients, no DLCO tests in 14%, and 6-minute walking tests missing for about 43% of patients. The study was also limited to patients from a single country, though researchers described the population as robust. Finally, the researchers noted that more elaborate tests may provide more granular insight.

“We established the potential role of the CFS for risk stratification in patients with fibrotic ILD,” Dr. Guler and colleagues concluded. “The CFS might support communication among ILD specialists, patients, and caregivers, and serve as a tool for individual allocation of disease-modifying and supportive treatments.”