In people with Sjögren’s-associated ILD, PF is linked to poor survival

Researchers identified low albumin as potential risk factor

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by Andrea Lobo |

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People with Sjögren’s syndrome-associated interstitial lung disease (ILD) who develop pulmonary fibrosis (PF) have poorer survival than those without PF, a study in Taiwan finds.

Researchers found that continuously low albumin levels — a sign of inflammation — could act as a risk factor for developing PF. A smaller improvement in lung function parameters and radiological signs of lung tissue scarring, or fibrosis, also were observed among Sjögren’s patients with PF.

These findings suggest “close monitoring [of] inflammatory markers and [pulmonary function tests] could be helpful for the early detection of PF,” the researchers wrote in “Clinical outcomes and risk factors of progressive pulmonary fibrosis in primary Sjögren’s syndrome-associated interstitial lung disease,” which was published in BMC Pulmonary Medicine.

ILDs comprise a group of lung disorders marked by inflammation and tissue scarring, including PF. Certain autoimmune diseases, such as Sjögren’s syndrome, may also be associated with PF and other ILDs.

Although the risk factors for PF in other conditions have been characterized, they haven’t been with Sjögren’s syndrome, leading researchers to retrospectively analyze data from 153 people with Sjögren’s syndrome-associated ILD, who’d been followed for three years after being diagnosed. The data were collected from a medical database at Taiwan University Hospital between January 2015 and August 2021.

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Developing PF with primary Sjögren’s syndrome

Of the patients analyzed, 68 had primary Sjögren’s syndrome, a form that’s not associated with any other underlying health condition. Half developed PF, while the other half didn’t.

Both groups were similar in age, sex, lung function, and imaging findings. The inflammatory and autoimmune profile in the groups was also identical.

Most patients in both groups were receiving disease-modifying anti-rheumatic drugs and/or corticosteroids in the three months after their diagnosis.

At the third month of follow-up, PF patients had significantly lower albumin levels (3.85 vs. 4.2 g/dL) than those without PF, suggesting a higher degree of inflammation. Persistently low albumin was associated with developing PF, a subsequent statistical analysis confirmed. This indicates in these patients, a “persistent lower albumin level might be the risk factor of [PF],” the researchers said.

Pulmonary function tests were conducted when patients were included in the study (baseline) as well as one and two years later. After one and two years, PF participants saw a decline in their lung function compared with baseline, whereas lung function improved in those without PF.

After two years, PF patients saw a decline of 1.4% in forced vital capacity (FVC) and of 3.5% in diffusion capacity of carbon monoxide (DLCO). Patients without PF saw their FVC increase by 14.2% and their DLCO increase by 8.8%. A similar trend was seen at the one year. FVC measures the maximum amount of air a person can forcibly exhale after a deep breath. DLCO measures how well gases can be transferred from the lungs into the bloodstream.

A higher proportion of PF patients showed signs of honeycombing, a typical fibrotic tissue pattern, in lung imaging scans over those without PF (81% vs. 33%).

Patients had an overall survival rate of 91.2% after three years. This was significantly lower among those with PF than those without it (82.4% vs. 100%).

Six PF patients (four women, two men) died due to respiratory problems during the three-year follow-up. Four showed signs of lung fibrosis in imaging scans. No deaths were reported in the group who didn’t have PF.

Researchers identified low albumin levels as a potential risk factor for developing PF with primary Sjögren’s syndrome-associated ILD. These patients also showed poorer lung function and radiological features than those without PF.

More research “with larger sample size or prospective design” is needed to confirm the findings, the researchers said.

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