Study Targets Activity, Oxygen Issues in Advanced Sarcoidosis Patients

Patients with advanced sarcoidosis have limited daily life physical activity, mostly because their lungs’ maximal oxygen uptake is reduced, a study shows.

The findings of the study, “Daily life physical activity in patients with chronic stage IV sarcoidosis: A multicenter cohort study,” were published in the journal Health Science Reports.

Sarcoidosis is a rare chronic inflammatory disease of unknown origin that mainly affects the lungs. The disease has several degrees of severity, with stage 4 corresponding to the highest degree of disease severity in which patients develop chronic lung fibrosis (tissue scarring) and experience permanent lung damage.

“Patients with chronic respiratory diseases often display disabling dyspnea [shortness of breath] associated with a progressive reduction in daily life physical activity (DL_PA), as has previously been demonstrated in patients with interstitial lung diseases, including idiopathic pulmonary fibrosis,” researchers wrote.

“Reduced physical activity is an important clinical parameter related to increased morbidity, mortality, and hospitalizations in many chronic diseases,” they added.

However, very few studies assessed DL_PA in advanced pulmonary sarcoidosis patients who had already developed chronic lung fibrotic lesions.

In this study, a French scientists set out to assess DL_PA in a group of patients with stage 4 sarcoidosis, compared to healthy individuals used as controls. A secondary goal of the study was to determine factors that could be associated with DL_PA in patients with sarcoidosis.

The study analyzed 53 patients with chronic sarcoidosis, including 29 patients who had participated in a previous trial (NCT02044939) and 24 patients who were referred by their pulmonologists. In addition, 28 healthy controls also were analyzed.”

DL_PA was assessed through the number of steps walked per day (SPD) and total daily energy expenditure (TEE), that were measured for five consecutive days using a physical activity monitor. Lung function, including maximal oxygen consumption (VO₂max), exercise capacity (6-minute walk test [6MWT]), and patients’ quality of life (self-reported by the Visual Simplified Respiratory Questionnaire score), also were assessed throughout the study.

After normalization for age, sex, and body mass index (BMI), results showed that patients with chronic sarcoidosis had significantly lower SPD compared to controls (6,395 vs 11,817). Conversely, TEE was identical in both groups (median of 2,369 vs 2,387 kilocalories/day).

Correlation analysis demonstrated that SPD was positively correlated with the distance individuals were able to cover during the 6MWT, VO₂max, and patients’ quality of life. In contrast, SPD was negatively correlated with patients’ shortness of breath (measured by the modified Medical Research Council questionnaire score).

In addition, further analysis revealed that TEE was correlated with BMI, forced expiratory volume in one second (FEV1), forced vital capacity (FVC), and total lung capacity (TLC).

Collectively, these findings demonstrated that “DL_PA is reduced in patients with chronic stage 4 sarcoidosis compared with control subjects” and that is “mainly because of compromised VO₂max,” researchers said.

“However, pulmonary function tests were insufficient to evaluate DL_PA in our study, and other parameters must be evaluated to understand all determinants of DL_PA in patients with chronic sarcoidosis,” the team wrote.

Additional studies should assess how DL_PA changes in this population during and after pulmonary rehabilitation, the team suggested.