Severe fatigue affects more than 60% of pulmonary sarcoidosis patients and is associated with worse shortness of breath, daytime sleepiness, anxiety and depression, catastrophizing, functional impairments, and quality of life, according to a Dutch study.
The research also showed similar findings for people with idiopathic pulmonary fibrosis (IPF), another interstitial lung disease (ILD), highlighting the high frequency of severe fatigue among ILD patients and the importance of monitoring and managing this symptom in these patients.
The study, “Severe Fatigue is Highly Prevalent in Patients with IPF or Sarcoidosis,” was published in the Journal of Clinical Medicine.
Sarcoidosis leads to the formation of small abnormal lumps or nodules — called granulomas — in several organs of the body, but most often in the lungs (pulmonary sarcoidosis).
The disease is part of a larger group of more than 200 chronic lung disorders — known collectively as ILDs — that cause inflammation and scarring in the tissue in and around the lung air sacs, impairing the lungs’ ability to transfer oxygen to the bloodstream.
IPF, the most common ILD, is a condition in which the lungs become irreversibly scarred and cease to work properly.
Previous studies have shown that fatigue — a feeling of tiredness or exhaustion — is a common symptom among people with sarcoidosis and IPF. Fatigue, which can negatively affect a patient’s quality of life, seems to be associated with health status and greater functional difficulties, regardless of the degree of lung function impairment.
Despite fatigue’s apparent relevance in ILD patients, the frequency of severe fatigue and its associated factors remain unclear in this patient population.
A team of researchers in the Netherlands now evaluated the occurrence of severe fatigue in ILD patients and its potential association with other clinical factors.
Participants’ median age was 66 years and more than half were men (62.4%), had at least another clinical condition or comorbidity (62.4%), had a history of smoking (58.6%), and had completed at least high school (63.5%).
Notably, compared with IPF patients, the sarcoidosis group had fewer men (48.3% vs. 76.3% in the IPF group), was younger (53.5 vs. 73 years), and were more educated (79.3% vs. 47.4%), had fewer current or past smokers (38.6% vs. 78%), and slightly better lung function.
Fatigue was measured with the Checklist Individual Strength-Fatigue (CIS-Fat), a validated questionnaire in which a score of 26 or less is considered normal fatigue, a score between 27 and 35 represents mild fatigue, and a score higher than 35 indicates severe fatigue.
Other validated questionnaires and scales were used to assess factors such as shortness of breath, daytime sleepiness, anxiety, depression, fatigue-related catastrophizing (to think of a situation as worse than it actually is), functional impairment, overall health status, and quality of life.
Results showed that the mean fatigue score of ILD patients was 37 points (classified as severe), with sarcoidosis patients having a significantly higher mean score (40 points) than the IPF group (34.1 points, considered mild fatigue).
Also, 69% of participants within the sarcoidosis group had severe fatigue, compared to 47.5% in the IPF group.
These findings highlighted the high prevalence of severe fatigue among ILD patients, particularly those with pulmonary sarcoidosis. This was surprising, considering that the sarcoidosis group seemed to have characteristics associated with better overall and lung health and less functional impairment than the IPF group, the researchers noted.
Sarcoidosis patients with severe fatigue were found to be significantly less educated, had more regular visits to a psychologist, and smoked more than those with normal or mild fatigue.
Moreover, severe fatigue in the sarcoidosis group was found to be significantly associated with more severe shortness of breath, daytime sleepiness, anxiety, depression, catastrophizing, functional activity impairments, and a poorer quality of life.
The team emphasized that while catastrophizing can influence the experience of fatigue and was reported previously to be a good predictor of fatigue severity, this was the first study evaluating an association between catastrophizing and fatigue in ILD patients.
They also pointed out that excessive daytime sleepiness or poor sleep quality may not be “the main driver” of severe fatigue in people with ILD.
“To conclude, fatigue is an important symptom in patients with ILD,” researchers wrote.
“In clinical management of patients with ILD, it is recommended to assess fatigue, catastrophizing thoughts, and causal attributions of fatigue, because these elements together with dyspnea [shortness of breath] are related to the functional impairments in activities of the patients,” they suggested.
The team highlighted that future studies following patients over time and including psychological and physical functional aspects are needed to better understand severe fatigue in ILD patients and its long-term impact on patients’ quality of life.