Sjogren’s Burden Determined by Organ Involvement, Fatigue, Pain, Study Suggests

Primary Sjögren’s syndrome (pSS) syndrome can be classified based on the extent of organ involvement, fatigue, and pain, with symptoms varying substantially from patient to patient, a new study reports.

The study, “Burden of illness among subgroups of patients with primary Sjögren’s syndrome and systemic involvement,” was published in Rheumatology. It was funded by GlaxoSmithKline.

pSS is predominantly characterized by dryness in the eyes and mouth due to reduced functioning of the salivary and tear glands. In some individuals, the disease also affects other organs, including the muscles, skin, and respiratory system. On rare occasions, it can cause life-threatening damage to the kidneys or nervous system.

Many people with Sjögren’s also experience fatigue and/or pain — though notably, prior studies have shown little association between patient-reported symptoms and objectively measured disease activity.

Because of person-to-person variation in how pSS manifests, more precise methods are needed to categorize the extent of disease burden in patients. Such classifications are important to help clinicians make accurate prognoses. They are also important for designing clinical trials and coming up with targeted treatment strategies.

In the new study, researchers from GlaxoSmithKline and Adelphi Real World set out to better understand how rheumatologists classify their pSS patients with systemic organ involvement in day-to-day practice. To this end, they conducted surveys of rheumatologists who care for people with the condition in France, Italy, Spain, Germany, and the U.S.

The physicians completed a general survey and patient record forms (PRFs) that captured symptoms, medications, demographics, and disease history for their next six eligible patients with pSS. These patients were given the opportunity to complete a patient self-completion (PSC) questionnaire, providing insight on disease, symptom severity, impact on health and quality of life, medication use, and treatment satisfaction.

In total, 316 physician surveys and 1,879 PRFs were completed. Of the PRFs, the optional PSC was completed by 888 patients. Most patients were female (89%) and white (89%); the overall average age was 53.2 years.

Based on the data, the researchers performed clustering analyses, which involve looking for groups, or “clusters,” of patients with similar characteristics. Their analysis yielded five distinct clusters.

One cluster, termed the “low-burden” cluster, included 324 (17%) patients who had little organ involvement, mental fatigue, or pain, but had higher levels of physical fatigue.

The second cluster (“low burden, articular”) included 384 (20%) patients who had articular involvement (joint problems). These patients reported some physical fatigue and pain, but little mental fatigue. Of note, patients in this cluster had the shortest average time since diagnosis (3.8 years).

The third cluster (“moderate burden, articular”) included 401 (21%) patients with articular involvement without much other organ involvement. It was similar to the second cluster, but included those with higher amounts of pain and fatigue.

The fourth cluster included 67 (4%) patients with a high degree of organ involvement across multiple organ systems. Patients in this cluster, dubbed “high burden, multi-organ,” experienced a moderate frequency of mental fatigue and very high frequencies of physical fatigue and pain. On average, patients in this cluster had been diagnosed the longest.

The final cluster included 703 (37%) patients with some organ involvement across systems. These patients experienced infrequent mental fatigue, a high frequency of physical fatigue, and the highest frequency of pain.

“In general, the cluster analysis highlighted the importance of considering both systemic and symptomatic manifestations of pSS when classifying patients and deciding upon appropriate management strategies,” the researchers wrote.

“Furthermore, there was a clearer separation between the clusters, which is likely a reflection of differences in the impact of the disease on [health-related quality of life], thus better reflecting treatment needs,” they added.

Of note, the “low-burden” cluster contained the highest proportion of patients who were satisfied with their treatment (82%), and the lowest proportion who were dissatisfied (8%).

Conversely, the “high-burden, multi-organ” cluster contained the fewest patients who were satisfied (47%) and the most who were dissatisfied (16%) — even though this cluster had the highest proportion of patients treated with corticosteroids (78%), biologics (43%), and conventional disease-modifying antirheumatic drugs (51%). Physician-reported treatment satisfaction followed similar trends.

“This study confirms that pSS disease burden is determined by fatigue and pain levels as well as organ involvement,” the researchers concluded. “Cluster analysis highlights the heterogeneous presentation of patients with pSS while identifying subsets of patients who may benefit from different treatment strategies.”