The severity of Sjögren’s syndrome and its organ involvement has direct links to clinical characteristics that include age, gender, ethnicity, and geographical location, according to new research findings from a large, worldwide database of primary Sjögren’s syndrome patients.
Risk factors for more severe disease included male sex, earlier age at diagnosis, black/African-American (BAA) ethnicity, and living in more southerly countries, including below the equator. The authors hailed these factors as potentially helping to predict the presence of systemic disease in newly-diagnosed patients, as well as helping to determine the optimum follow-up strategy.
But not everyone agrees. In interviews, other experts suggested that the data were interesting and valuable, but were not ready to make reliable clinical predictions. “The predictive value of these data are limited when it comes to an individual patient sitting in front of you in the office,” said Tomas Mustelin, MD, professor of medicine at the University of Washington, Seattle.
“It would be an important clinical thing if you can figure out who’s at risk for systemic complications and who isn’t. This is a nice step in that direction,” said Hal Scofield, MD, professor of medicine and pathology at the University of Oklahoma, Oklahoma City, agreeing that the data were too preliminary to be broadly useful because there is too much overlap between different patient groups.
If there is one clinical message, it is that physicians should be looking beyond dry eyes and dry mouth in newly diagnosed Sjögren’s syndrome, according to Sarah Chung, MD, who is an acting instructor of rheumatology at the University of Washington. “It’s a reminder to investigate these extra-glandular manifestations, and a reminder that it is a heterogeneous presentation, so we have to keep an open mind and investigate thoroughly,” she said.
In the research published online in Rheumatology, first author Pilar Brito-Zerón, MD, PhD, of the University of Barcelona Hospital Clínic, and colleagues in the Sjögren Big Data Consortium used European League Against Rheumatism Sjögren’s syndrome disease activity index (ESSDAI) scores to examine phenotype and patient characteristics among 10,007 subjects drawn from the international consortium.
Dr. Pilar Brito-Zerón
Overall, 93.5% of subjects were women, and the mean age at diagnosis was 53 (standard deviation [SD], 14.1 years). The mean total ESSDAI score was 6.1 (SD, 7.5).
Men had higher mean ESSDAI (8.1 vs. 6.0; P less than .001) and clinical ESSDAI (8.4 vs. 6.1; P less than .001) scores and were more likely to have a high disease activity state (22.5% vs. 11.7%; P less than .001). Domains that scored higher in men included lymphadenopathy (P less than .001), glandular (P less than .001), pulmonary (P = .001), peripheral nervous system (PNS) (P less than .001), and CNS (P less than .001).
The highest global ESSDAI scores were reported in patients younger than 35, but organ dominance differed by age group: The constitutional, lymphadenopathy, glandular, cutaneous, renal, hematologic, and biologic domains were highest in this age group, but pulmonary and peripheral nervous system were highest in patients over 65.
By ethnicity, the highest ESSDAI scores occurred in black/African-American patients (6.7), followed by white (6.5), Asian (5.4), and Hispanic (4.8; P less than .001). The organ-specific domains also tracked by ethnicity, with BAA patients experiencing the highest frequencies of activity in the lymphadenopathy, articular, neurologic, and biologic domains. White patients were more often affected in the glandular, cutaneous, and muscular domains, whereas Asians most often experienced the pulmonary, renal, and hematologic domains, and Hispanics the constitutional domain.
The survey included Europe, America, and Asia, and global ESSDAI scores were higher in the southern countries of Asia and Europe, and higher in countries below the equator in the Americas. The organ-by-organ activity scores had a differentiated pattern between northern and southern locales. Worldwide, the gradient of patients with moderate systemic activity (global ESSDAI score of 5 or higher) at diagnosis followed a north-south gradient.
The study had no specific funding, and the authors have no relevant financial disclosures. Dr. Mustelin, Dr. Scofield, and Dr. Chung have no relevant financial disclosures.
SOURCE: Brito-Zerón P et al. Rheumatology. 2019 Dec 24. doi: 10.1093/rheumatology/kez578.