More than 10% of patients diagnosed with primary Sjögren’s syndrome at a French referral center reported little to no dryness in the mouth or eyes, and these individuals differed from the more typical Sjögren’s patients in other ways, too.
The “low dryness” patients were markedly younger and, oddly — given that oral and ocular dryness is the canonical symptom in Sjögren’s syndrome — were diagnosed more quickly, according to Raphaele Seror, MD, PhD, of Hôpital Bicêtre in Le Kremlin-Bicêtre in France, and colleagues. The researchers said theirs is the first study to focus on Sjögren’s patients without substantial dryness.
With 509 patients with Sjögren’s seen at the institution’s immunology and autoimmune diseases clinic, 53 had little to no subjective evidence of dryness, the group reported in RMD Open. Mean age for these patients was 51 at diagnosis, compared with 58 among the other 456. A similar difference in average age was seen in objective measures of oral or ocular dryness.
Moreover, the median time from symptom onset to diagnosis was shorter by 2 years in the subjective low-dryness group (2 vs 4 years, P=0.0056). Patients without notable dryness on objective testing were also diagnosed more quickly, but the difference (median 3 vs 4 years) wasn’t statistically significant.
“[P]hysicians should be aware that the absence of dryness should not rule out the diagnosis of [Sjögren’s syndrome], especially in young patients,” Seror and colleagues urged.
Nonglandular symptoms, while not universal, are common in Sjögren’s, “and can affect almost any organ,” the group noted; B-cell lymphoma is “the most feared.” Under classification criteria last updated in 2016, Sjögren’s can be diagnosed on the basis of serum markers (anti-nuclear antibodies) or sialadenitis without dryness necessarily present in the mouth or eyes.
Recognizing that patients without dryness were not rare, Seror’s group wanted to examine them more closely. The researchers pulled records for all Sjögren’s patients seen at their center from 1999 to 2020.
“High” subjective dryness in the mouth or eyes was defined as a score greater than 30 as gauged by patients on a 100-point scale. “High” subjective dryness was set as both of the following: a Schirmer’s test result of 5 mm/5 min or less and unstimulated whole salivary flow of 0.1 mL/min or less. Patients whose records lacked any of these tests were excluded. High dryness could also be established with abnormal ocular staining or Van Bijsterveld score.
Patients’ own assessments of dryness didn’t match the objective measures very well: of 113 with low or no objective dryness, just 17 met the definition of low/no subjective dryness. And, among the 53 with low/no subjective dryness, 33 “actually had high objective dryness,” the researchers indicated.
Nevertheless, both low/no dryness groups (i.e., objective or subjective) were significantly younger and were more likely to carry antinuclear (anti-SSA/Ro) antibodies. Every one of the 17 who had low/no dryness both objectively and subjectively tested positive for these serum markers.
Reasons for the discrepancy between patients’ self-assessments and objective dryness measures are uncertain. “[O]ne of the hypotheses [relates to] the quite high frequency of corneal neuropathy that may alter corneal sensitivity and prevent patients from experiencing subjective symptoms,” the researchers wrote. Why low salivary flow often wasn’t noticed by patients, however, is even less clear.
Limitations to the study were its retrospective design and reliance on past records, as well as the relatively small number of patients with low/no dryness.
The study had no specific external funding. Authors declared they had no relevant financial interests.
Source Reference: Kachaner A, et al “Comparison between primary Sjögren’s disease patients with high or low level of dryness” RMD Open 2023; DOI: 10.1136/rmdopen-2023-003291.