Sjögren’s syndrome (SS) is one potential cause of dry mouth.  It is thought to affect 0.5-1% of the population and is more common in females (M/F ratio 1:9).  SS is an autoimmune disease characterised by chronic T- and B-cell infiltration of the salivary glands or lachrymal glands that results in gland dysfunction.   SS has a variable clinical and laboratory presentation so can be difficult to diagnose. Minor salivary gland biopsy (MSGB) is used in diagnosing SS and this review aimed to assess the diagnostic value of MSGB.

The Pubmed and Embase databases were searched together with reference lists of selected articles and abstract databases from recent (2010-11) American College of Rheumatology (ACR) and European League Against Rheumatism (EULAR) meetings. Publications in English, French, or Spanish were included. Study quality was not assessed with validated tools.

• 9 studies were included 5 were retrospective.
• In 8 studies, the population was composed of patients presenting with suspected primary or secondary SS. 1 study was done in a cohort of patients with sicca syndrome.
• Sensitivity and specificity were available for all 9 studies and Positive (PPV) and negative predictive values (NPV) were estimated:-
  • Sensitivity   63.5% to 93.7%
  • Specificity   61.2% to 100%
  • PPV              74.2% to 100%
  • NPV             39.1% to 96.1%

The authors concluded

this systematic review of the literature shows a paucity of knowledge about, and probable limitations of, MSGB as a diagnostic test for SS. However, the specificity is elevated and sensitivity may vary due to inclusion criteria. These results strongly support the need for larger studies designed to redefine the role for MSGB in future diagnostic criteria.

Comment

Assessing the diagnostic accuracy of test for SS is challenging for as the authors note there is no single standard reference test to compare tests against.  As with other areas standards for reporting diagnostic test accuracy do now exist (STARD – Statement) and the Cochrane Collaboration is developing a handbook for conducting reviews of diagnostic test accuracy.  If researchers and journal editors being to apply these standards then clinicians will be better informed about the usefulness of available tests.

Links

Guellec D, Cornec D, Jousse-Joulin S, Marhadour T, Marcorelles P, Pers JO, Saraux A, Devauchelle-Pensec V. Diagnostic value of labial minor salivary gland biopsy for Sjögren’s syndrome: A systematic review. Autoimmun Rev. 2012 Aug 7. [Epub ahead of print] PubMed PMID: 22889617.

Cochrane Diagnostic Test Accuracy Working Group

STAndards for the Reporting of Diagnostic accuracy studies