Can unstimulated whole salivary flow objectively classify salivary gland secretory function in Sjögren’s syndrome?
摘要
The aim of this study is to investigate whether the testing time for unstimulated whole salivary flow (UWSF) can be shortened to 5 min in patients with suspected Sjögren’s syndrome (SjS); and which SjS patients can use UWSF to evaluate salivary gland (SG) secretory function.
MethodA diagnostic cohort comprising suspected SjS patients was conducted to investigate the correlation between UWSF measurements taken at 10 min (UWSF_10 min) and those taken at 5 min (UWSF_5 min). A group of SjS patients was enrolled for a comparison between UWSF and stimulated whole salivary flow (SWSF).
ResultsIn 734 suspected SjS patients, there was a remarkably high concordance between UWSF_10 min and UWSF_5 min (ICC 0.970, P < 0.001; r 0.973, P < 0.001). Reducing the testing time for UWSF to 5 min resulted in a high PPV of 83.8% and an exceptionally high NPV of 98.7%. In 408 SjS patients, the cut-off values of UWSF_10 min were investigated to classify SG secretory function. Using a threshold of > 0.2 mL/min (36.8%, 150/408) instead of SWSF > 0.7 mL/min (indicating mild secretory hypofunction), the specificity and PPV were found to be 94.2% and 94.0%, respectively; and using a threshold of < 0.05 mL/min (16.9%, 69/408) instead of SWSF ≤ 0.7 mL/min (indicating moderate to severe secretory hypofunction), the specificity was remarkably high at 97.6%, accompanied by a high PPV of 91.3%.
ConclusionsThis study supports the possibility of reducing UWSF testing time to 5 min; and the SWSF test may be skipped for SjS patients with USWF > 0.2 mL/min, indicating mild secretory hypofunction, or < 0.05 mL/min, indicating moderate to severe secretory hypofunction.