Developing the Hardtack Test to Screen and Monitor the Sjogren's Syndrome in Korea

Kim, Sung Soo; Song, Jung Soo; Park, Bo Hyoung; Lee, Yong Hwan; Bae, Sung Kwon; Park, Won

Abstract

OBJECTIVE
To investigate the usefulness of the Hardtack test to screen the Sjogren's syndrome compared with non-stimulated whole salivary flow (NSWSF) and Schirmer-1 test.
METHODS
Fifty patients with RA and other connective tissue disease who had complained sicca symptoms (7 males and 43 females) and twenty healthy participant, were undergone the Hardtack test, NSWSF, and Schirmer-1 test. The Hardtrack test were compared with NSWSF and Schirmer-1 test for the screening of Sjogren's syndrome. And the relationship between the tests were evaluated.
RESULTS
1) The time of dissolution of the hardtack was 88.7sec (Max: 136, Min: 44) in healthy group, and 321 sec (Ma: 900, Min: 92) in patient group (p<0.001). 2) NSWSF was 0.6 ml/min (Max: 1.32, Min: 0.14) in healthy group, and 0.28 ml/min (Max: 0.8, Min: 0.01) in patient group (p<0.001). 3) The lacrimal flow in Schirmer-1 test was 22.0 mm (Max: 30, Min: 8) in healthy groups and 5.26 mm (Max: 21, Min: 0) in patient group (p<0.001). 4) The correlation coefficient between the hardtack test and NSWSF was 0.56 (p<0.001). The correlation coefficient between the hardtack test and Schirmer-1 test was 0.51 (p<0.001). NSWSF was correlated with Shirmer-1 test but not significantly (r=0.254, p=0.075). In the hardtack test, the best balance between sensitivity and specificity was seen with a cut-off value of 120 seconds.
CONCLUSION
The Hardtack test is useful screening test to discriminate between subjects with normal and reduced salivary flow. The Hardtack test is easy to perform, inexpensive, imposes minimal discomfort on the subject with xerostomia and correlated well with the NSWSF and the Schirmer-1 test. So it can also be used as to monitor the Sjogren's syndrome before the salivary flow measurement or Schirmer-1 test.