The Oral Symptom Assessment Scale (OSAS): criterion validation with the EORTC QLQ-OH15 and reliability testing.

Purpose: The aim of this study was to investigate the criterion validity and reliability of the Oral Symptom Assessment Scale (OSAS) in patients with advanced cancer receiving specialist palliative care.

Methods: To examine criterion validity, participants completed the OSAS, EORTC QLQ-C30 and EORTC QLQ-OH15. Twenty-four hours later participants repeated the OSAS to investigate test-retest reliability.

Results: 54 participants were recruited (median age 70; range: 35- 93 years). 51 complete datasets were obtained. Cohen's kappa test was used to evaluate the agreement for the presence / absence of symptoms on the OSAS on the first and second days (test-retest reliability). This analysis showed values of moderate and higher for agreement for all symptoms. All kappa values were statistically significant. The test-retest reliability for symptom severity, frequency and distress was assessed using Intraclass Correlation Coefficient. Spearman's rank correlation coefficients were used to evaluate agreement between similar questions on the OSAS from day one and the EORTC QLQ-OH15 also on day one to examine criterion validity.

Conclusion: This study supports the validity of the OSAS, and provides evidence for the reliability of this novel oral symptom assessment tool, in patients with advanced cancer. Further research is needed to corroborate the findings of this study.

Trial Registration: CancerTrials.gov registry registration no.: PM202166.