World Workshop on Oral Medicine VIII: Development of a core outcome set for dry mouth: a systematic review of outcome domains for salivary hypofunction

Objective: To identify all outcome measures used to assess salivary gland hypofunction (i.e., objective measures used to determine actual changes in saliva quantity or to assess response to treatment of salivary gland hypofunction) and to group these into domains. Study Design: A systematic review including clinical trials and prospective or retrospective observational studies involving human participants with dry mouth, with any type of intervention where the objective assessment of salivary gland hypofunction was described. Results: Five hundred fifty-three studies involving 31,507 participants were identified. Most assessed salivary gland hypofunction and xerostomia (68.7%), whereas 31.3% assessed salivary gland hypofunction alone. Most studies investigated the “amount of saliva,” and the highest number of outcome measures were within the domain of “clinical/objective signs of salivary gland hypofunction.” Conclusions: Seven domains encompassing 30 outcome measures were identified, confirming the diversity in outcomes and outcome measures used in research regarding salivary gland hypofunction. Identified items will be used in conjunction with those identified regarding xerostomia to create a core outcome set for dry mouth quantification for use in future clinical trials, with the overall goal of improving the standardization of reporting, leading to the establishment of more robust evidence for the management of dry mouth and improving patient care.