Medication and dry mouth: Findings from a cohort study of older people

Objectives: The aim of this study was to examine the association between me dication exposure and (1) unstimulated whole-salivary flow rate and (2) the severity of xerostomia among older people while adjusting for multiple med ication use. Methods: Data were obtained from participants remaining at the five-year follow-up phase of a cohort study of community-dwelling older So uth Australians Medication exposure information was available at baseline a nd at five years, enabling examination of the effects on dry mouth of long- term exposure to medications. At the five-year follow-up, unstimulated sali vary flow was estimated using the spit method, and xerostomia severity was estimated using the I I-item Xerostomia Inventory. Because of the potential difficulties posed by polypharmacy, a two-stage analytical approach was em ployed (I) Classification and Regression Tree (CART) analysis was used as a n exploratory device to elucidate the relationships among the dependent and independent variables and (2) linear regression analysis was used as a com plementary procedure. Results: Unstimulated flow rate was lower among indiv iduals who were female or taking antidepressants at both baseline and five years, and higheramong smokers or people who were taking hypolipidemic drug s. Xerostomia severity was higher among females, or individuals taking: (I) an anginal at baseline and five years, (2) an anginal without a concomitan t betablocker at five years, (3) thyroxine and a diuretic at five years, or (4) antidepressants or antiasthma drugs at both baseline and at five years . Conclusions: These results suggest that polypharmacy can be accounted for to a certain extent by using CART analysis in conjunction with more conven tional approaches; and that the relationship between medications and dry mo uth bs: a complex one, and differs according to which aspect of dry mouth i s being examined.