Where Dysphagia Begins: Polypharmacy and Xerostomia
Background: Xerostomia, the subjective sensation of dry mouth, contributes to dysarthria, dysphagia, and diminished quality of life. Polypharmacy is a known and modifiable risk factor for xerostomia. The objective of this study was to evaluate the prevalence of dry mouth, the relationship between dry mouth and other oral conditions, and the impact of polypharmacy on dry mouth.
Methods: This study was a retrospective cross-sectional study of all patients seen in fiscal year (FY) 2015 (October 1, 2014 to September 30, 2015) at the VA Palo Alto Health Care System (VAPAHCS), a tertiary care US Department of Veterans Affairs (VA) hospital. Patients diagnosed with xerostomia were identified using ICD-9 codes (527.7, 527.8, R68.2) and Systemized Nomenclature of Medicine Clinical Terms (SNOMED CT) codes (87715008, 78948009).
Results: Of all the patients seen at VAPAHCS during FY 2015, 138 had a diagnostic code for xerostomia; of those patients, 84 had at least 1 documented speech, dentition, or swallowing (SDS) problem, and 55 (39.9%) were taking ≥ 12 medications, more than twice as many patients as in any one of the other groups studied (0-2, 3-5, 6-8, and 9-11 medications taken). Although 4,971 total patients seen at VAPAHCS had documented SDS problems during FY 2015, of those patients only 77 (1.5%) had an additional recorded diagnosis of xerostomia.
Conclusions: Heightened physician awareness regarding the signs and symptoms of and risk factors for xerostomia is needed to improve health care providers’ ability to diagnose dry mouth. Polypharmacy also must be considered when developing new strategies for preventing and treating xerostomia.
Additionally, past polypharmacy studies have acknowledged an inability to tell whether xerostomia is mainly due to medications or to underlying medical conditions. For example, for emphysema, ß-adrenergic stimulation from bronchodilators could cause dry mouth by thickening saliva and decreasing salivary volume, but the pathophysiology and/or cardinal symptoms of emphysema, including chronic obstructive pulmonary disease-associated tachypnea, might contribute independently to dryness.
Though we can make inferences based on the medications taken by this cohort (eg, those taking antihypertensives have high blood pressure), this dataset did not explicitly detail comorbid conditions and ICD codes for chronic diseases that commonly arise with xerostomia. Those conditions, however, are of great clinical importance. Diabetes mellitus, HIV/AIDS, and, classically, Sjögren syndrome, all are known to cause dry mouth.43 Identifying new conditions that co-occur with xerostomia would allow clinicians to describe the root causes of and risk factors for dry mouth and SDS conditions in greater detail. Patients with dry mouth without SDS problems in this dataset are of particular interest as closer examination of their medications and comorbid conditions could help us understand why some individuals and not others develop SDS problems. The subjects of how comorbidities contribute to dry mouth and how their influences can be judged independently from the effects of medications are of great interest to us and will be investigated rigorously in our future studies.
Conclusions
In this cohort, few patients with SDS problems had documentation of a concomitant xerostomia diagnosis. This could represent a true infrequency of dry mouth or more likely, an underrecognition by clinicians. Heightened physician awareness regarding the signs and symptoms of and risk factors for xerostomia is needed to improve providers’ ability to diagnose this condition.
In particular, polypharmacy should be a major consideration when evaluating patients for xerostomia. This continues to be an important area of research, and some of the latest data on polypharmacy among older patients were compiled in a recent meta-analysis by Tan and colleagues. The authors of that systematic review reiterated the significant association between salivary gland hypofunction and the number of medications taken by patients. They also advocated for the creation of a risk score for medication-induced dry mouth to aid in medication management.44 Per their recommendations, it is now as crucial as ever to consider the numbers and types of medications taken by patients, to discontinue unnecessary prescriptions when possible, and to continue developing new strategies for preventing and treating xerostomia.
