Methods
This is a retrospective cross-sectional study of all outpatient visits 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. This study was approved by the Stanford University Institutional Review Board. All patients diagnosed with xerostomia in the 1-year study period were identified using ICD-9 diagnosis codes for dry mouth or disturbance of salivary gland secretion (527.7, 527.8, R68.2) and Systemized Nomenclature of Medicine Clinical Terms (SNOMED CT) codes covering dry mouth, xerostomia, aptyalism, absent salivary secretion, and disturbance of salivary secretion (87715008, 78948009). Data analysts in the VA Office of Business Analytics assisted in gathering data from the Veterans Information Systems and Technology Architecture (VistA) electronic health record.
The statistical analysis of that data was performed using Microsoft Excel. Age and gender distributions were determined for the patients. The relationship between xerostomia and the number and types of medications taken by patients also was examined. A previous Swedish study examining the link between dry mouth and quantities of medications used a scale ranging from 0 to ≥ 7 medications.16 The scale for this study was made wider to include the following groups: 0-2, 3-5, 6-8, 9-11, and ≥ 12 medications. Items that do not have xerogenic risks, such as medical supplies (eg, gloves, syringes, etc) and topical medications, were excluded from the analysis. Finally, the number of subjects with comorbid problems with speech, dentition, or swallowing (SDS) was recorded. Non-VA medications were included to capture any self- or externally prescribed xerogenic medications.
Results
Of the patients seen at VAPAHCS during FY 2015, 138 had a diagnostic code for xerostomia, including 129 men (93.5%) and 9 women (6.5%). The average (SD) age of this xerostomia cohort was 69.3 (12.6) years, and the 3 most common age groups were 60 to 69 years (37.7%), 70 to 79 years (28.3%), and 80 to 89 years (13.0%) (Table 1). Of those 138 patients with a xerostomia diagnosis, a majority (84; 60.9%) had at least 1 documented SDS problem (Table 2). Conversely, during FY 2015, although 4,971 patients seen at VAPAHCS had documented SDS problems, only 77 (1.5%) had a recorded diagnosis of xerostomia.
Of the 138 patients with xerostomia, 55 (39.9%) were taking ≥ 12 medications, more than twice as many patients as in any of the other groups studied (0-2, 3-5, 6-8, and 9-11 medications taken) (Table 3). On average, each patient with xerostomia filled prescriptions for 10.4 (SD, 7.2) different drugs. In this cohort of 138 patients diagnosed with xerostomia, antihypertensive medications or analgesics were taken by > 50% of patients, while statins, psychiatric medications, antibiotics, proton pump inhibitors, or drugs known to have anticholinergic activity were taken by > 40%. Antihistamines, anticonvulsants, diuretics, or inhaled respiratory agents were used by > 20% of the patients in this cohort (Table 4).
Data on each individual medication were split into 2 categories: the percentage of patients that filled ≥ 1 prescription for that drug, and the total number of prescriptions filled and/or refilled for that drug (ie, including all fills and refills made by individual patients). The 5 most widely used medications in this cohort were omeprazole (39.1%), docusate sodium (29.7%), gabapentin (29.7%), aspirin (27.5%), and hydrocodone/acetaminophen (26.1%) (Table 5). The 5 prescriptions that were cumulatively most filled and/or refilled were omeprazole (128), sildenafil citrate (108), gabapentin (101), hydrocodone/acetaminophen (100), and oxycodone (92) (Table 6). Though sildenafil citrate and oxycodone were among the most-filled prescriptions, these were not included in Table 5 as neither was taken by > 15% of the patients studied. These prescriptions were filled multiple times by a small subset of patients.
Regarding treatment for dry mouth, artificial saliva spray was one of the most widely used (23.2%) and the seventh most-filled prescription within this cohort (86). The only other medication taken by > 15% of patients in a formulation other than a tablet or capsule was chlorhexidine, a germicidal mouthwash used to improve oral care.
Also, 30 (21.7%) patients with a documented xerostomia diagnosis had a history of substance misuse involving use of ≥ 1 of tobacco, alcohol, marijuana, or other illicit drugs.