Table 3.

Highest 5 and Lowest 5 VA Facilities with Adjusted Exposure to a Drug-Disease Interaction (iRx-DIS). The percentages indicate the proportion of individuals at a given facility with iRx-DIS exposure.

Rank	VISN*	iRx-DIS (%)	Adjusted iRx-DIS (%)†	95% CI	Top Condition-Drug Class Leading to iRx-DIS††
1	I	4.86	4.61	3.88-5.46	Chronic Renal Failure - NSAIDs
2	J	4.47	4.55	3.76-5.50	Dementia - Anticholinergics
3	K	4.41	4.42	2.52-7.64	Dementia - Anticholinergics
4	L	4.48	4.26	3.18-5.68	Dementia - Anticholinergics
5	J	3.76	4.26	3.20-5.66	Dementia - Anticholinergics
124	E	1.97	2.01	1.57-2.58	Dementia - Anticholinergics
125	M	1.78	1.91	1.30-2.81	Dementia - Anticholinergics
126	E	1.71	1.91	1.45-2.52	Dementia - Anticholinergics
127	A	2	1.87	1.28-2.72	Dementia - Anticholinergics
128	G	1.3	1.29	0.70-2.39	Dementia - Anticholinergics

^*To maintain confidentiality, each VISN is represented by a letter. Where the letters are the same, it indicates that the two VA facilities are located in the same VISN. VISN = Veterans Integrated Service Network.

^†Adjusted for all patient-level variables

^††Of patients with dementia with a drug-disease interaction, oxybutynin, a genitourinary antispasmodic, was the most commonly used anticholinergic medication. Contraindicated classes/medications for those with dementia include those that are highly anticholinergic (e.g., 1st generation antihistamines, skeletal muscle relaxants, antispasmodics), as well as tricyclic antidepressants.