Table 5.

Adjusted logistic regression on the likelihood of having drug combinations with risk of pharmacokinetic interactions among incident cases (N = 3,706)

	Odds Ratio (Confidence Interval) of
	Interaction risk of AED on NED			Interaction risk of NED on AED
	Any	High	High-Medium
White	1.00	1.00	1.00	1.00
AA	1.00 (0.80–1.26)	0.73 (0.5–1.06)	0.76 (0.58–0.998)	0.80 (0.63–1.03)
Hispanic	0.93 (0.68–1.26)	–	0.74 (0.51–1.06)	0.72 (0.52–1.01)
Asian	0.64 (0.43–0.96)	–	0.57 (0.35–0.93)	0.63 (0.41–0.96)
AI/AN	0.86 (0.47–1.57)	–	0.41 (0.17–0.99)	0.71 (0.36–1.38)
Non AA or White	–	0.61 (0.39–0.97)	–
Female	1.07 (0.91–1.27)	0.77 (0.59–1.02)	1.09 (0.89–1.34)	0.95 (0.79–1.14)
Age
66–74	1.00	1.00	1.00	1.00
75–84	1.16 (0.96–1.39)	0.90 (0.66–1.23)	1.13 (0.90–1.41)	1.16 (0.95–1.41)
85+	1.02 (0.83–1.25)	1.05 (0.75–1.48)	1.18 (0.92–1.50)	0.90 (0.72–1.13)
Comorbid conditions
0	1.00	1.00	1.00	1.00
1–3	2.14 (1.26–3.64)	2.82 (0.87–9.10)	2.16 (1.07–4.36)	2.08 (1.12–3.86)
4+	2.73 (1.61–4.64)	3.80 (1.19–12.2)	2.85 (1.42–5.71)	2.92 (1.58–5.38)
Neurologist close to diagnosis	0.56 (0.48–0.67)	0.66 (0.5–0.87)	0.61 (0.50–0.75)	0.64 (0.53–0.77)
LIS eligible	1.19 (0.96–1.47)	2.05 (1.36–3.09)	1.44 (1.10–1.88)	1.62 (1.27–2.07)
Region not Northeast	1.34 (1.08–1.65)	1.19 (0.83–1.69)	1.39 (1.07–1.80)	1.25 (0.99–1.57)
High poverty ZIP code	1.08 (0.92–1.27)	0.99 (0.76–1.31)	1.11 (0.91–1.34)	1.02 (0.85–1.21)

AED = antiepileptic drugs; NED = non-epilepsy drugs; High risk = potentially life threatening or liable to cause serious toxicity; Medium risk = significant risk but effects less marked or may be delayed; AA = African American; AI/AN = American Indian/Alaskan Native; LIS = Part D Low Income Subsidy