Table 2.

Characteristics associated with cumulative incidence of epilepsy (logistic regression as of last follow-up), and development of seizures adjusted for age of onset (Cox regression analysis)

Variable	n for Logistic regression	OR	95% CI	OR Sig.	n for Cox regression	HR	95% CI	HR Sig.
Older age at recruitment	866	1	1.0–1.1	0.013
Hospitalized frequently (>2 per year)	866	2.7	1.8–3.9	<0.001	769	1.6	1.3–1.9	<0.001
Diagnosed after 75th percentile	866	2.3	1.5–3.7	<0.001	769	1.3	1.1–1.6	0.047
Diagnosed between median and 75th percentile	866	2	1.1–3.6	0.015
Frequent hyperventilation	866	1.8	1.2–2.7	0.003	769	1.2	0.9–1.5	0.055
Frequent breath-holding	866	1.9	1.1–3.3	0.022
Bradykinesia	866	2.5	1.3–4.7	0.004	769	1.6	1.3–2.0	<0.001
Scoliosis	866	1.6	1.1–2.4	0.016
Unable to ambulate	866	1.6	1.1–2.5	0.022	769	1.4	1.1–1.7	<0.001
Severe dystonia					769	1.3	1.0–1.6	0.024
Frequent stereotypies					769	0.8	0.7–1.0	0.062
Gastrostomy feeding	866	2	1.0–4.0	0.040	769	1.4	1.1–1.8	0.002
Aggression	866	0.5	0.3–0.8	0.009	769	0.6	0.5–0.9	0.003
Role/social limitations – physical	665	0.9	0.8–1.0	0.024
Behaviour	665	1.5	1.1–2.0	0.009
Mental health	665	0.8	0.5–1.0	0.023
Bone fractures	866	1.5	0.9–2.6	0.091
Hyperreflexia	866	1.4	1.0–2.1	0.062
Some verbal communication (babbling or words)					769	0.9	0.7–1.0	0.101

Non-significant results or results that trended to significant association are in bold. Blank cells indicate that variable did not meet minimal P-value for inclusion in regression equation. CI = confidence interval; HR = hazard ratio; OR = odds ratio; Sig. = Significance of p-value.