Table 2 Effect of age of onset

Taghred [19]

–

12 months

 < 1 year

 > 1 year

Age of onset

 < 1 year: 70/40

 > 1 year:23/53

OR: 4.0

p < 0.001

Age of onset lesser than 1 year is associated with an increased risk of drug resistance

Jeong [20]

Median (IQR):

5 (3–7.2) months

–

 < 1 year

 > 1 year

650/896

OR 1.9 (1.4–2.5) p < 0.001

Age of onset of less than 1 year increases the risk of drug resistance

Rawat [22]

Median(IQR): 15 (0–56) months

12 months

5 years

581/475

OR 2.02 (1.31–3.13) p = 0.0016

Age of Onset younger than 5 years is associated with increased risk for drug resistance or recurrence

Chen [18]

Mean (SD)

22.18 (± 1.38)years

4–9 years

–

41/100

2.508 (0.270, 23.316) p = 0.419

Age of onset is not associated with drug resistance

Berg [23]

–

 ≥ 10 years

 < 10 years

2–5 years

205/311

–

–

Berg [24]

The group followed < 10 years: 7.0 (4.2)

Group followed ≥ 10 years: 5.5 (4.1)

 ≥ 10 years

 < 10 years

–

347/266

Age of onset < 2 Hazard ratio: 1.000

Age of onset 2–5 Hazard ratio: 0.72 (0.48, 1.11)

Age of onset 5–10 Hazard ratio: 0.78 (0.52, 1.18)

Age of onset 10 + Hazard Ratio: 0.50 (0.30, 0.82)

Age of onset of less than 2 years increases the likelihood of drug resistance

Karaoglu [25]

Mean

Drug-resistant: 1.85 years

Drug receptive: 4.92 years

Median 46 months (range: 28–126 months)

–

177/281

p < 0.001

Univariate analysis

There is an association between the Early age of Onset and the development of drug-resistant epilepsy

Senem [28]

Range, intractable group: 0–1

Control group: 1–5

4 years

 > 1 year

 < 1 year

61/180

Odd ratio

Age < 1: 9.43 (3.66–24.30)

1–4 years: 1.79 (0.65–4.89)

5 and above: 1.04 (0.11–9.91)

p = 0.001

Age of onset of less than one year was found to be associated with an increased risk for intractable seizure

Lattanzi [26]

Mean (± SD)

Overall = 56.7 (± 14.9)years

Refractory group = 52.1 (± 15.3)years

Responsive group = 57.8 (± 14.7)years

Median (range)

5 (3–9) years

–

29/130

Multivariate

OR = 0.97

p = 0.044

There is an association between younger age of stroke onset and the development of drug resistance post-stroke epilepsy

Ramos-Lizana [27]

4.8 years (± 3.8 SD)

Mean used

Mean (± SD) (range)

76.2 (± 35.2 SD) month (24–139)

 > 1 year

30/313

Univariate HR = 4.9 p = 0.000

Multivariate HR = 2.6 p = 0.051

Age of onset lesser than 1 year was found to be associated with refractory epilepsy with univariate analysis and almost associated with multivariate analysis

Tripathi [29]

Mean(± SD):

Case = 5.18 (± 7.62)

Control = 5.62 (± 9.18)

–

 < 14 years

 > 14 years

200/200

Multivariate analysis

Age of onset < 14 OR = 3.09 + p < 0.005

There is an association between an age of onset of less than 14 years and the development of intractable epilepsy

Sara [21]

Mean ± SD 31 ± 21

Mean 9.4 years SD (4.2)

Median 8.1 years range (5.0–23.1)

17 year

143/43

–

Age of onset does not predict drug resistance