Table 3 EL-LR formula based on variables selected by the EL-NDI

CDelay: BSIDIII cognitive score < 85 at 24 months CA

Variables (n = 10)

\(In\left(\frac{p}{1-p}\right)=4.39-2.22{\text{a}}-3.71{\text{b}}+1.36{\text{c}}-2.56{\text{d}}-1.14{\text{e}}+0.28{\text{f}}-1.48{\text{g}}+0.34{\text{h}}+0.8{\text{i}}-0.15{\text{j}}\)

a. Motor BSIDIII score at 12 months

b. Cognitive BSIDIII scores at 12 months

c. Abdominal surgery

d. IPPV days

e. pH in 1st time blood gas

f. Oxygenation supply≧ 40%

g. Head circumstance at 6 months CA

h. Maternal education ≦ 12 years

i.  Body length at 6 months CA

j.  Hemodynamic significant PDA

MDelay: BSIDIII motor score < 85 at 24 months CA

Variables (n = 4)

\(In\left(\frac{p}{1-p}\right)=4.98-8.09{\text{a}}-3.31{\text{b}}+2.89{\text{c}}-1.66{\text{d}}\)

a. Motor BSIDIII scores at 12 months

b. Cognitive BSIDIII scores at 12 months

c. NICU days

d. PMA while discharge

CRegres: BSIDIII cognitive score declines ≧ 15 between 6 and 24 months CA

Variables (n = 4)

\(In\left(\frac{p}{1-p}\right)=-4.42+8.47{\text{a}}-1.04{\text{b}}-0.65{\text{c}}+0.23{\text{d}}\)

a. Cognitive BSIDIII scores at 6 months

b. Motor BSIDIII scores at 6 months

c. Maternal MgSO4 use

d. Parental education ≦ 12 years

MRegres: BSIDIII motor score declines ≧ 15 between 6 and 24 months CA

Variables (n = 4)

\(In\left(\frac{p}{1-p}\right)=-5.84+9.91{\text{a}}+0.52{\text{b}}+0.08{\text{c}}+0.007{\text{d}}\)

a. Motor BSIDIII scores at 6 months

b. Antenatal steroid use

c. Head circumference at admission

d. Prolonged rupture of membranes

CA 6-month height/head circumstance categorized in 8 parts based on WHO boy girl growth chart Z score (− 3Z, − 2Z, − Z, mean, Z, 2Z, 3Z); head circumstance at admission categorized in 8 parts based on INTERGROWTH-21st very preterm size at birth reference charts Z score (− 3Z, − 2Z, − Z, Mean, Z, 2Z, 3Z)

Note: \(p\) is the probability of outcomes