Table 3 Threshold effect analysis of average blood glucose (mmol/L) with Glasgow coma score at 6 months and 5 years using piecewise linear regression

Glasgow coma score (GOS)

β (95% CI) P value

β (95% CI) P value

Model I

 A linear inflection

− 0.09 (− 0.16, − 0.02) 0.0095

− 0.09 (− 0.17, − 0.01) 0.0228

Model II

Inflection point (K)

8.88

8.81

 < K

0.26 (0.09, 0.43) 0.0032

0.37 (0.18, 0.57) 0.0002

 > K

− 0.34 (− 0.46, − 0.21) < 0.0001

− 0.40 (− 0.54, − 0.26) < 0.0001

Log likelihood ratio tests

< 0.001

< 0.001

95% confidence interval of Inflection point

7.43, 9.74

7.43, 9.48

Favorable outcome (GOS ≥ 4)

OR (95% CI) P value

OR (95% CI) P value

Model I

 A linear inflection

0.85 (0.75, 0.97) 0.0117

0.87 (0.77, 0.98) 0.0272

Model II

Inflection point (K)

6.58

9.74

  < K

5.44 (2.01, 14.72) 0.0008

1.68 (1.29, 2.19) 0.0001

  > K

0.70 (0.59, 0.83) < 0.0001

0.30 (0.18, 0.48) < 0.0001

Log likelihood ratio tests

< 0.001

< 0.001

95% confidence interval of inflection point

6.41, 7.15

8.97, 10.41