Table 2

Comparison of metabolic parameters by glucose response curve shape

AllMonophasicBiphasicContinuous riseOverall p valueM vs BM vs CB vs C
P valueP valueP value
n31082107172829
HbA1c (%)7.50 (0.48)7.49 (0.48)7.49 (0.48)7.52 (0.49)0.0320.9000.0220.613
HbA1c (% mmol/mol)58.4 (5.3)58.4 (5.2)58.4 (5.2)58.7 (5.4)0.0320.9000.0220.613
Fasting glucose (mmol/L)8.42 (1.71)8.48 (1.73)8.24 (1.50)8.31 (.70)0.7340.7030.9840.778
2-hour glucose (mmol/L)15.98 (3.06)15.42 (2.98)15.63 (2.71)17.46 (2.85)<0.0010.965<0.001<0.001
Peak glucose (mmol/L)17.69 (2.87)17.87 (2.88)16.40 (2.42)17.48 (2.85)<0.001<0.001<0.001<0.001
Proportions with peak glucose at OGTT time-point, n (%)<0.001<0.001<0.001<0.001
 30 min21 (0.7)9 (0.4)12 (7.0)0 (0.0)
 60 min793 (25.5)721 (34.2)61 (35.5)11 (1.3)
 90 min1536 (49.4)1377 (65.4)19 (11.0)140 (16.9)
 120 min758 (24.4)0 (0.0)80 (46.5)678 (81.8)
Mean time to peak glucose (min)89.3 (21.7)79.5 (14.6)89.1 (31.5)114.1 (12.9)<0.001<0.001<0.001<0.001
Mean incAUCglu (mmol/L)6.3 (1.6)6.5 (1.5)5.3 (1.6)5.9 (1.5)<0.001<0.001<0.001<0.001
HOMA2-S model (%)56.5 (40.6)53.2 (38.)60.9 (41.5)63.9 (45.6)0.0770.9790.0580.588
Fasting insulin (pmol/L)128.9 (89.0)135.3 (91.7)119.6 (81.4)114.5 (81.4)0.7420.9760.7550.841
Insulinogenic index (nmol/mol)*36.5 (30.2)36.4 (29.0)44.1 (37.0)35.3 (31.5)<0.001<0.0010.327<0.001
Late insulin response (pmol/mol)*40.4 (34.8)42.4 (36.7)46.3 (39.8)34.0 (27.2)<0.0010.033<0.001<0.001
incAUCins/incAUCglu (nmol/mol)*39.1 (31.5)40.5 (32.6)45.9 (36.5)34.0 (23.6)<0.0010.0010.008<0.001
Fasting C peptide (nmol/L)1.35 (0.56)1.40 (0.57)1.26 (0.49)1.23 (0.53)0.0600.6560.0490.927
C peptide index (nmol/mmol)*0.135 (0.096)0.134 (0.089)0.155 (0.119)0.133 (0.106)0.0030.0020.6460.014
incAUC-CP/incAUCglu (µmol/mol)*0.19 (0.11)0.19 (0.11)0.22 (0.13)0.17 (0.09)<0.0010.002<0.001<0.001
C peptide/insulin (µmol/pmol)12.5 (4.6)12.3 (4.4)12.7 (4.4)13.0 (5.1)0.0700.4420.0750.999
  • Mean (SD).

  • All comparisons were adjusted for sex, age, race, BMI, diabetes duration, eGFR, and metformin dose.

  • *Insulin and C peptide responses were further adjusted for HOMA2-S.

  • B, biphasic shape; BMI, body mass index; C, continuous rise shape; eGFR, estimated glomerular filtration rate; HbA1c, hemoglobin A1c; HOMA2-S, homeostasis model of insulin sensitivity; incAUC-CP, incremental area under curve C peptide; incAUCglu, incremental area under curve glucose; incAUCins, incremental area under curve insulin; M, monophasic shape; OGTT, oral glucose tolerance test.