Table 3.

Spearman correlation between FPIR and 9 OGTT variables in relatives at risk for T1D in the DPT-1 study cohort

Metabolic variablesa	N	Spearman correlation coefficient	95% confidence limits		P valueb
Index60	194	-0.562	-0.651	-0.457	< 0.0001
C-peptide Index	194	0.544	0.437	0.636	< 0.0001
C-peptide 30-0 min	194	0.534	0.425	0.627	< 0.0001
C-Peptide AUC	194	0.484	0.368	0.585	< 0.0001
Sum of C-peptide	194	0.466	0.348	0.569	< 0.0001
Peak of C-peptide	194	0.436	0.315	0.544	< 0.0001
Fasting C-peptide	194	0.369	0.241	0.485	< 0.0001
Sum of glucose	194	-0.341	-0.460	-0.210	< 0.0001
Fasting glucose	194	0.030	-0.111	0.170	0.6758

Abbreviations: AUC, area under the curve; DPT-1, Diabetes Prevention Trial-Type 1 Diabetes; FPIR, first-phase insulin response; OGTT, oral glucose tolerance test; T1D, type 1 diabetes.

^a Insulinogenic index and oral disposition index could not be calculated in DPT-1 because samples for insulin testing were not collected during OGTTs.

^b Adjusted P values using the Benjamini-Hochberg method to control for false-discovery rates.