Limitation of the homeostasis model assessment to predict insulin resistance and beta-cell dysfunction in older people.
BACKGROUND
Studies in older people have shown inconsistent agreement between homeostasis model assessment of insulin resistance (HOMA-IR) and dynamic measures of insulin action and have not evaluated HOMA beta-cell.


OBJECTIVE
We compared measures of insulin sensitivity and beta-cell function from the frequently sampled iv glucose tolerance test (FSIGT) to HOMA models. DESIGN/PATIENTS/SETTING/INTERVENTION: Two hundred fourteen young and old with normal glucose tolerance (NGT) and old with impaired glucose tolerance (IGT) participated in a retrospective analysis of FSIGT data in a university medical setting.


METHODS
Sensitivity to insulin (S(I)) and acute insulin response to glucose (AIRg) from FSIGT were compared with HOMA models.


RESULTS
S(I) and HOMA-IR measures identified similar patterns of increasing insulin resistance in the two older groups, compared with younger people with NGT, with the greatest degree of insulin resistance in older people with IGT (P < 0.05 vs. young and old NGT for both S(I) and HOMA-IR). Agreement between HOMA-IR and S(I) was moderate (weighted kappa = 0.51). AIRg was similar in young and old NGT but was markedly decreased in old IGT (P < 0.05 vs. young and old NGT). HOMA-beta-cell was similar in the three groups. Agreement between HOMA beta-cell and AIRg was weak (weighted kappa = 0.35).


CONCLUSIONS
HOMA-IR may detect age-related insulin resistance when comparing large populations of older people. However, dynamic testing appears to be necessary to quantitate diminished insulin secretion in older people.
Chang
Annette M
AM
University of Michigan, 5570 MSRB II, 1150 West Medical Center Drive, Ann Arbor, MI 48109-0678, USA. annchang@umich.edu
Smith
Marla J
MJ
Bloem
Cathie J
CJ
Galecki
Andrzej T
AT
Halter
Jeffrey B
JB
Supiano
Mark A
MA
D000328:Adult; D000367:Age Factors; D000368:Aged; D000369:Aged, 80 and over; D001786:Blood Glucose / Q000378:metabolism; D005260:Female; D018149:Glucose Intolerance / Q000175:diagnosis / Q000378:metabolism; D005951:Glucose Tolerance Test; D006706:Homeostasis; D006801:Humans; D007328:Insulin / Q000008:administration & dosage / Q000097:blood; D007333:Insulin Resistance / Q000502:physiology*; D050417:Insulin-Secreting Cells / Q000378:metabolism*; D008297:Male; D008875:Middle Aged; D012189:Retrospective Studies
D001786:Blood Glucose; D007328:Insulin