HOMA-IR: difference between revisions
Diff·revision 4 → 5·01:49, 4 Nov 2024
Difference between revision 4 and revision 5 of HOMA-IR. 4 lines changed; the page grew by 458 bytes.
| Revision 4 — 06:54, 23 Oct 2024 Chromatokid (talk) expand §Behaviour under weight loss and incretin therapy 1,827 bytes ±0 | Revision 5 — 01:49, 4 Nov 2024 A1c_Alder (talk) add category for laboratory medicine 2,285 bytes +458 | ||
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| 10 | Its appeal is that it requires one blood draw rather than a several-hour clamp. Its weakness is that it is a model-derived approximation from two values, inherits the poor standardisation of insulin assays, and describes hepatic rather than peripheral insulin resistance most directly.{{r|wallace2004}} | 10 | Its appeal is that it requires one blood draw rather than a several-hour clamp. Its weakness is that it is a model-derived approximation from two values, inherits the poor standardisation of insulin assays, and describes hepatic rather than peripheral insulin resistance most directly.{{r|wallace2004}} |
| 11 | 11 | ||
| + | 12 | The authors of the model have themselves written about its misuse, and the practical conclusion is that it tracks change within an individual on a consistent assay better than it classifies individuals against published thresholds.{{r|wallace2004}} | |
| + | 13 | ||
| 12 | == Calculation and the two forms == | 14 | == Calculation and the two forms == |
| 13 | The original linear approximation is | 15 | The original linear approximation is |
| ⋮ | ⋮ | ||
| 16 | 18 | ||
| 17 | A revised non-linear computer model, HOMA2, was published later and gives different values, particularly at the extremes. The two are not interchangeable, and a figure quoted without saying which was used is ambiguous.{{r|wallace2004}} | 19 | A revised non-linear computer model, HOMA2, was published later and gives different values, particularly at the extremes. The two are not interchangeable, and a figure quoted without saying which was used is ambiguous.{{r|wallace2004}} |
| + | 20 | ||
| + | 21 | Unit conventions add a second ambiguity: glucose in mg/dL requires a different divisor, and insulin in pmol/L a further conversion. A published cut-off carries its unit convention with it.{{r|matthews1985}} | |
| 18 | 22 | ||
| 19 | == References == | 23 | == References == |