not much to it : (1) in addition to the glucose you also need an insulin or c-peptide measurement. For purposes of IR checking the authors recommend insulin which should be in the range 2-17 uU/mL (micro-units per milliliter) (2) make sure both are fasting tests as the levels can vary significantly around meals (3) after converting glucose from mg/dL just multiply the two together and divide by 22.5 to get your HOMA1 index. For HOMA2 you have to download the calculator from oxford
http://www.dtu.ox.ac.uk/homacalculator/index.php
either as an executable or an an excel control.
If it's an issue it seems more likely to show up as non-response than relapse but definitely a good thing to rule out. Glucose 88 looks pretty good. Mine tends to be at the high end of normal and broke past 100 last year triggering a slow down in my fig-bar rate which caused it to coast back to 92 - but insulin is way low.
Good thread
I read this with interest and have pulled prior blood work to see what it tells me. My glucose is easy -- it is written as Glucose, Serum or GLU. It is written in mg/dL so requires modification, per Willing. I am having a problem finding any insulin resistance tests. I have a book -- "Mosby's Manual of Diagnostic and Laboratory Tests " which give what I thought were all the blood tests. Under Insulin we have assay, autoantibody (IAA), blood glucose, C-peptide, and some growth factor tests. So what, pray tell is an insulin resistance test, and is it only run when there are high level glucose tests?
I am always searching for reasons I relapsed. Glucose is in range -- about 88 last time -- but I would like to calculate this insulin resistance, . If there is another test to ask for, I would like to ask my doctor for it.
frijole
did a Dr. diagnose IR? that seems surprising with the numbers you posted. Unlike say fibrosis there are reliable gold-standard tests for IR that measure changes in actual insulin/glucose dose/response levels instead of approximating them as HOMA does, so that seems the way to go if you want a definite answer.
Re homa1 vs homa2 yes agreed that essentially all studies have applied homa1 regardless of the fact the index systematically gives artificially high IR scores. To keep from comparing apples with oranges it seems best to use HOMA1 for comparison with published studies and HOMA2 for a more reliable, corrected, 'absolute' indication of whether IR is an issue. For example, in one of the main IR vs SVR studies:
"Insulin resistance impairs sustained response rate to peginterferon plus ribavirin in chronic hepatitis C patients."
http://www.ncbi.nlm.nih.gov/pubmed/15765399
the average HOMA1 was 2.36 among SVRs and 3.76 among non-SVRs.
They also found better SVR rates among those with lower-than-average HOMA1, so there seems to be some motivation for pushing down your HOMA1 regardless of whether you're IR - though given HCV's known effect on glucose metabolism the low HOMA1 group could also have had something else going for them - eg low VL.
(also sorry about my mistake in post above, not sure why I wrote median HOMA1 of 2.7 among healthy volunteers, that should be average).
HOMA1-IR = (FPI (mU/L) x FPG (mmol/L))/22.5
HOMA1-%B = (20 x FPI (mU/L))/(FPG (mmol/L) – 3.5)
Where FPI is fasting plasma insulin and FBG is fasting plasma glucose; to convert mg/dL to mmol/L, simply divide by 18.
The original model did not account for differences between hepatic and peripheral insulin sensitivity, increases in insulin secretion or decreases in hepatic glucose production for plasma glucose concentrations above 180 mg/dL, renal glucose losses, or the contribution of circulating proinsulin. An updated HOMA model (HOMA2) has since been created, however it is a computer model and has no simple equation but it adjusted to account for these variations. It models insulin sensitivity (HOMA2-%S) where 100% is normal which is the reciprocal of insulin resistance (100/S%). In addition, the original HOMA model uses equations that were calibrated to insulin assays used in the 1970’s which result in underestimation of %-S and overestimation of %-B. With knowledge of these differences, it is therefore important when evaluating studies to determine whether the HOMA formula or the computer-based HOMA was used to quantify insulin resistance and beta-cell function.
Most studies systematically use HOMA1 for data.
Mean being the average, median being the middle number in a set, & mode being the # that occurs most often.
It was confirmed that I'm IR. I'm just slightly into that range. Should be able to sort it out a lot easier that way.
the free-access paper linked above
http://www.ncbi.nlm.nih.gov/pubmed/10868826
measured median HOMA1 of 2.7 among "490 healthy nondiabetic volunteers".
Also HOMA1 and HOMA2 were developed by the same research group at Oxford with HOMA2 being an improvement/refinement over HOMA1. As noted in the quote above (that paper is also free access) the group that developed the test is well-aware that HOMA1 systematically underestimates insulin sensitivity, a problem they believe is fixed in HOMA2. Your HOMA2 score is very close to 1. Insulin resistance may be a problem for you, but it doesn't look that way from the numbers. Confirming with a Dr. that it's a problem before assuming there's something to fix may be a good idea.