New Study - SubQ Alledgedly Leads To Lower HCT/E2/PSA Than IM Just Published

bennettjc · Apr 4, 2022

This data was first discussed here a year or so ago when it was released as a poster. It was now just published in a major urology journal.

Bascially it suggested that 75 or 100mg of "Xyosted" (SubQ enanthate) each week leads to lower HCT/E2/PSA than does 100mg of IM cypionate.

This is a poor study. The two groups were not randomized (one group was lower) and some of the authors are on the Xyosted payroll.

I have the full paper if you are interested:

Comparison of Outcomes for Hypogonadal Men Treated with Intramuscular Testosterone Cypionate versus Subcutaneous Testosterone Enanthate - PubMed

While IM-TC and SCTE-AI provide a significant increase in TT levels, SCTE-AI is associated with lower levels of post-therapy HCT and E2 compared to IM-TC after adjusting for significant covariates. SCTE-AI is an effective testosterone delivery system with a potentially preferable safety profile...

pubmed.ncbi.nlm.nih.gov

tareload · Apr 4, 2022

If you have the data or results I'm happy to take a look. Thanks for posting.

Abstract from above doesn't read the same as poster last year. Did the make the dosing equivalent, control for Cavg? Age between groups, etc?

If they control for stuff properly, we may be able to conclude something about Hct effect, peak/trough.

bennettjc · Apr 4, 2022

bennettjc said:
This data was first discussed here a year or so ago when it was released as a poster. It was now just published in a major urology journal.

Bascially it suggested that 75 or 100mg of "Xyosted" (SubQ enanthate) each week leads to lower HCT/E2/PSA than does 100mg of IM cypionate.

This is a poor study. The two groups were not randomized (one group was lower) and some of the authors are on the Xyosted payroll.

I have the full paper if you are interested:

Comparison of Outcomes for Hypogonadal Men Treated with Intramuscular Testosterone Cypionate versus Subcutaneous Testosterone Enanthate - PubMed

While IM-TC and SCTE-AI provide a significant increase in TT levels, SCTE-AI is associated with lower levels of post-therapy HCT and E2 compared to IM-TC after adjusting for significant covariates. SCTE-AI is an effective testosterone delivery system with a potentially preferable safety profile...

pubmed.ncbi.nlm.nih.gov

I meant to write "one group was YOUNGER"
Paper attached.

tareload · Apr 4, 2022

They should have consulted with a statistician and this paper should have been strongly flagged during peer review.

See Table 1.

Once you see the result in Table 2 you stop there. Going any further with linear regression (see Tables 3, 4, and 5) and a mix of one important categorical and other continuous variables is a big no no unless you look for potential interactions and covariance between age and TT.

What do the distributions for age, TT and Hct look like between the two groups? Normal, bimodal?

See Table 4. The authors conclude TRT modality is significant. Where's the potential interaction term between modality and age?

Would that be an important effect to test for given the way the study was set up?

Would the findings in this paper be materially important to how you should design the study?

Now go back and look at Table 1 again. How do the p-values for Hepcidin suppression vs serum TT level above compare with TT level in Table 1 of paper (note you'll have to transform the data in Table 1):

Kind of important to make sure you are isolating the effect you are trying to test. Is hepcidin suppression a lurking variable that wasn't properly controlled for in this study?

tareload · Apr 4, 2022

No discussion of potential age confounding in the Hct results? No discussion for how age may have played in PK profile for the subjects. Clearly age had a significant effect on trough TT. No curiousity on how it may also affect peak TT? Does fT or TT peak/trough matter in the context of E2/Hct mechanisms?

Simple to overlay the Hct, modality and age data distributions.