@goseve @wondering1 @gravity3 @lbrown742

Study 1 authored by Cosman/Lindsay
https://onlinelibrary.wiley.com/doi/10.1359/jbmr.2001.16.5.925
This was a small randomized trial with 52 patients. About half received 25mcg of teriparatide plus HRT daily for 3 years, while the other half continued HRT alone. After the 3 years, teriparatide was stopped but HRT was continued for an additional year. Results showed significant bone density gains with the combination, and those gains were maintained during the 1yr follow-up on HRT alone.

Study 2 authored by Ste-Marie
https://onlinelibrary.wiley.com/doi/10.1359/JBMR.051020
This was a larger randomized trial with 247 patients. About one half received 40mcg of teriparatide plus HRT for a median of about 14mo, while the other half received HRT plus placebo injections. The combination group showed significantly greater bone density gains than HRT alone. However, this study did not include a follow-up period after teriparatide was stopped, so we don't have info on whether or how those gains were maintained afterward.

I have a few thoughts and would love to hear opinions from everyone:

1. Neither study included a group taking teriparatide alone (without HRT), so we can't tell from these studies whether HRT + teriparatide was better than teriparatide by itself.

2a. The teriparatide doses in both studies (25mcg and 40mcg) were higher than the standard Forteo dose (20mcg). This means the results may not directly apply to a regimen using 20 mcg teriparatide because 2b 👇

2b. Clinical studies had shown that 40mcg teriparatide produces significantly larger bmd gains than the 20mcg dose

3. Neither study specified dose or form of estrogen but likely used what was considered a "standard" dose at the time (such as oral conjugated estrogen - Premarin 0.625 mg or equivalent)

4. Only the smaller study by Cosman/Lidsey had HRT-alone as follow-up after teriparatide. While the results were encouraging, the small size and short follow-up period make it hard to draw firm long-term conclusions.

Because of those differences in dosing and study design, we can't directly assume that goseve’s specific combination (20mcg teriparatide in Forteo + 0.075 mg estradiol patch) will produce the same results. That said, the Cosman/Lidsey study does suggest that HRT provides some level of bone protection during and after anabolic therapy.

I used Cosman’s paper as the basis for my discussion with my endo. Looking ahead, my dream scenario would be to stay on HRT continuously and simply add Forteo (or Tymlos) whenever I need a little BMD boost. Whether that would actually work is another question entirely - but a person is allowed to dream, right? 😊