Are dual residency/PhD programs similar to DVM/PhD programs, in that the research you do will most likely be low impact and pushed too quickly? I know you did your residency first, and now are pursuing your PhD separately. Did you consider any dual programs when you were first looking into residency?
Ok here we go.
Firstly, the combined residency/PhD programs are almost all in pathology, lab animal medicine, and things like micro/pharm....they are very uncommon (I've never actually heard of any but I suppose there could be some) in more clinical specialties like internal med and the like. So that limits the pool a little bit but also, like Minnerbelle said, gives you more opportunity to work in higher impact areas away from clinical medicine.
In terms of structure, the majority are such that you spend your first two years in residency like any other normal resident - you might rotate through a few labs and get exposed at most. In your third year, you start taking less clinical duty and spending more time studying for boards and, if you're in a combined program, getting into your actual research lab and doing stuff. So it is a little less broken up. However, not all programs are like this - some of them have you start research as early as your first year, which I don't think is a very good idea but that's just my opinion. Some programs also will not allow you to take boards until after you are done with both the residency portion AND the PhD, which I also don't think is that great of an idea because after 3-4 years of research, your diagnostic skills are going to be diminished. However these seem to be the minority.
I was actually in a combined program like I said. It is actually very uncommon to find a pathology residency that is NOT a combined program these days, especially anatomic. However, you were not "locked in" - if you desperately wanted to go somewhere else or changed your mind and wanted to go into industry or something, you could go. They wanted us to be happy and if that meant moving on, so be it. Then again, I was in an exceptionally supportive program.
In terms of research impact, it is really all over the board. I know some people doing animal models of human disease and some doing more veterinary-focused research, the latter of which being of lesser impact because there are simply FAR fewer funding opportunities for veterinary (i.e. animal focused) research. A lot of it is getting into the right lab with the right PI.
Of course, this also depends on your ultimate goal. Most of my colleagues in the same position as me want to go into academic jobs that are heavily teaching and diagnostics oriented, with maybe only collaborative research on the side. So the pressure to produced loads of high impact work is slightly less for us than it would be if we wanted to actually do research primarily and have our own labs.
Something that I feel needs to be emphasized in biomedical research is that something like 70% of PhDs do postdocs (and this will include DVM/PhDs since research institutions don't give much more than half a crap about your DVM because it is a clinical degree, not a research degree - it is a feather in your cap, sure, but it doesn't make you a better grant writer, publisher, or researchers which is what they care about for research faculty. (Funny story just to give people an idea also about what high-end research institutions think of your DVM - I applied to two prestigious PhD program at institutions unaffiliated with veterinary schools as "backups" in case I didn't get a residency. And was rejected from both. Despite having pubs and experience under my belt. I was pretty appalled because I was always under the impression that research institutions wanted DVMs to get involved and would jump at the chance to train one. Maybe bad luck, but that stuck with me)
E.g. Data from 2011, but look at Life Sciences:
Additionally, the number of PhDs who actually end up running their own labs and tenured professors in biological science is TINY compared to the number of PhDs awarded
Admittedly yes, this BIOLOGY and not biomedical science, the latter of which is better and has something like 20% of PhD holders getting to tenure-track positions eventually (eventually as in after 6 years of PhD work and 3-4 years of postdoc work and probably a non-tenure track position or two) - however a lot of this depends on impact, and as straight biology research tends to be less impactful than biomedical, and veterinary/animal related research (which a lot of DVM/PhD student do) is less impactful than human-centric biomedical research, it's likely comparable or at least in between - so a risky return on investment.
In summary.....I know I sound like total doom and gloom here. I know I sound like I am dissuading people from doing the DVM/PhD period. That isn't what I am doing here. I am trying to inject some reality in here because like many people in that track I was fed all the lines about how there are so many jobs for DVM/PhDs and everyone will want you.....and
if you sticking with teaching positions and certain industry fields, that may be true in certain circles...but if you really want a research-heavy career and to run your own lab and things like that there is a LOT more in play, is is an absolute CUTTHROAT environment right now.
You need to be prepared by that by being VERY careful about the impact of the projects you pick, the quality of your faculty mentor, etc. Getting a PhD in 3 years studying a viral disease in chickens and having publications in JAVMA, versus getting a PhD in 5 years in human disease/animal models of human disease and having publications in things like the Journal of Immunology? The second person will be chosen pretty much every time for a research/tenure-track faculty position.