A (9:32)
We will now jump into the methodology and as mentioned earlier, you get a two for one on this one. So the authors here combine two different studies in this paper and they've labeled them Study 1 and Study 2 to help us keep track of them. And Study 1 is a retrospective cohort study, and then Study 2 is a clinical trial. So we'll talk about those methodologies, contrast them just a little bit here before we dive into the specifics of these two studies. As a reminder, retrospective cohort studies, the way those work is you have at least two different groups, and it's two here. And those groups are defined based on an exposure. It can be a little bit hard to think about it in intervention studies like this, or meaning where the exposure is an intervention. And here it's going to be a surgical intervention that we're going to be talking about. So that's the exposure. So all of these individuals have MAX meet criteria for that. And then they're split into groups based on whether they had a surgery or did not have a surgery. They're then followed over time. That's the key aspect of a cohort study. And one, I think, really important thing to keep in mind with, with this is with all cohort studies, is that assignment to be in the exposed group or the unexposed group, that's not a random assignment. So there's something driving that. And it may be clinicians who are determining that it may be patients. And this is just a part of usual clinical care. These things are appropriate. It is challenging, though, when we turn these into studies and we try to investigate differences, because we often don't know what's driving that decision to have a surgery or to not have a surgery or whatever else the exposure might be. So we're going to have to keep that in mind. The benefit of a clinical trial, so that's the second study here, is that it helps with a lot of these issues and in particular, when it is a randomized clinical trial, then that decision of whether you're going to be exposed or not exposed, that is not based on somebody making a decision. It's based on a random allocation that helps. In particular with confounders, it's not that it gets rid of confounders that could be driving the outcome. The idea is if you've done your randomization correctly, it's. It balances them out. And so in a way of speaking, they're going to cancel each other out. Now, one key caveat to that is that assumes that after you've done your randomization, that you're able to maintain all of those subjects, or at least most of those subjects in both of those groups, and then that you analyze them as they were randomized. That's that intention to treat analysis. We're going to have to think about that carefully here. Another thing that I think we also want to keep in mind as we look at these studies is often, we assume with clinical trials is that they're placebo control, that that's often a fe, particularly with medications, that is very difficult to do. As I'm sure you can imagine with surgical studies, it's not impossible. There are clinical trials that sham surgeries are used. But again, as you can probably imagine, that is not an easy thing to pull off. And so whenever you don't have that, that sets up yourself for some other biases that you have to keep in mind. So we're going to think about those as well. Okay, now long enough, we're going to dive into these studies in particular. So study one, again, that's that retrospective cohort study. This came from two different centers in Italy and looked at dates from January 2008 through June 2013. And initially, so Jill walked us through, there are evolving criteria. So initially this cohort was formed based on older criteria for whether they would recommend surgery in patients with adrenal incidentalomas. So to give you an overview of those. So if you had a deck suppression test, the cortisol level that was greater than five, that was a reason to intervene surgically. There was also another criteria where it could be one of the as two out of three things. So if your cortisol after deck suppression was greater than 3, had an ACTH less than 10, or urine free cortisol that was greater than 70, again, any two of those three that met criteria. So in this original cohort, there were 605 patients with adrenal incidentalomas, and then 55 of them met criteria and had surgery recommended. The authors went back and looked at this cohort and then applied these newer criteria to that. And with that, most of those patients still met criteria. It was 53, so two of them didn't. But 53 met criteria. And when they looked at what happened to those individuals, 31 of them underwent surgery and 22 opted for conservative treatment. Here, this is where we've got to think about that. It's a selection bias. In particular, we don't have a great understanding of why most of those patients decided to undergo surgery, but a significant number elected for conservative treatment. And you do have to worry that, well, whatever was driving that decision, maybe that's going to be what drives the outcome of interest, which to skip ahead and you can already guess, is going to be vertebral fractures. We're going to keep that in mind. Now, the authors recognize this. They do a good job of describing the inherent issues, the limitations of observational studies, and that's why they wanted to couple their investigation with a clinical trial. So this is study two. This was a randomized clinical trial, and the dates from that were September of 2016 through February 2020. The inclusion criteria for this is that you had to have a unilateral adrenal incidentaloma that was greater than a centimeter in diameter and the CT scan to be consistent with it being adenoma. And they were looking at individuals ages 40 to 75. There were several important exclusion criteria. So, as Oksana mentioned, we don't think about max if somebody has obvious Cushing's syndrome. So having signs or symptoms of hypercortisolism was an exclusion criteria here. If you had a large tumor, so if your adrenal insuloma was greater than 5, or if the imaging characteristics were not suggestive of an adenoma, that was an exclusion criteria. If you had biochemical evidence of either a pheo or primary aldo, that was also exclusion criteria. If you were missing data, and then also they listed if you had interfering drugs or medical conditions well known to affect bone health, all of those were removed from the study here. So with that, after they excluded all those individuals, they were left with 71 eligible subjects. 62 of them agreed to participate in that. So at that point, they did their randomization. So 62 individuals randomized. They got two equal groups of 31 in each.