@francolepza No, of course! Super fair question with many answers. Let me start this by mentioning that this is from experience I've had working with and learning from many different doctors from all specialties in both inpatient and outpatient settings. All of this is based on anecdotal experience.
1- They are physicians who are not specialized in endo/nephro and they simply do not know. Vit D is slightly less straightforward than other vitamins (I don't think the mechanism of action was fully elucidated until the 70s). Unless you are in a field that deals with it daily, odds are, you probably forgot it. A PCP has SO many things they need to worry about, so clinical findings of actual importance that they need to look out for with outrageously limited time that Vit D isn't exacly on the top of their list of to-dos. While ideally, guidelines will be followed by all physicians, I can't imagine PCPs taking time out of their busy days to look up the testing guidelines for vitamin D, especially since it is of so little significance on the grand scheme of things (compared to heart disease, diabetes, obesity......). With the growing popularity of vit D testing (see the Nature link from my previous comment), people are coming in all the time asking for vitamin D testing despite the lack of evidence. Looking up the clinical relevance of the test and then telling the patient no will not only make the patient upset, but on the grand scheme of things, doesn't matter that much. While I personally disagree and think that we should do a better job of regulating Vit D testing (it's a waste of money/resources and causes needless anxiety), I can certainly understand the barriers in educating and implementing this. I've also seen neurologists prescribe vitamin D to patients. When I asked one of them what her clinical indication for checking and prescribing it was, she basically said "Everyone does it, so why not?" That, believe it or not, is not how tests should be ordered or how medicine should be practiced. A test should only be ordered to confirm a strong clinical suspicion (unless there is sufficient clinical evidence that a screening test is beneficial in a certain population). Tests should not be ordered for shits and giggles cause I have nothing else to do.
2- This is slightly more nihilistic, but I've talked to a few physicians about this. After appropriate workup, if disease is ruled out, most people don't like hearing "well, just feel better. there's nothing medically wrong with you." So, a lot of physicians have started to use Vitamin D levels as sort of a scapegoat. You tell someone that there is something wrong with them and a magical pill will fix it. Because of the placebo effect (HUGE fan of this), people take the vitamin and report feeling better. Makes the patient happy and makes the doc's life a little easier. I've seen vitamin D used like this in several circumstances. I'd question the doctor and ask why they prescribed vitamin D for something that the patient complained about completely unrelated to vitamin D, and that was more or less what I was told. Not ideal, but given that vit D causes no real harm unless taken in massive quantities, it is what it is. Doctors are human too.
3- There are many papers arguing for the benefit of vitamin D, but in the opinion of the the JCEM (https://academic.oup.com/jcem/article/96/7/1911/2833671 see recommendation 1.1 and table 2 for the "at risk" population), screening of vitamin D levels on a population scale is NOT recommended as there is no evidence of its benefit. The concept of population screening is difficult to fully rationalize because as humans, we believe much more in cases and examples than we do in evidence based data. Unless studies have been done to show the benefit of screening with a certain test, it should not be done. Throughout my courses, I've had this point hammered in countless times simply because it's a difficulty one to understand and inherently counterintuitive (epidemiologists have mentioned that not enough physicians fully understand this concept, which is why it's important for us as medical students to really learn it). Many practicing clinicians do not keep up to date on these things, especially if it is not within their field. By not knowing this, I'm in by no means saying a doctor is a bad doctor you shouldn't trust; I'm simply saying it's out of their expertise, but since it seems like such a basic concept with minimal consequences, they get involved regardless. There are many more important things to being a good doctor.
Sorry about this novel hahah. I hope this somewhat answered your question? If you want to read the guidelines straight from the horse's mouth, look at the JCEM recommendations. Just because the guidelines are out there, though, doesn't mean that everyone will follow them.
1- They are physicians who are not specialized in endo/nephro and they simply do not know. Vit D is slightly less straightforward than other vitamins (I don't think the mechanism of action was fully elucidated until the 70s). Unless you are in a field that deals with it daily, odds are, you probably forgot it. A PCP has SO many things they need to worry about, so clinical findings of actual importance that they need to look out for with outrageously limited time that Vit D isn't exacly on the top of their list of to-dos. While ideally, guidelines will be followed by all physicians, I can't imagine PCPs taking time out of their busy days to look up the testing guidelines for vitamin D, especially since it is of so little significance on the grand scheme of things (compared to heart disease, diabetes, obesity......). With the growing popularity of vit D testing (see the Nature link from my previous comment), people are coming in all the time asking for vitamin D testing despite the lack of evidence. Looking up the clinical relevance of the test and then telling the patient no will not only make the patient upset, but on the grand scheme of things, doesn't matter that much. While I personally disagree and think that we should do a better job of regulating Vit D testing (it's a waste of money/resources and causes needless anxiety), I can certainly understand the barriers in educating and implementing this. I've also seen neurologists prescribe vitamin D to patients. When I asked one of them what her clinical indication for checking and prescribing it was, she basically said "Everyone does it, so why not?" That, believe it or not, is not how tests should be ordered or how medicine should be practiced. A test should only be ordered to confirm a strong clinical suspicion (unless there is sufficient clinical evidence that a screening test is beneficial in a certain population). Tests should not be ordered for shits and giggles cause I have nothing else to do.
2- This is slightly more nihilistic, but I've talked to a few physicians about this. After appropriate workup, if disease is ruled out, most people don't like hearing "well, just feel better. there's nothing medically wrong with you." So, a lot of physicians have started to use Vitamin D levels as sort of a scapegoat. You tell someone that there is something wrong with them and a magical pill will fix it. Because of the placebo effect (HUGE fan of this), people take the vitamin and report feeling better. Makes the patient happy and makes the doc's life a little easier. I've seen vitamin D used like this in several circumstances. I'd question the doctor and ask why they prescribed vitamin D for something that the patient complained about completely unrelated to vitamin D, and that was more or less what I was told. Not ideal, but given that vit D causes no real harm unless taken in massive quantities, it is what it is. Doctors are human too.
3- There are many papers arguing for the benefit of vitamin D, but in the opinion of the the JCEM (https://academic.oup.com/jcem/article/96/7/1911/2833671 see recommendation 1.1 and table 2 for the "at risk" population), screening of vitamin D levels on a population scale is NOT recommended as there is no evidence of its benefit. The concept of population screening is difficult to fully rationalize because as humans, we believe much more in cases and examples than we do in evidence based data. Unless studies have been done to show the benefit of screening with a certain test, it should not be done. Throughout my courses, I've had this point hammered in countless times simply because it's a difficulty one to understand and inherently counterintuitive (epidemiologists have mentioned that not enough physicians fully understand this concept, which is why it's important for us as medical students to really learn it). Many practicing clinicians do not keep up to date on these things, especially if it is not within their field. By not knowing this, I'm in by no means saying a doctor is a bad doctor you shouldn't trust; I'm simply saying it's out of their expertise, but since it seems like such a basic concept with minimal consequences, they get involved regardless. There are many more important things to being a good doctor.
Sorry about this novel hahah. I hope this somewhat answered your question? If you want to read the guidelines straight from the horse's mouth, look at the JCEM recommendations. Just because the guidelines are out there, though, doesn't mean that everyone will follow them.
