While scrolling through today's newsfeed, I came across this blog article from MedPage Today about the use of something call surrogate endpoints: (Link). In turn, this article had links to another excellent posting on what a surrogate endpoint is: Primer on Surrogate Endpoints.
For those of you who are still feeling a bit woozy after reading the medical jargon, let me use this metaphor: think about surrogate endpoints as kind of like the grading system that is used in schools. Teachers/parents/children traditionally have used the grading system as an indicator of how the child is doing in skill now, but they also look at these grades as indicator of how well the child is going to do in their future academic career and there is always speculation about how they are going to do well in life. But, those grades are just one indicator of success later. Teachers and parents also look at the child's interpersonal skills, what kind of help/support they are getting in the home to achieve those grades, what kind of physical limitations they might have, what kind of learning difficulties they might have, etc to paint the whole picture. People with diabetes and/or high cholesterol also get "report cards" that reflect their latest blood cholesterol and triglyceride levels, their Hemoglobin A1C test, and quite often their weight/BMI (seriously, several of the educators I've worked with call them report cards) as some sort of indicator of how they are doing with current disease control and speculation of future health and longevity.
And what I just mentioned was the positive side of the metaphor in an idealized school situation (I'm also thinking of what school was like more years ago than I'm admitting), let's look at the downside of the metaphor. How many teachers/parents/children do we know that are so obsessed with getting a good grade in a particular subject or subjects that they actually neglect learning other life skills? Or how many kids worked their behinds off to get a passable grade and were told they weren't working hard enough? And how many kids to we know who didn't do well because of lack of parental support or poor nutrition? And how many kids do you know who did well academically but didn't do well later in life for whatever reason? The parallel that I am trying to draw here is that some people are so focused on getting that cholesterol down that they are willing to put up with medication side effects instead of focusing on diet. I have seen so many people work to get their A1C down to goal but their docs tell them it's not good enough. Or they have a doc that is unaware that BMI should not be used to judge individuals. Or, they have limited funds and social support making achieving their health goals difficult. In other words, because your health "report card" was off your are "told off" by your doc or somehow made to feel like a moral failure when that is only the tiniest part of the picture. So what does a health conscious skeptic do?
1) As I've said before, read the original research associated with the "medical breakthrough of the week" as much as you can.
2) Understand that your cholesterol levels, etc are just one indicator of your overall health. While usually much more scientific than a crystal ball in judging future outcomes, they are not going to tell you "you will have a heart attack on such and such a date."
3) Find out what is really a good marker for your age group based on the available research. For example, if I have a patient over 75 years of age and has cognitive deficits, their goal is usually to achieve an A1C of less than 8%. We don't want their blood glucose levels to drop too low as they may not be able to communicate the problem and we are not worried about complications long term. If they are 29 years of age and they want to have better odds at keeping their kidneys in good shape, we would set the goal of <6.5%. Remember, the medical breakthrough of the week might not even apply to you!
4) Get a complete picture as much as possible. Is your bad cholesterol high? OK, find out about particle size and inflammatory markers (CRP levels). Told you are too fat? Remind your doc you lost a hundred pounds and you have kept it off for a year.
5) If you are unhappy with what your doctor/diabetes educator/dietitian is telling you in regards to your indicators, something doesn't make sense, or you feel that a particular goal is not achievable, then you can politely tell him/her what the problem is. For example, if you go for your physical and find out your "bad" cholesterol is high and your doc wants to put you on medicine right away, tell him/her that you want to come back in 3 months at the latest as you want more time to research the side effects/risks of that medicine and you want to improve your diet (and be specific!). If your doc is not willing to work with you, find another doc.
Take home message—Surrogate endpoints are great for stimulating research to help find ways to help us live healthier and maybe longer. Stop calling your labs a report card and look at the big picture.