Tag Archives: BMI

Resources for Fat People Looking for Total Joint Replacement Surgery

We support a ceasefire in Palestine.

stylized picture of an x-ray in dark blue, with one hip and both knees showing red for pain and inflammation

Debbie says:

A fat person who needs a total joint replacement of their hips and/or their knees can run into an almost impenetrable wall of rejection. Many if not most doctors who perform these surgeries believe the common wisdom that outcomes of these surgeries are affected by the patient’s body mass index (BMI) to the point where many of them simply turn patients away out of hand.

(TL;DR: if you are looking for medical evidence to share with potential surgeons on why they might be wrong, I’ve collected some here and it’s available for you to use. It’s also available for you to add to, so it can be more useful to the next person. Just leave comments with links, and I’ll incorporate the new information. All details and links to the studies listed below are available at the link. Pointers to surgeons who are open to working with fat people also very welcome.)

To begin with, BMI is arrant nonsense; all it is is the ratio of your weight to the square of your height. I wrote about it here in 2007 and nothing about its history (invented by a statistician with no medical training), its uselessness, or its general acceptance by the medical profession has changed in 17 years. I call it “braindead, meaningless, insidious.”

But here we are, being forced to deal with it as if it was real.

I’ve known about the problem with obtaining joint replacement surgery for a long time, but recently a close friend of mine has been going through it, and it made me really angry. It’s especially frustrating because she is very close to the same weight she was in 2017 when she had a successful replacement on the other knee, and now the surgeon who did that one, and several other surgeons, have turned her away without a word of compassion or empathy. “Lose weight and come back,” they say, often that bluntly.

So I decided to do some research. And sure, there’s a lot of research that says BMI increases risk of surgical complications, particularly infection immediately after surgery. But there’s also substantial evidence that this is not necessarily true–my personal guess is that many of the studies that show additional risk are flawed by an implicit bias against doing anything medical to help a fat person until/unless they lose weight.

Some examples from the research linked above:

In a study of 2,040 patients, published in the Journal of Bone and Joint Surgery, July 19, 2017:

 A greater obesity level was associated with more pain at baseline but greater postoperative pain relief, so the average postoperative pain scores did not differ significantly according to BMI status. Patients undergoing TKR had an average age of 69 years; 61% were women, 93% were white, and 25% were severely or morbidly obese. A greater obesity level was associated with a lower PCS score at baseline and 6 months. The postoperative gain in PCS score did not differ by BMI level. A greater obesity level was associated with worse pain at baseline but greater pain relief at 6 months, so the average pain scores at 6 month were similar across the BMI levels.”

In a comprehensive literature review, plus interviews with leading surgeons, published in Arthroplast Today in October 2022:

Importantly, as obese patients have been demonstrated to have equal or greater gains in functional outcomes and quality of life metrics, it is important for obese patients to have access to TJA.

This paper is especially interesting, as it breaks down the factors a surgeon can/should consider in making this decision, taking the conversation away from the rigidity of BMI into a serious examination of risks.

Because so much of the conventional wisdom is some 2020s version of “just lose weight and come back,” I tried to put my finger on truly good studies about the difficulty of losing weight; however, the amount of noise about this, even in serious medical papers, made it almost impossible to evaluate. So the document above closes with information from a careful examination of factors that keep people from losing weight, published in the Journal of Health, Population, and Nutrition, March 2, 2024. The authors identify five major categories of complicating factors preventing weight loss (biological, medical, interventional, lifestyle, and environmental), each with 3-6 subcategories. So it might encourage a doctor to think in a more nuanced way.

Oh, and my friend? She found a fairly reasonable surgeon (or at least his physician’s assistant seems reasonable) who treated her like a human being and paid attention to who she actually is. They still want her to lose weight before scheduling the surgery, but it seems like they have some flexibility in their approach and she feels reasonably comfortable working with them. And she’s waiting a few months — in pain — to see if she can meet their criteria.

Me, I think the whole thing is bullshit and anyone who is in severe pain and physical limitation from needing joint replacement should have the risks explained, and get to make a choice. And the surgeons should be interested in long-term outcomes rather than immediate risks. Oh, and we should have a decent humane health-care system in the United States while we’re at it.

Please use the resource linked above if it can help you. Share it widely so we can make it better. And let me know how useful it is or isn’t.

======================

I occasionally post on Mastodon.

Follow Laurie’s Pandemic Shadows photos on Instagram.

======================

Human Body Temperature Varies: Historically, by Age, and Individually

a thermometer for measuring body temperature

Debbie says:

“Normal” is a word that always makes me skeptical: “not normal” so often means “within the range of human variation” or “not like people I know” or “not like adult white men.” I’ve known for a long time that different individuals have different “normal” body temperatures, and there’s nothing magic about 98.6 (or 37 if you use the much more comprehensible Celsius scale).

I didn’t know that the 98.6 number is from the 1850s, and is based on a study of 25,000 people in Leipzig, Germany.

Brian Resnick, writing at Vox last month, reviewed new findings which say that 98.6 is no longer “normal.” Instead,

In a new paper in the journal eLife, from a group of scientists at Stanford University, researchers analyzed three different databases of human body temperature readings, starting with a cohort of Civil War veterans, then to temperatures taken in the 1970s, and ending with data collected between 2007 and 2017.

Overall, the researchers found that men born in the early 1800s had average body temperatures 1.06°F higher than men today. Women born in the 19th century were, on average, 0.57°F warmer than women today.

Data analysis rules out the possibility that it’s just better thermometers. And while there are some theories about what might be causing the change, none have really caught on more than any other.

Resnick uses this study as a jumping-off point to examine variations in body temperature other than the historical:

As it stands, comparing an individual’s body temperature to a single number doesn’t make much sense.

“You can’t say there is a temperature you should be at, because it depends on who you are,” [Stanford researcher Catherine] Ley says.

Women tend to run a little hotter than men, and their body temperature can fluctuate with the menstrual cycle. Age matters too. The older we get, generally, the colder we are.

A 2017 study in BMJ of 35,500 patients found that our average body temperature declines around 0.03°F every decade (maybe due to the loss of fatty tissue under the skin). So it makes sense if Grandpa complains about being cold over time. People with a higher body mass index tend to run hotter than thinner people (as people with a higher body mass are more insulated). Overall, some people may run half a degree hotter or colder than “average” and that’s fine for them.

However, neither Resnick the journalist, nor Ley the researcher, go far enough. Here’s Ley again:

Instead of a set number like 98.6, Ley says it would be better if there were a sliding temperature scale for individuals to figure out what’s normal for their demographic group.

“If I go into the doctor and I’m 30 years old, and I have a BMI of 20, and it’s 2 o’clock in the afternoon, there will be a normal for that series of characteristics,” she says. “It would be so nice if we could boil health down to simple rules, but biology is more complex.”

Wrong! Leaving aside all of the problems with BMI, that’s still an attempt to define “normal” in a way that makes simple individual variations abnormal. There might be a mean, or a median, for that group, but the only possible “normal” of any value would have to be a range — and that range probably wouldn’t look very different from a general human variation range.

Even though this conversation is taking us further away from “one true number,” the article still doesn’t mention that having a fever (i.e., running hot enough for it to be a problem), or having a troublingly low temperature, is very likely to be coupled with other symptoms: am I shivering? am I sweating?

Based on this article, Ley still wants to rely on numbers provided by instruments, sliding scale or not. She wants to be able to say that if you’re not in the center of your group’s statistics you’re not “normal.” While I am interested in these variations over personal time and historical time, I still want to land on a place where “is this temperature abnormal for you at this time in your life?” is the question the doctor wants to answer.