Last week, when I was double-checking the ICD code for XLH, I found out (a couple years after it happened) that there is a whole new ICD billing code (ICD-11) that’s been adopted, and it has done a really terrible thing for classification of XLH.
In the previous code (ICD 10), XLH was classified with other endocrine conditions, under the general heading of hypophosphatemia. Which is where it should be. Now, to my total horror (and yours too, I hope, since you know how I feel about calling XLH a form of rickets), it’s listed as “hypophosphatemic rickets,” and it’s under the general heading of “disorders of vitamin D metabolism or transport.”
It’s bad enough that they’re reinforcing the idea that the disorder is primarily pediatric, but the general classification is just flat-out wrong. We do have trouble processing vitamin D into calcitriol, but that’s NOT the key to the disorder. The key is phosphate wasting. XLH belongs with the other phosphate-wasting conditions, not the vitamin D ones.
If you type “x linked hypophosphatemia” into the ICD-11’s search box, you get sent to “hypophosphatemic rickets (5C63.22).” Which, no. Just no.
Oddly, if you just type “hypophosphatemia” into the ICD-11’s search box, you get two options: the horrifically misnamed “hyopophosphatemic rickets,” plus the more appropriate name, “familial hypophosphatemia” (GB90.48). Just to add to the confusion, the subheading under hypophosphatemic rickets is “autosomal recessive hypophosphatemia,” which is ultra-rare, rather than the most common genetic hypophosphatemia, XLH. And it’s not even alphabetical, because “autosomal dominant hypophosphatemia comes after “autosomal recessive.”
I’d like to think that expert clinicians will choose the more correct code for “familial hypophosphatemia.” It’s in the right category, at least: “conditions in which renal excretion of calcium and/or phosphorus is deranged.” (Gotta love the “deranged” here.) But what’s weird is that it doesn’t list either XLH or the autosomals under this heading, so what on earth could it be referring to? And it’s under the heading of kidney disorders, when it’s not really the kidney that’s the problem, but the endocrine system.
Bottom line: XLH should really be classified as an endocrine disorder, like it was in ICD-10.
For now though, we’ll have to muddle along with the errors in terminology and classificatio and advocate for correcting them in the next iteration. Perhaps we’ll be able to get it fixed by showing how the ICD-11 has introduced confusion to the coding of the genetic hypophosphatemias, when the whole point of classification systems is consistency. With the current system, some coders will use the “familial hypophosphatemia” code and others will use the rickets code. I guess we’ll be able to see which coders understand the condition and which don’t, based on which one they choose! Or maybe adults will be listed under one and kids under the other. Yeah, that’ll help patients get whole-body/whole-life/whole-family care.
As an aside, it’s even harder to find the ICD-11 code for TIO. The search engine doesn’t recognize either Tumor-induced osteomalacia or oncogenic osteomalacia, the most common terms for it. According to Orphanet, it’s classified as FB80.Y, for “other specified disorders of bone density and structure.” Yeah, that’s going to be easy for clinicians to find and use consistently.
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Please note that the author is a well-read patient, not a doctor, and is not offering medical or legal advice.
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