Re: Multiple race coding
Dear Paul Hutson,
I believe a review of how Warfarin dosing algorithms dealt with multiracial
subgroups can help you (Asiimwe IG, Zhang EJ, Osanlou R, Jorgensen AL,
Pirmohamed M. Warfarin dosing algorithms: A systematic review. Br J Clin
Pharmacol. 2021; 87: 1717–1729. https://doi.org/10.1111/bcp.14608).
Please check the supplementary materials for a compilation of dosing algorithms.
The IWPC 2009 dosing algorithm was:
√dose (mg/wk) = 5.6044 – 0.2614 (age) + 0.0087 (height) + 0.0128 (weight) –
0.8677 (VKORC1 AG) – 1.6974 (VKORC1 AA) – 0.4854 (VKORC1 unknown) – 0.5211
(CYP2C9*1*2) – 0.9357 (CYP2C9 *1*3) – 1.0616 (CYP2C9*2*2) – 1.9206 (CYP2C9*2*3)
– 2.3312 (CYP2C9*3*3) – 0.2188 (CYP2C9 unknown) – 0.1092 (Asian) – 0.2760
(Black) – 0.1032 (Mixed/Missing race) + 1.1816 (enzyme inducer) – 0.5503 (amio)
The algorithm by Bosch 2014 was:
Ln dose (mg/d) = 2.20 – 0.0106 (age) + 0.122 (BSA) – 0.190 (CYP2C9 variant
alleles) – 0.229 (VKORC1 AA) – 0.636 (VKORC1 GA) – 0.0742 (Taino) – 0.118
(African) – 0.120 (Mixed) + 0.216 (target INR) – 0.0448 (statin) – 0.233 (amio)
–0.126 (smoker) + 0.135 (DM) + 0.09837 (vit K)
You can see some algorithms used "Mixed/Missing Race" or "Mixed".
However, since this is just merging highly heterogenous subgroups into one
group, I don't think it is ideal way to do covariate modeling.
Perhaps it would be better to divide each specific multiracial group (ex.
Black/White/Asian/Multiracial1(Black&White)/Multiracial2(Black&Asian)/Multiracial3(White&Asian)/Multiracial4(Black&White&Asian)
Then, when the covariate effects for these groups cannot be estimated precisely
(ex. RSE >= 50%) or there is no advantage in including the covariate effects
for specific groups (ex. by Likelihood Ratio Test), the covariate effects for
these groups can be fixed to 0, so that the parameters are the same as the
reference race.
Sincerely,
Jun Seok Cha
Quoted reply history
________________________________
보낸 사람: [email protected] <[email protected]> 님이 Leonid
Gibiansky <[email protected]> 님을 대시하여 보냄
보냄: 화요일, 12월 9, 2025 5:32:06 오전
받는 사람: Paul Hutson <[email protected]>; Nmusers <[email protected]>
제목: Re: [NMusers] Multiple race coding
I've seen it coded as "Multiple" category, and used similar to "Other"
(i.e., not very helpful)
On 12/8/2025 10:39 AM, Paul Hutson wrote:
> I’ve got a study in which subjects have the option of identifying as
> belonging to more than one race.
>
> How are others in this group:
>
> 1. Coding this in their data file
> 2. Incorporating this as a possible covariate in their PopPK model?
>
> Thanks!
> Paul
>
> Paul R. Hutson, PharmD, BCOP
>
> Distinguished Professor (CHS)
>
> Thora M. Vervoren Professor for Research in Psychoactive Substances
> UW School of Pharmacy
>
> Director, UW Madison Transdisciplinary Center for Research in
> Psychoactive Substances https://www.research.pharmacy.wisc.edu/tcrps
>
> Faculty Leader, Paul P. Carbone Comprehensive Cancer Center Cancer
> Pharmacology Laboratory https://cancer.wisc.edu/research/resources/ddc/
cancer-pharmacology/>
>
> T: 608.263.2496
>
> [email protected]
>
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