He used international dollars, which might be precisely what you’re looking for, in his last article (https://ourworldindata.org/extreme-poverty-in-brief https:

He used international dollars, which might be precisely what you’re looking for, in his last article (https://ourworldindata.org/extreme-poverty-in-brief https://ourworldindata.org/extreme-poverty-in-brief) it is unclear if he used the same metric or not this time but I’d be very surprised if he didn’t, specially considering he references his old article several times.