News: Housing instability diagnostic codes exhibit poor performance, case study shows
ICD-10 diagnostic codes are highly inaccurate for identifying and capturing housing instability, a new case study published in JAMA Network Open suggests.
The recently released report examined 14,562 patients enrolled in a Chicago-based housing program. According to its authors, the report “sought to evaluate the performance of Z59 codes for identifying housing instability during health care encounters using patient-reported data on housing instability as the reference standard to define this exposure.”
Of note, earlier this month, CMS granted CC status to the codes describing housing instability found in category Z59 in the fiscal year (FY) 2025 Inpatient Prospective Payment System (IPPS) final rule, which will impact payments for discharges beginning on October 1, 2024.
The study broke down the identification of housing instability into four components:
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Group A (“proportion of patients experiencing housing instability who had a Z59 code”)
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Group B (“proportion not experiencing housing instability who did not have a Z59 code”)
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Group C (“proportion without a Z59 code who were experiencing housing instability”)
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Group D (“proportion without a Z59 code who were not experiencing housing instability”)
According to the results of the report, 28.0% of respondents were in group A, 0.5% of respondents were in group B, 71.2% of respondents were in group C, and 0.2% of respondents were in group D.
“To our knowledge,” the authors concluded, “this is the first study examining the performance of Z59 codes that used patient-reported data as the reference standard to define housing instability. We found that Z59 codes exhibited poor overall performance, as evidenced by their low sensitivity and specificity.”
Editor’s note: To read the JAMA Open Network article, click here. To read about the changes included in the FY 2025 IPPS final rule, click here.