Predicting ionized hypocalcemia: External validation of an ionized calcium prediction model in patients with COVID-19 and renal failure.
Ann Clin Biochem
; 59(2): 110-115, 2022 03.
Article
in English
| MEDLINE | ID: covidwho-1480322
ABSTRACT
BACKGROUND:
Ionized hypocalcemia is common in critically ill patients with COVID-19 and is associated with adverse outcomes. We previously developed a linear model that estimates ionized calcium (ICa) by adjusting total calcium (TCa) for the three components of the anion gap and albumin. On internal validation, it outperformed the popular method that corrects TCa for albumin alone (cTCa) in diagnosing low ICa. In this study, we sought to externally validate our ICa model in hospitalized COVID-19 positive patients.METHODS:
We retrospectively studied all 200 patients with COVID-19 who were admitted to the State University of New York Downstate Medical Center between March 11th and April 30th 2020 and referred to the nephrology service for renal failure, and who had ICa measured on a venous blood gas within 25 min of a comprehensive metabolic panel. We compared the performance of the ICa model and cTCa in diagnosing low ICa by ROC analysis, and also examined the accuracy of the absolute values predicted by the two methods relative to measured ICa.RESULTS:
On ROC analysis, the ICa model was better than cTCa (area under ROC curve 0.872 [0.025] vs. 0.835 [0.028]; p = 0.045). The ICa model estimated ICa accurately, but the cTCa method seemed to overcorrect TCa, as a substantial number of patients with clearly normal cTCa values had low ICa.CONCLUSIONS:
In an external validation cohort, the ICa model estimated ICa accurately and was better than cTCa in the diagnosis of low ICa. This finding can be useful in guiding direct ICa testing.Keywords
Full text:
Available
Collection:
International databases
Database:
MEDLINE
Main subject:
Renal Insufficiency
/
COVID-19
/
Hypocalcemia
Type of study:
Cohort study
/
Diagnostic study
/
Observational study
/
Prognostic study
Limits:
Humans
Language:
English
Journal:
Ann Clin Biochem
Year:
2022
Document Type:
Article
Affiliation country:
00045632211049983
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