Observational studyKidney3602026
Clinical Relevance of Calcium Measures: QT-Based Comparison of Ionized, Total, and Albumin-Corrected Calcium.
Observational study in Kidney360, 2026. The graph could read no effect estimate from its abstract, so it casts no vote on the map. Not yet cited in PubMed.
What it found
Each row is one number read from the abstract, on the scale the paper reported it, with its interval. Left of the dashed line favours the treatment, right favours the comparator. Under each row is the sentence it came from. New to these charts? A ten-minute tutorial.
The abstract states no effect estimate the extractor could read, or names no intervention and outcome on the map, so this paper lights no cell and moves no belief. It is still indexed, cited and linked below.
The trial behind it
Trials whose registry record cites this paper, or whose number appears in the abstract. A trial that started after this paper was published is citing it as background, not reporting it.
Neither the registry nor the abstract names a trial number. If this is a trial report, that itself is worth knowing.
Who cites it
0 citing papers in PubMed.
No citing paper in PubMed yet.
Corrections and comments
PubMed lists nothing against this paper. Absence here is not a guarantee, only a check that was made.
Authors and funding
4 authors.
Funding
No grant is acknowledged in the PubMed record.
Abstract
key pointsIonized calcium showed the strongest associations with the QT interval, whereas total and corrected calcium showed weaker associations. Calcium measures that correlated better with ionized calcium did not necessarily perform better for QT-based outcomes. These findings reinforced ionized calcium as the most clinically valid reference and supported outcome-based calcium assessment.
backgroundIonized calcium (iCa) is the physiologically active fraction of circulating calcium, whereas total calcium (tCa) and albumin-corrected calcium (cCa) remain widely used. Despite growing concerns over the accuracy of correction formulas, most evaluations rely on concordance with iCa rather than meaningful physiologic outcomes. We compared iCa, tCa, and cCa and assessed their clinical validity using ventricular repolarization-reflected by the QT interval-as a physiologic end point.
methodsThis single-center cross-sectional observational study included adults who visited our outpatient department with simultaneous measurements of iCa, tCa, electrolytes, albumin, and electrocardiography. iCa, tCa, and seven albumin-correction formulas were examined. Associations with the QT interval were evaluated using linear regression and restricted cubic splines; logistic regression assessed corrected QT prolongation. Sensitivity analyses included alternative QT-correction methods and analyses in hypoalbuminemia.
resultsAmong 647 participants (median age 68 years; 54% male), common comorbidities included hypertension (33%), diabetes (18%), and cardiac disease (11%). Correlations between iCa and other calcium measures varied widely. In fully adjusted analyses, iCa demonstrated the strongest association with QT interval (standardized β =-0.22; 95% confidence interval, -0.29 to -0.14). tCa and all cCa exhibited substantially weaker associations. Although some tCa and cCa demonstrated relatively higher correlation with iCa, they exhibited weaker associations with QT. In hypoalbuminemia (albumin <3.0 g/dl, n =118), agreement with iCa declined for all cCa, and associations with QT were attenuated; only iCa (standardized β =-0.25; 95% confidence interval, -0.44 to -0.06) and limited formulas (notably Payne) retained modest associations.
conclusionsiCa is the physiologically and clinically valid measure of calcium status consistently demonstrating the strongest associations with ventricular repolarization. By contrast, tCa and cCa demonstrate substantially reduced clinical relevance and numerical concordance with iCa does not reflect clinical validity. These findings support outcome-based validation of calcium measure and reinforce the importance of direct iCa measurement.
Indexed as
Identifiers
What OpenQuestion holds
Registered trials
Read under generation 80e0d062 · epoch 390. Bibliography from PubMed, PubMed Central and OpenAlex; grants from NIH RePORTER; trial links from ClinicalTrials.gov; estimates, votes and beliefs from the OpenQuestion graph.