Effect of number of replicate electrocardiograms recorded at each time point in a thorough QT study on sample size and study cost
Abstract
In a "thorough QT/QTc" (TQT) study, several replicate electrocardiograms (ECGs) are recorded at each time point to reduce within-subject variability. This decreases the sample size but increases the cost of ECG analysis. To determine the most cost-effective number of ECG replicates, the authors retrospectively analyzed data from the placebo and moxifloxacin arms of a TQT study with crossover design. Six replicate ECGs were recorded at 7 time points on day -1 (baseline day), day 1, and day 3 in 124 normal healthy volunteers who were randomized to receive moxifloxacin or placebo on day 1 and the other treatment on day 3. QT interval was corrected for heart rate by the Fridericia (QTcF) and individual subject-specific (QTcI) formulas. Within-subject and between-subject standard deviations for QTcF obtained by repeated-measures analysis of covariance were 9.5 and 13.3 milliseconds with 1 replicate; 7.8 and 12.7 milliseconds with 2 replicates; 7.3 and 12.3 milliseconds with 3 replicates; 6.9 and 12.2 milliseconds with 4 replicates; 6.8 and 11.9 milliseconds with 5 replicates; and 6.6 and 11.8 milliseconds with 6 replicates. Within- and between-subject variance with QTcI also declined with increasing replicates. Sample size benefit based on these estimates was negligible beyond 4 replicates. The study cost was least with 3 or 4 replicates, depending on per-ECG and per-subject costs.
How strong is the evidence?
Evidence Hub reads this as a randomized trial, done in people. Its evidence level is 2 of 5 (High · randomized trial). Randomized trials of a reasonable size are the strongest single-study design. Reported size: 124 participants or records.
Read the paper
Related studies
- Synthesis, In Vitro and In Silico Molecular Docking Studies of Novel Phthalimide–Pyrimidine Hybrid Analogues to Thalidomide as Potent Antitubercular Agents
- Exploring the inhibitory performance of expired moxifloxacin and norfloxacin on copper corrosion in saline environment
- Molecular investigation of antimicrobial peptides against Helicobacter pylori proteins using a peptide-protein docking approach
- Screening of novel narrow-spectrum benzofuroxan derivatives for the treatment of multidrug-resistant tuberculosis through in silico, in vitro, and in vivo approaches
- Synthesis, Characterization, Anticancer, Antioxidant, and In Silico Evaluation of Semicarbazides and Thiosemicarbazides
- Fast and accurate prediction of drug induced proarrhythmic risk with sex specific cardiac emulators
Go deeper in Evidence Hub
Evidence Hub adds a study data sheet (design, sample size, evidence level, key numbers), an AI summary and a chat grounded in the paper's text.