Secondary analysis
Effects of Atrial Fibrillation Screening According to N-Terminal Pro-B-Type Natriuretic Peptide: A Secondary Analysis of the Randomized LOOP Study
- Secondary analysis of the LOOP randomised trial
- post hoc analysis
- 1:3 randomisation
Authors' conclusion
In an older population with additional stroke risk factors, ILR screening for AF was associated with a significant reduction in stroke risk among individuals with higher NT-proBNP levels but not among those with lower levels.
Study context
- Population
- Atrial fibrillation (AF)-naïve individuals ≥70 years with additional stroke risk factors and baseline NT-proBNP available96.9% of trial population
- Participants
- 5,819 individuals
- Comparison
- Implantable loop recorder (ILR) screening vs usual care, by baseline NT-proBNP
- Primary endpoint
- Screening efficacy (AF yield and stroke prevention) by NT-proBNP
Primary result
As reported in the abstract
Stroke/SE and stroke/SE/CV death, ILR vs control, by NT-proBNP subgroup
ILR vs ControlHazard ratio (95% CI)
stroke/SE, NT-proBNP above median; Pinteraction=0.029
0.60(0.40–0.90)
stroke/SE/CV death, NT-proBNP above median; Pinteraction=0.045
0.70(0.53–0.94)
Further findings
| Outcome | HR (95% CI) | |
|---|---|---|
| AF diagnosis, NT-proBNP above vs below median — NT-proBNP above median vs NT-proBNP below median · ILR | 1.84 (1.51–2.25) | |
| AF diagnosis, NT-proBNP above vs below median — NT-proBNP above median vs NT-proBNP below median · Control | 2.79 (2.30–3.40) | |
| Clinical events, NT-proBNP above vs below median — NT-proBNP above median vs NT-proBNP below median · stroke or SE | 1.21 (0.96–1.54) | |
| Clinical events, NT-proBNP above vs below median — NT-proBNP above median vs NT-proBNP below median · stroke/SE/CV death | 1.60 (1.32–1.95) | |
| Clinical events, NT-proBNP above vs below median — NT-proBNP above median vs NT-proBNP below median · all-cause death | 1.91 (1.61–2.26) | |
| 0.20.5125Hazard ratio (log scale) |
All-cause death, ILR vs Control, by NT-proBNP subgroup
- No risk reduction in either NT-proBNP subgroup
- interaction P=0.68
NT-proBNP as a continuous variable
- Similar findings
Original publication
Effects of Atrial Fibrillation Screening According to N-Terminal Pro-B-Type Natriuretic Peptide: A Secondary Analysis of the Randomized LOOP Study. Circulation. Published 15 April 2023. doi:10.1161/circulationaha.123.064361
Summarised from the published abstract; every number is checked against it