Incremental Value of NT-proBNP Over HCM-AF Score in Risk Stratification for Atrial Fibrillation in Patients With Hypertrophic Cardiomyopathy.

AF occurred in 8.4% of HCM patients over a mean follow-up of 3.4 years.

• 778 HCM patients were included in this retrospective cohort study.
• 65 patients (8.4%) developed new-onset AF during follow-up.
• Mean follow-up duration was 3.4 ± 2.3 years.

The HCM-AF score stratified AF incidence rates significantly across low, intermediate, and high risk groups.

• Incidence rate of AF per 1000 person-years for the low HCM-AF score group was 8.7 (95% CI: 3.5–17.7).
• Incidence rate for the intermediate HCM-AF score group was 18.0 (95% CI: 7.7–48.8).
• Incidence rate for the high HCM-AF score group was 59.6 (95% CI: 27.1–157.1), significantly higher than the other groups.
• The HCM-AF score was described as "reliable and robust for Asian HCM patients."

A NT-proBNP cut-off value of 240 pg/mL was identified via spline curve analysis to stratify AF risk.

• Spline curve analysis was used to determine the cut-off value.
• The cut-off was established at 240 pg/mL.
• Incidence rate of AF per 1000 person-years for the low NT-proBNP group (< 240 pg/mL) was 9.2 (95% CI: 4.6–16.1).
• Incidence rate for the high NT-proBNP group (≥ 240 pg/mL) was 38.1 (95% CI: 20.3–79.4).

High HCM-AF score and high NT-proBNP were independent predictors of new-onset AF.

• High HCM-AF score was an independent predictor with HR: 3.55 (95% CI: 1.33–9.48; p = 0.011).
• High NT-proBNP (≥ 240 pg/mL) was an independent predictor with HR: 2.49 (95% CI: 1.21–5.10; p = 0.013).
• Both variables remained significant after multivariable adjustment.

Adding NT-proBNP to HCM-AF score-based models improved discriminative ability and model fit.

• Harrell's C-index increased from 0.709 to 0.768 with the addition of NT-proBNP to the HCM-AF score model.
• The likelihood ratio increased from 33.15 to 51.02 when NT-proBNP was added.
• Both Harrell's C-index and likelihood ratio test were used to evaluate incremental value.