Pregnancy-related heart failure outcomes compared with non–pregnancy-related heart failure in a nationwide register study

Background Pregnancy-related heart failure (HF) is a rare but serious condition associated with significant maternal morbidity and mortality. Despite its clinical severity, both short- and long-term outcomes remain insufficiently characterized. In this nationwide registry study we compared outcomes of women with pregnancy-related heart failure and age-matched women with heart failure unrelated to delivery. Method All women aged 18–50 years registered in the National Patient Register (NPR) between 1 January 1997 and 31 December 2022 were eligible. Using the personal identification number (PIN), data were linked to the Swedish Medical Birth Register, the Cause of Death Register, and the Prescribed Drug Register. Women with first-time heart failure or cardiomyopathy occurring 90 days before to 180 days after delivery were identified using ICD-10 codes I50, I42, I43, and O90.3. Each case was matched by age at HF diagnosis to controls, women with HF but without a registered delivery. Results In total there were 2,347,723 deliveries. Of those 420 cases and 420 controls were included. Mean age 33.4±5.6 vs 32.8±5.6 years (p=0.18). Hypertension (11.4% vs 4.8%; p=0.0004), cardiomyopathy (12.1% vs 7.4%; p=0.020), atrial fibrillation (4.5% vs 1.0%; p=0.0015), and psychiatric disorders (30.5% vs 16.9%; p<0.0001) were more common among controls. Use of beta-blockers was similar between groups (8.3% vs 8.8%; p=0.81). Controls more frequently received ACE inhibitors/ARB/ARNI (7.6% vs 1.9%; p=0.0001), MRA (2.6% vs 0.0%; p=0.0008), and diuretics (6.0% vs 0.5%; p<0.0001). Bromocriptine use among cases was 0.2%. Within 3 months, cases more frequently received diuretics (11.7% vs 6.2%; p=0.0074) and bromocriptine (4.3% vs 0.0%; p<0.0001), whereas use of beta-blockers (19.3% vs 14.5%; p=0.08) and ACE/ARB/ARNI (19.8% vs 14.5%; p=0.054) showed borderline differences and MRA and SGLT2i use did not differ. Treatment duration within 3 years was similar for most drug classes, diuretic therapy was shorter among cases (137 vs 252 days; p=0.040). Within 3 years, cases had lower mortality risk compared with controls. The hazard ratio (HR) for all-cause mortality was 0.10 (95% CI 0.04–0.23; p<0.0001), and for cardiovascular mortality 0.08 (95% CI 0.02–0.32; p=0.0004). Cases had a lower risk of CVD inpatient hospitalization (HR 0.68, 95% CI 0.55–0.85; p=0.0005). All-cause mortality rates were substantially lower among cases both in those receiving treatment within three years (3.2 vs 30.9 per 1,000 person-years) and in those without early treatment (5.3 vs 55.3 per 1,000 person-years). Conclusion In this nationwide population-based study, women with pregnancy-related heart failure or cardiomyopathy had significantly lower mortality and a reduced risk of cardiovascular hospitalization. These findings suggest that pregnancy-related HF represents a distinct clinical phenotype with a more favorable prognosis than non–pregnancy-related HF in younger women.3-Year All-Cause Mortality: Cases vs Controls3-Year CVD Hosp, Death as Competing