Sex and haemodynamics in pulmonary arterial hypertension.

Female sex is a risk factor for pulmonary arterial hypertension (PAH), yet females have better survival than males. We sought to determine if sex was associated with baseline haemodynamics in subjects with PAH, and whether age modified these relationships. We conducted a pooled analysis from 11 randomised trials submitted to the US Food and Drug Administration. The study sample included 1211 subjects with idiopathic PAH, 25% of whom were males, and 489 subjects with connective tissue disease-associated PAH, 13% of whom were males. After multivariable adjustment, right atrial pressure was 1.36 mmHg higher (95% CI 0.44-2.27, p=0.004), cardiac index was -0.14 L · min(-1) · m(-2) lower (95% CI -0.23-0.04, p=0.01) and pulmonary vascular resistance was 1.23 Wood units higher (95% CI 0.18-2.27, p=0.02) in males compared with females. Younger males had 5.43 mmHg (95% CI 2.20-8.66, p=0.001) higher mean pulmonary arterial pressures than younger females, but these relationships were attenuated after age 45 years. In the subgroup of connective tissue disease-associated PAH, males may have had higher right atrial pressure. These findings implicate age as a modifier and provide further evidence of sexual dimorphism in PAH.