Sex and menopause differences in response to tadalafil: 6-minute walk distance and time to clinical worsening

Investigating the "sex paradox" in pulmonary arterial hypertension: Results from the Pulmonary Hypertension Association Registry (PHAR)

BACKGROUND

Female sex is a significant risk factor for pulmonary arterial hypertension (PAH), yet males with PAH have worse survival - a phenomenon referred to as the "sex paradox" in PAH.

METHODS

All adult PAH patients in the Pulmonary Hypertension Association Registry (PHAR) with congruent sex and gender were included. Baseline differences in demographics, hemodynamics, functional parameters, and quality of life were assessed by sex. Kaplan-Meier survival analysis was used to evaluate survival by sex. Mediation analysis was conducted with Cox proportional hazards regression by comparing the unadjusted hazard ratios for sex before and after adjustment for covariates. The plausibility of collider-stratification bias was assessed by modeling how large an unmeasured factor would have to be to generate the observed sex-based mortality differences. Subgroup analysis was performed on idiopathic and incident patients.

RESULTS

Among the 1,891 patients included, 75% were female. Compared to men, women had less favorable hemodynamics, lower 6-minute walk distance, more PAH therapies, and worse functional class; however, sex-based differences were less pronounced when accounting for body surface area or expected variability by gender. On multivariate analysis, women had a 48% lower risk of death compared to men (Hazard Ratio 0.52, 95% Confidence interval 0.36 - 0.74, p < 0.001). Modeling found that under reasonable assumptions collider-stratification could account for sex-based differences in mortality.

CONCLUSIONS

In this large registry of PAH patients new to a care center, men had worse survival than women despite having more favorable baseline characteristics. Collider-stratification bias could account for the observed greater mortality among men.

Pulmonary arterial hypertension: Sex matters

Pulmonary arterial hypertension (PAH) is a complex disease of multifactorial origin. While registries have demonstrated that women are more susceptible to the disease, females with PAH have superior right ventricle (RV) function and a better prognosis than their male counterparts, a phenomenon referred to as the 'estrogen paradox'. Numerous pre-clinical studies have investigated the involvement of sex hormones in PAH pathobiology, often with conflicting results. However, recent advances suggest that abnormal estrogen synthesis, metabolism and signalling underpin the sexual dimorphism of this disease. Other sex hormones, such as progesterone, testosterone and dehydroepiandrosterone may also play a role. Several non-hormonal factor including sex chromosomes and epigenetics have also been implicated. Though the underlying pathophysiological mechanisms are complex, several compounds that modulate sex hormones levels and signalling are under investigation in PAH patients. Further elucidation of the estrogen paradox will set the stage for the identification of additional therapeutic targets for this disease.

Sex and gender in pulmonary arterial hypertension

Pulmonary arterial hypertension (PAH) is a rare disease characterised by pulmonary vascular remodelling and elevated pulmonary pressure, which eventually leads to right heart failure and death. Registries worldwide have noted a female predominance of the disease, spurring particular interest in hormonal involvement in the disease pathobiology. Several experimental models have shown both protective and deleterious effects of oestrogens, suggesting that complex mechanisms participate in PAH pathogenesis. In fact, oestrogen metabolites as well as receptors and enzymes implicated in oestrogen signalling pathways and associated conditions such as BMPR2 mutation contribute to PAH penetrance more specifically in women. Conversely, females have better right ventricular function, translating to a better prognosis. Along with right ventricular adaptation, women tend to respond to PAH treatment differently from men. As some young women suffer from PAH, contraception is of particular importance, considering that pregnancy in patients with PAH is strongly discouraged due to high risk of death. When contraception measures fail, pregnant women need a multidisciplinary team-based approach. This article aims to review epidemiology, mechanisms underlying the higher female predominance, but better prognosis and the intricacies in management of women affected by PAH.

Efectos del tadalafilo en el deseo sexual y la excitación/lubricación en mujeres postmenopáusicas

Objetivo Determinar los efectos y la seguridad del tadalafilo en el deseo sexual y la excitación/lubricación en mujeres postmenopáusicas.

Métodos Estudio cuasi experimental (con comparación antes de la intervención y después), con seguimiento de la cohorte de pacientes: 228 mujeres mayores de 40 años en postmenopausia, que consultaron por bajo deseo sexual y alteración de la excitación /lubricación, en una clínica sexológica en Armenia (Colombia), entre 2018 y 2019. Las mujeres recibieron 2,5 mg diarios de tadalafilo durante 12 semanas. Se determinaron las puntuaciones del instrumento, el Índice de Función Sexual Femenina (IFSF), cada cuatro semanas.

Resultados El promedio de edad fue de 54,36 ± 4,92 años. Antes del tratamiento, la media en la puntuación del IFSF fue de 22,41 puntos (intervalo de confianza del 95% [IC95%]: 7,11–29,76); a las 4 semanas, 24,73 puntos (IC95%: 23,51–30,28); a las 8 semanas, 25,97 puntos (IC95%: 24,26–31,53); y, al final, 26,99 puntos (IC95%: 25,97–32,46), con diferencias estadísticamente significativas entre las 4 medidas pareadas (p < 0,001). La excitación fue el dominio con mayor puntuación tras el tratamiento (4,83 puntos; IC 95%: 4,36–4,91), seguida por la lubricación (4,77 puntos; IC95%: 4,28–4,87). El deseo sexual mostró un significativo incremento al final del estudio (4,29 puntos; IC95%: 4,07–4,39). Se presentaron efectos adversos leves. Se observó una satisfacción con el consumo de tadalafilo del 84,21%.

Conclusiones El tratamiento diario con 2,5 mg de tadalafilo genera mejoría en la función sexual de mujeres en la postmenopausia, y el incremento en la puntuación del IFSF demuestra su efecto positivo.

Sex differences in hemodynamic responses and long-term survival to optimal medical therapy in patients with pulmonary arterial hypertension

It is widely known that the incidence of pulmonary arterial hypertension (PAH) is higher in female, whereas prognosis is poorer in male patients. However, sex differences in hemodynamic response to and long-term prognosis with PAH-targeted treatment in the modern era remain to be fully elucidated. We examined the long-term prognosis of 129 consecutive PAH patients (34 males and 95 females) diagnosed in our hospital from April 1999 to October 2014, and assessed hemodynamic changes in response to PAH-targeted therapy. Female patients had better 5-year survival compared with male patients (74.0 vs. 53.4%, P = 0.003); however, higher age quartiles in females were associated with poor outcome. Follow-up examination after medical treatment showed significant decreases in mean pulmonary arterial pressure (mPAP), pulmonary vascular resistance (PVR), and pulmonary arterial capacitance (PAC) in both sexes (both P < 0.05), whereas only females had a significant improvement in right ventricular end-diastolic pressure (RVEDP), right atrial pressure (RAP), cardiac index, and mixed venous oxygen saturation (SvO₂) (all P < 0.05). Baseline age significantly correlated with the hemodynamic changes only in female patients; particularly, there were significant sex interactions in RVEDP and RAP (both P < 0.10). The multivariable analysis showed that SvO₂ at baseline and mPAP and SvO₂ at follow-up were significant prognostic factors in males, whereas the changes in mPAP, PVR, and PAC and use of endothelin-receptor antagonist in females. These results indicate that female PAH patients have better long-term prognosis than males, for which better improvements of right ventricular functions and hemodynamics may be involved.

Novel approach to classifying patients with pulmonary arterial hypertension using cluster analysis

Pulmonary arterial hypertension (PAH) patients have distinct disease courses and responses to treatment, but current diagnostic and treatment schemes provide limited insight. We aimed to see if cluster analysis could distinguish clinical phenotypes in PAH. An unbiased cluster analysis was performed on 17 baseline clinical variables of PAH patients from the FREEDOM-M, FREEDOM-C, and FREEDOM-C2 randomized trials of oral treprostinil versus placebo. Participants were either treatment-naïve (FREEDOM-M) or on background therapy (FREEDOM-C, FREEDOM-C2). We tested for association of clusters with outcomes and interaction with respect to treatment. Primary outcome was 6-minute walking distance (6MWD) change. We included 966 participants with 12-week (FREEDOM-M) or 16-week (FREEDOM-C and FREEDOM-C2) follow-up. Four patient clusters were identified. Compared with Clusters 1 (n = 131) and 2 (n = 496), Clusters 3 (n = 246) and 4 (n = 93) patients were older, heavier, had worse baseline functional class, 6MWD, Borg Dyspnea Index, and fewer years since PAH diagnosis. Clusters also differed by PAH etiology and background therapies, but not gender or race. Mean treatment effect of oral treprostinil differed across Clusters 1-4 increased in a monotonic fashion (Cluster 1: 10.9 m; Cluster 2: 13.0 m; Cluster 3: 25.0 m; Cluster 4: 50.9 m; interaction P value = 0.048). We identified four distinct clusters of PAH patients based on common patient characteristics. Patients who were older, diagnosed with PAH for a shorter period, and had worse baseline symptoms and exercise capacity had the greatest response to oral treprostinil treatment.