Efficacy of Sildenafil on healthy humans in high­altitude hypoxia at rest and during exercise: A meta­analysis.

The current meta-analysis aimed to fully evaluate the efficacy of Sildenafil in healthy humans at different altitudes, focusing on echocardiographic and hemodynamic parameters. Relevant studies were retrieved from the Cochrane, Embase and PubMed databases. Odds ratios (OR) were determined for dichotomous data and weighted mean differences with 95% confidence intervals (CIs) for continuous data. A total of 16 RCTs were included in the current meta-analysis. Short-term treatment with Sildenafil significantly elevated resting heart rate (P<0.01) at altitudes <4,000 meters. No significant differences in heart rate were observed between the Sildenafil and placebo groups at rest and during exercise at an altitude of >4,000 meters (P>0.05). Sildenafil improved resting cardiac output at an altitude of >5,000 meters (P<0.01) and exercising arterial oxygen saturation at <4,000 meters (P<0.01). Sildenafil reduced resting pulmonary artery systolic pressure (PASP) at altitudes >4,000 meters (P<0.01) and exercising PASP at altitudes >5,000 meters (P<0.01). Therefore, Sildenafil efficacy in healthy humans with high-altitude hypoxia is related to altitude and rest or exercise.

Sleep disturbance and quality of life among university freshmen in Qinghai-Tibet Plateau of China.

Purpose: University freshmen are particularly vulnerable as they are undergoing the transition from high school to university with a range of changes. Sleep problems among this group in the Qinghai-Tibet Plateau of China were barely studied. This study aimed to explore sleep disturbance, and its association with quality of life (QoL) and demographic and clinical characteristics among university freshmen in Qinghai-Tibet Plateau, China. Methods: A multistage stratified cluster random sampling method was performed to recruit student participants with a structured questionnaire to collect sociodemographic and clinical characteristics, and lifestyle behaviors. Sleep disturbance including three aspects of sleep disturbance (i.e., difficulty initiating sleep (DIS), difficulty maintaining sleep (DMS), and early morning awakening (EMA)) was assessed using standardized measurement. Multiple logistic regression models were applied to analyze the data. Results: Among included 2,769 freshmen, the prevalence of sleep disturbance was 14.8% (95% CI: 14.2-15.5%), and corresponding prevalence of DIS, DMS, and EMA was 8.2% (95% CI: 7.7-8.7%), 8.3% (95% CI: 7.8-8.8%), and 4.2% (95% CI: 3.8-4.6%), respectively. Freshmen with sleeping disturbance had significantly lower QoL in physical [F (1, 2769) = 60.23, p < 0.001], psychological [F (1, 2769) = 46.18, p < 0.001], social [F (1, 2769) = 23.04, p < 0.001], and environment [F (1, 2769) = 6.07, p = 0.01] domains. Multiple logistic regression analyses revealed that having breakfast five times a week or less (less than three times, OR = 1.79, 95% CI: 1.34-2.40; 3-5 times, OR = 1.40, 95% CI: 1.09-1.79), self-perceived severe Internet dependence (OR = 1.71, 95% CI: 1.11-2.65), self-perceived poor health status (OR = 3.44, 95% CI: 2.06-5.74), high academic stress (OR = 1.42, 95% CI: 1.13-1.78), poor relationship with classmates (OR = 3.44, 95% CI: 1.53-7.71), and severe ADHD symptoms (OR = 1.08, 95% CI: 1.05-1.12) were positively associated with sleeping disturbance. Conclusion: Sleep disturbance was common among freshmen and is associated with poorer QoL. Prevention and intervention strategies should be developed and implemented, especially among the vulnerable university freshman groups.

Cognitive Impairment and Its Associated Factors in Older Adults Living in High and Low Altitude Areas: A Comparative Study.

Background: Cognitive impairment is a major health concern in older adults. Few studies have examined the association between environmental factors and cognitive impairment, especially in high altitude areas. In this study, the prevalence of cognitive impairment in older adults living in high altitude was compared with those living in low altitude areas. Methods: This was a comparative study conducted at Qinghai (high altitude group), and Guangzhou (low altitude group), China. Cognition, depressive symptoms and quality of life (QOL) were assessed using the Montreal Cognitive Assessment (MoCA), Patient Health Questionnaire (PHQ-9) and WHO Quality of Life brief version-WHOQOL-BREF, respectively. Results: Altogether, 644 older adults (207 in Qinghai and 437 in Guangzhou) completed the assessment. The prevalence rate of cognitive impairment was 94.7% (95% CI: 91.6-97.7%) in older adults living in the high altitude area, while the corresponding figure was 89.2% (95% CI: 86.3-92.1%) in the low altitude area. After controlling for covariates, the high altitude group appeared more likely to have cognitive impairment (OR = 2.92, 95% CI: 1.23-6.91, P = 0.015) compared with the low altitude group. Within the high altitude group sample, multinomial logistic regression analysis revealed that older age (aged 74 and above) was significantly associated with higher risk of severe cognitive impairment (OR = 3.58, 95%CI: 1.44-8.93, P = 0.006), while higher education level (secondary school and above) was associated with decreased risk of moderate cognitive impairment (OR = 0.43, 95%CI: 0.22-0.85, P = 0.006). Within the high altitude group, QOL did not differ significantly between normal/mild, moderate and severe cognitive impairment subgroups across physical [F (1, 207) = 1.83, P = 0.163], psychological [F (1, 207) = 1.50, P = 0.225], social [F (1,207) = 2.22, P = 0.111] and environmental domains [F (1,207) = 0.49, P = 0.614]. Conclusion: This study found that cognitive impairment was more common among older adults living in the high altitude area. Regular screening and appropriate interventions should be provided to older adults in need.

A meta-analysis of the safety and efficacy of bosentan therapy combined with prostacyclin analogues or phosphodiesterase type-5 inhibitors for pulmonary arterial hypertension.

Bosentan is an effective drug for the treatment of pulmonary arterial hypertension (PAH). The aim of the present meta-analysis was to examine the evidence concerning the efficacy and safety of bosentan therapy combined with prostacyclin analogues or phosphodiesterase type 5 (PDE-5) inhibitors for treating PAH. Eligible published studies were collected from Embase, PubMed, The Cochrane Library and the www.clinicaltrials.gov website. Heterogeneity was assessed using the Cochran Q-statistic test. Results were presented as risk ratios or mean differences with 95% confidence intervals (CI). A total of five studies, comprising 310 patients were included for analysis. No significant improvements in six-minute walk distance (6MWD; mean difference, 16.43 m), clinical worsening (risk ratio, 0.54) and the World Health Organization functional classification (class I: risk ratio, 1.17; class II: risk ratio, 1.18) were observed in patients treated with bosentan in combination with prostacyclin analogues or PDE-5 inhibitors. However, a significant reduction in the mean pulmonary artery pressure (mPAP; 95% CI: -17.06, -6.83; P<0.0001) following bosentan combination therapy was observed. Comparisons of adverse event rates in the bosentan combination therapy (55.6%) and monotherapy (51.8%) suggested that there is no reduction in adverse events (risk ratio, 1.10). The results indicated that bosentan combined with prostacyclin analogues or PDE-5 inhibitors may not improve 6MWD, cardiac function, clinical worsening and adverse events. However, bosentan combined with prostacyclin analogues or PDE-5 inhibitor therapy was able to significantly reduce mPAP compared with the effect of bosentan monotherapy.