Investigando a hipótese da paridade do poder de compra: um enfoque não linear Testing the long-run purchasing power parity hypothesis: a nonlinear approach

A hipótese da Paridade do Poder de Compra (PPP) é investigada analisando-se a dinâmica de longo prazo da taxa de câmbio real efetiva no Brasil. Com dados mensais, o objetivo principal do estudo é testar a hipótese da PPP com um enfoque não linear. A metodologia empregada baseou-se na aplicação de testes gerais (Keenan, 1985; Tsay, 1986) e específicos para não linearidade do tipo Threshold (Chan, 1990). Seguindo-se a metodologia de Hansen (1999), o estágio seguinte consistiu em testar o número de regimes necessários para descrever a dinâmica não linear da taxa de câmbio real. Os resultados das estimações sugerem a ocorrência de apenas dois regimes distintos, com persistência e volatilidade diferentes. Conclui-se que a hipótese da PPP é apoiada pelos resultados.<br>We consider a threshold time series model in order to test the PPP hypothesis with Brazilian effective real exchange rate dataset in the long run. By following Keenan (1985), Tsay (1986) and Chan (1990), we test Brazilian dataset for several types of nonlinearities. So, after apply Hansen's test to infer about the number of regimes, we apply the more recent methodology of Self-Exciting Threshold Autoregressive (SETAR) model to point out some threshold to which a signal of turning point could be given in the states of the exchange rate dynamics. All the tests suggest that the Brazilian real exchange rate is highly nonlinear. The skeleton of the SETAR models fitted shows that PPP hypothesis is supported in the long run in spite the deviations from short run

Adherence to antithrombotic therapy guidelines improves mortality among elderly patients with atrial fibrillation: insights from the REPOSI study

Background: Atrial fibrillation (AF) is associated with a substantial risk of thromboembolism and mortality, significantly reduced by oral anticoagulation. Adherence to guidelines may lower the risks for both all cause and cardiovascular (CV) deaths. Methods: Our objective was to evaluate if antithrombotic prophylaxis according to the 2012 European Society of Cardiology (ESC) guidelines is associated to a lower rate of adverse outcomes. Data were obtained from REPOSI; a prospective observational study enrolling inpatients aged 6565&nbsp;years. Patients enrolled in 2012 and 2014 discharged with an AF diagnosis were analysed. Results: Among 2535 patients, 558 (22.0&nbsp;%) were discharged with a diagnosis of AF. Based on ESC guidelines, 40.9&nbsp;% of patients were on guideline-adherent thromboprophylaxis, 6.8&nbsp;% were overtreated, and 52.3&nbsp;% were undertreated. Logistic analysis showed that increasing age (p&nbsp;=&nbsp;0.01), heart failure (p&nbsp;=&nbsp;0.04), coronary artery disease (p&nbsp;=&nbsp;0.013), peripheral arterial disease (p&nbsp;=&nbsp;0.03) and concomitant cancer (p&nbsp;=&nbsp;0.003) were associated with non-adherence to guidelines. Specifically, undertreatment was significantly associated with increasing age (p&nbsp;=&nbsp;0.001) and cancer (p&nbsp;&lt;&nbsp;0.001), and inversely associated with HF (p&nbsp;=&nbsp;0.023). AF patients who were guideline adherent had a lower rate of both all-cause death (p&nbsp;=&nbsp;0.007) and CV death (p&nbsp;=&nbsp;0.024) compared to those non-adherent. Kaplan\u2013Meier analysis showed that guideline-adherent patients had a lower cumulative risk for both all-cause (p&nbsp;=&nbsp;0.002) and CV deaths (p&nbsp;=&nbsp;0.011). On Cox regression analysis, guideline adherence was independently associated with a lower risk of all-cause and CV deaths (p&nbsp;=&nbsp;0.019 and p&nbsp;=&nbsp;0.006). Conclusions: Non-adherence to guidelines is highly prevalent among elderly AF patients, despite guideline-adherent treatment being independently associated with lower risk of all-cause and CV deaths. Efforts to improve guideline adherence would lead to better outcomes for elderly AF patients