Definition: Given a passage with a question and an answer to that question, classify if the answer actually answers the question into 'yes' or 'no'. Output 'yes' if the answer answers the question and output 'no' if the answer does not answer the question.
Input: Question: Is -blocker therapy associated with adverse outcomes in patients with pulmonary arterial hypertension : a propensity score analysis?
Answer: There was no statistically significant difference in long-term mortality between propensity score-matched pairs of PAH patients with and without -blocker use. These findings need further validation in prospective clinical trials.
Output:
no