bronchitis. Congestive heart failure was the primary diagnosis for 19% of the PH hospitalizations in 2001 to 2002 and for 18% in 2009 to 2010. The top three diagnoses accounted for 43% of the hospitalizations in 2001 to 2002 and for 37% in 2009 to 2010. Pneumonia and cardiac dysrhythmias rounded out the five leading principal diagnoses, except in 2007 to 2008, when respiratory failure was the fifth most common principal diagnosis. Acute myocardial infarction moved from the sixth most frequent principal diagnosis in 2001 to 2002 to the 10th most frequent in 2009 to 2010. Nephritis, nephrotic syndrome, and nephrosis first appeared as the 10th most common primary diagnosis in 2007 to 2008 and moved up to the seventh most common primary diagnosis in 2009 to 2010.

######rate for men actually declined from 1980 through 2002; information in this report shows that the rates for men continued to decline until 2006 and then began increasing. In general, between 2001 and 2010, mortality rates from COPD declined among men^[@r12]^ and this may explain, in part, the long-term decline in mortality among men with PH that was trending from 1980 to 2006. Reasons for the reversal in trend for men are unclear, but the previous decline may have been associated with reductions in COPD and emphysema, which the current analysis identifies as well. On the other hand, we identified increases in the rates of PH mortality in association with coronary heart disease and hypertension as well as autoimmune disease in men. Few studies have found male sex