Pulmonary hospitalizations and ischemic heart disease events in patients with peripheral artery disease

The prognostic significance of acute pulmonary events in people with lower extremity peripheral artery disease (PAD) is unknown. We hypothesized that an acute pulmonary event (hospitalization for pneumonia and/or chronic lower respiratory disease (CLRD) exacerbation) would be associated with a higher rate of subsequent ischemic heart disease (IHD) events in PAD. A total of 569 PAD participants were systematically identified from among patients in Chicago medical practices and followed longitudinally. Hospitalizations after enrollment were evaluated and adjudicated for pulmonary events. The primary outcome was adjudicated myocardial infarctions, unstable angina, and IHD death. Of 569 PAD participants, 34 (6.0%) were hospitalized for a pulmonary event (11 CLRD exacerbation and 23 pneumonia) during a mean follow-up of 1.52 years±0.80. Participants hospitalized for a pulmonary event had a higher rate of subsequent IHD events than those not hospitalized for a pulmonary event (10/34 (29%) vs 38/535 (7.1%), p<0.001). After adjusting for age, sex, race, comorbidities, and other confounders, a pulmonary hospitalization was associated with an increased risk of a subsequent IHD event (hazard ratio (HR) = 12.42, 95% confidence interval (CI) = 5.35 to 28.86, p<0.001). Non-pulmonary hospitalizations were also associated with IHD events (HR = 3.39, 95% CI = 1.78 to 6.44, p<0.001), but this association was less strong compared to pulmonary hospitalizations and IHD events (p = 0.011 for difference in the strength of association). In conclusion, hospitalization for an acute pulmonary event was associated with higher risk for subsequent IHD events in PAD. Future study should examine whether hospitalization for pulmonary events warrants increased surveillance or potential intervention to prevent IHD events in PAD.