Association of fine particulate matter exposure with acute noncardiovascular critical illnesses and in-hospital outcomes in patients receiving intensive cardiac care

BACKGROUND: The effect of short-term exposure to fine particulate matter (PM(2.5)) on the incidence of acute noncardiovascular critical illnesses (ANCIs) and clinical outcomes is unknown in patients with acute cardiovascular diseases. METHODS: We conducted a retrospective study in 2337 admissions to an intensive cardiac care unit (ICCU) from June 2016 to May 2017. We used the 2-day average PM(2.5) concentration before ICCU admission to estimate the individual exposure level, and patients were divided into 3 groups according to the concentration tertiles. Major ANCI was defined as the composite of acute respiratory failure, acute kidney injury, gastrointestinal hemorrhage, or sepsis. The primary endpoint was all-cause death or discharge against medical advice in extremely critical condition. RESULTS: During the 12-month study period, the annual median concentration of PM(2.5) in Chengdu, China was 48 μg/m(3) (IQR, 33–77 μg/m(3)). More than 20% of admissions were complicated by major ANCI, and the primary endpoints occurred in 7.6% of patients during their hospitalization. The association of short-term PM(2.5) exposure levels with the incidence of acute respiratory failure (adjusted OR [odds ratio] =1.31, 95% CI [confidence interval]1.12–1.54) and acute kidney injury (adjusted OR = 1.20, 95% CI 1.02–1.41) showed a significant trend. Additionally, there were numerically more cases of sepsis (adjusted OR = 1.21, 95% CI 0.92–1.60) and gastrointestinal hemorrhage (adjusted OR = 1.29, 95% CI 0.94–1.77) in patients with higher exposure levels. After further multivariable adjustment, short-term PM(2.5) exposure levels were still significantly associated with incident major ANCI (adjusted OR = 1.32, 95% CI 1.12–1.56), as well as a higher incidence of the primary endpoint (adjusted OR = 1.52, 95% CI 1.09–2.12). CONCLUSION: Short-term PM(2.5) exposure before ICCU admission was associated with an increased risk of incident major ANCI and worse in-hospital outcomes in patients receiving intensive cardiac care.