Differential effects of size-specific particulate matter on emergency department visits for respiratory and cardiovascular diseases in Guangzhou, China

BACKGROUND

Studies differentiating the cardiorespiratory morbidity effects of PM_2.5, PM₁₀, and PM_2.5∼10 (i.e. coarse PM or PMc) are still limited and inconsistent.

OBJECTIVE

To estimate the acute, cumulative, and harvesting effects of exposure to the three size-specific PM on cardiorespiratory morbidity, and their concentration-response relations.

METHODS

A total of 6,727,439 emergency department (ED) visits were collected from 16 public teaching hospitals in Guangzhou, from January 1st 2012 to December 31st 2015, among which over 2.1 million were asthma, COPD, pneumonia, respiratory tract infection (RTI), hypertension, stroke, and coronary heart disease (CHD). Distributed lag non-linear models (DLNM) was used to estimate the associations between the three size-specific PM and ED visits for the cardiovascular diseases. Long-term trends, seasonality, influenza epidemics, meteorological factors, and other gas pollutants, including SO2, NO₂, and O₃, were adjusted. We stratified the analyses by gender and age.

RESULTS

Elevated PM_2.5 and PM₁₀ were significantly associated with increased ED visits for pneumonia, RTI, and CHD at both lag₀ and lag_0-3. A 10 μg/m³ increment of PMc (at lag_0-14) was estimated to increase ED visits for pneumonia by 6.32% (95% CI, 4.19, 8.49) and for RTI by 4.72% (95% CI, 3.81, 5.63), respectively. PMc showed stronger cumulative effects on asthma in children than elderly. We observed significant harvesting effects (i.e. morbidity displacements) of the three size-specific PM on respiratory but very little on cardiovascular ED visits. The concentration-response curves suggested non-linear relations between exposures to the three different sizes of PM and respiratory morbidity.

CONCLUSIONS

Overall, the three size-specific PM demonstrated distinct acute and cumulative effects on the cardiorespiratory diseases. PM_2.5 and PMc would have significant effects on pneumonia and RTI. Strategies should be considered to further reduce levels of ambient PM_2.5 and PMc.

Cardiorespiratory morbidity and mortality of opioid overdose during admission to safety-net hospitals

STUDY OBJECTIVE

Safety-net hospitals disproportionately care for high-risk patients. Prior work has shown safety-net hospitals to have inferior postoperative outcomes with higher cost and worse patient ratings. We aim to examine the association of hospital safety-net burden with morbidity and mortality in patients with opioid overdose hospital admission.

DESIGN

Retrospective cross-sectional analysis using the National Inpatient Sample registry from 2010 to 2014.

SETTING

Multi-institutional.

PATIENTS

We included 547, 399 patients admitted to a United States hospital with an International Classification of Disease, Ninth Revision, code of opioid overdose. To study the association of hospital safety-net burden on mortality and morbidity, we calculated hospital safety-net burden defined as the percent of Medicaid or uninsured among all admitted patients. Hospitals were categorized into one of three categories: low burden hospitals, medium burden hospitals, and high burden hospitals (i.e., safety-net hospitals). We performed a mixed effects multivariable logistic regression analysis to assess the association of hospital safety-net burden with short-term inpatient outcomes.

INTERVENTION

None.

MEASUREMENTS

The primary outcomes were inpatient mortality and morbidity.

MAIN RESULTS

Compared to MBHs and LBHs, HBHs had a greater proportion of minority patients (i.e., Black, Hispanic, and Native American) and patients with median household income in the lowest quartile (p < 0.001). Among prescription opioid overdose admissions, the odds of inpatient mortality and pulmonary and cardiac morbidity were also not significantly higher between HBHs versus LBHs (p > 0.05).

CONCLUSIONS

Safety-net hospital disproportionately care for vulnerable populations, however the odds of poor outcomes were no different in opioid overdose. Safety-net hospitals should have equal access to the funding and resources that allows them to deliver the same standard of care as their counterparts.

A multicity study of air pollution and cardiorespiratory emergency department visits: Comparing approaches for combining estimates across cities

Determining how associations between ambient air pollution and health vary by specific outcome is important for developing public health interventions. We estimated associations between twelve ambient air pollutants of both primary (e.g. nitrogen oxides) and secondary (e.g. ozone and sulfate) origin and cardiorespiratory emergency department (ED) visits for 8 specific outcomes in five U.S. cities including Atlanta, GA; Birmingham, AL; Dallas, TX; Pittsburgh, PA; St. Louis, MO. For each city, we fitted overdispersed Poisson time-series models to estimate associations between each pollutant and specific outcome. To estimate multicity and posterior city-specific associations, we developed a Bayesian multicity multi-outcome (MCM) model that pools information across cities using data from all specific outcomes. We fitted single pollutant models as well as models with multipollutant components using a two-stage chemical mixtures approach. Posterior city-specific associations from the MCM models were somewhat attenuated, with smaller standard errors, compared to associations from time-series regression models. We found positive associations of both primary and secondary pollutants with respiratory disease ED visits. There was some indication that primary pollutants, particularly nitrogen oxides, were also associated with cardiovascular disease ED visits. Bayesian models can help to synthesize findings across multiple outcomes and cities by providing posterior city-specific associations building on variation and similarities across the multiple sources of available information.