Infectious disease deaths decline, but U.S. sees wide disparity in outcomes

Fewer Americans are dying from infectious diseases compared to three decades ago, but the outcome gap between rural and urban areas of the country has widened, according to a new study.

Deaths from infectious diseases decreased by 18% in the U.S. between 1980 and 2014, according to a study published Tuesday in JAMA, dropping from 42 deaths per 100,000 people to 34 deaths per 100,000.

But rural counties aren't seeing the same improvements in infectious disease mortality as their urban counterparts, researchers found. One of the biggest drivers of that inequality is the steady decline in access to healthcare services in many rural areas.

"As a country we are doing much better, but certain counties are still lagging behind and are in fact getting worse," said study co-author Ali Mokdad, professor of global health and epidemiology at the University of Washington School of Public Health.

Lower respiratory infection was the leading cause of mortality in 2014, accounting for more than 78% of all infectious disease deaths that year. Such infections can include conditions commonly caused by environmental pollutants such as pneumonia, bronchitis and asthma.

Lower respiratory infection also had the largest mortality disparities. Counties ranked in the lower 10th percentile had an average of only 18 deaths for every 100,000 people while counties that ranked in the 90th percentile had 43 deaths per 100,000.

A 2017 Centers for Diseases Control and Prevention report found death rates for heart disease, cancer, unintentional injury, chronic lower respiratory disease and stroke were all higher in rural areas compared to urban environments. Like Tuesday's study, the CDC report suggested a combination of limited healthcare access and a higher frequency of health-risk behaviors were major contributors to those outcomes.

Mokdad said factors such as lower income level and education, limited access to quality care and higher frequency of health-risk behaviors like smoking, substance use and obesity can usually predict the health outcomes of a community, regardless of the disease.

He said people living in medically underserved areas often go through a vicious cycle of engaging in unhealthy behaviors when they can't access healthcare services consistently or take advantage of preventive services. Such individuals often delay seeking treatment until their condition has become more advanced, reducing their chances of recovery.

"People under stress are more likely to behave badly," Mokdad said.

Mokdad said such societal factors help to explain why so many rural communities have been hit hard by the opioid epidemic in both the high proportion of drug overdose deaths and the number of those who have died from infectious diseases like HIV/AIDS and tuberculosis; both of the latter are heavily concentrated in the Southeast.

Health departments and healthcare providers in rural areas must first identify the specific issues on a neighborhood level in order see significant progress toward improving their health outcomes, said Dr. Jeffery Duchin, public health officer for Seattle and King County in Washington.

"We find that we have basically a 20-year spread in life expectancy between people living in different parts of our county," Duchin said. "So, knowing who's at risk within your county is the most important thing."

Improving healthcare access and quality alone is not enough to address the underlying issues that created such disparities, according to Duchin. He said providers need to look at how they can address non-medical, societal factors such as poverty, crime, lack of stable housing, and food insecurity in order to affect long-term change.

"In order to decrease health disparities across any geographic area, be it a county or our country, we really need to address the upstream drivers of poor health in addition to providing good access to quality medical care to everyone," Duchin said.