Exposure to Air Pollution Increases Hospital Admissions and Health Insurance Costs

Short-term exposure to fine particulate matter with diameter less than 2.5 µm (PM2.5) is associated with increased rates of hospital admissions and health insurance costs, according to the findings of a recent study published in BMJ.

In this time-stratified, case crossover study, researchers assessed Medicare inpatient hospital claims of 95,277,169 patients aged 65 and older between 2000 and 2012. The study’s primary endpoint was stipulated as the risk of hospital admission, number of admissions, days in hospital, inpatient and post-acute care costs, and value of statistical life (that is, the economic value used to measure the cost of avoiding a death) due to the lives lost at discharge for 214 disease groups.

Following study analysis, researchers observed associations between short term exposure to PM2.5 and an increased risk of hospital admission in diseases, such as septicemia, fluid and electrolyte disorders, and acute and unspecified renal failure. They also found a positive association between the risk of hospital admission and cardiovascular and respiratory diseases, Parkinson’s disease, diabetes, phlebitis, thrombophlebitis, and thromboembolism. The study authors wrote that “These associations remained consistent when restricted to days with a daily PM2.5 concentration below the WHO air quality guideline for the 24-hour average exposure to PM2.5.”

Moreover, for the rarely studied diseases, each short-term increase in exposure to 1 µg/m3 short term PM2.5 was linked with an annual increase of 2,050 hospital admissions (95% CI, 1,914 to 2,187), 12,216 days in hospital (95% CI, 11,358 to 13,075), as well as inpatient and post-admission costs ($31 million), and $2.5 billion in value of statistical life. For diseases with a previously known association, the researchers observed that each 1 µg/m3 increase in short term exposure to PM2.5 was associated with an annual increase of 3,642 hospital admissions (95% CI, 3,434 to 3,851), 20,098 days in hospital (95% CI, 18, 950 to 21,247), $69 million in inpatient and post-acute care costs, and $4.1 billion in value of statistical life.

“New causes and previously identified causes of hospital admission associated with short term exposure to PM2.5 were found,” the researchers wrote in their conclusion. “These associations remained even at a daily PM2.5 concentration below the WHO 24-hour guideline. Substantial economic costs were linked to a small increase in short term PM2.5.”