High Regional Primary Care Use Associated with Less Critical Illness

Andrew J. Admon, MD, MPH

Regions with higher rates of primary care were found to be associated with reduced rates of critical illness, as measured by admissions to intensive care units (ICUs) and mechanical ventilation use. Results from this cross-sectional, ecological study were presented at the 2019 American Thoracic Society (ATS) International Conference in Dallas, TX.

“If confirmed in other studies, this finding suggests that some of the costliest, most devastating illnesses might be prevented by investing in our primary care infrastructure and efforts to increase its use,” said Andrew J. Admon, MD, MPH, a Fellow in Pulmonary and Critical Care Medicine in the Department of Internal Medicine at the University of Michigan in an interview with MD Magazine®.

The study found that increased use of primary care was associated with both potentially preventable as well as all-cause ICU admissions and respiratory failure. Admon said the association between primary care use and reduced all-cause critical illness and respiratory failures was a surprising result. “This suggests that many more episodes of critical illness and respiratory failure may be sensitive to outpatient care than previously defined,” he added.

Investigators used Medicare data from January 2014 to September 2015 from 2,441,999 patients in 306 hospital referral regions. They looked at rates of ICU admissions and mechanical ventilation. Investigators also analyzed separately, the ICD-9-CM codes for ambulatory care sensitive conditions (ACSCs), defined as diagnoses where timely ambulatory care would have prevented the need for hospitalization.

In the bottom decile of regions, primary care use was 69.1% while this was 81.4% in the top decile.

After adjustments, investigators found that a 10% absolute increase in primary care use was associated with a 12.7 decline in all cause ICU admissions per 1000 Medicare beneficiaries (95% CI, -20.0 to -5.4; P = .001). Additionally, a 10% increase in primary care use was associated with a 1.5 per 1000 decline in ACSC ICU admissions (95% CI, -2.7 to -0.4; P = .010), a 3.4 per 1000 decline in all-cause mechanical ventilation (95% CI, -4.9 to -1.9; P <.001), and a 0.8 per 1000 decline in ACSC mechanical ventilation (95% CI, -1.2 to -0.3; P = .001).

“As intensivists, many of us have admitted patients who seemed to have fallen through the cracks, and whose critical illness probably could have been stemmed with a well-timed clinic visit or medication prescription a few weeks back,” Admon told MD Mag. “This work lends support to this clinical observation that many of us have made and starts to put numbers to it.”

Many more questions remain to be investigated, and Admon highlighted a few areas in need of more research.

“The factors that eventually lead a patient to develop critical illness might begin weeks or months before we see them in the ICU. Future work should confirm this finding in individual level data, begin to identify patients at high risk, and understand ways to optimize the use of primary care among them,” said Admon.

The abstract, “Regional Rates of Primary Care Visits, ICU Admission, and Mechanical Ventilation,” was presented on May 21 at the ATS 2019 International Conference.