New study links higher postoperative mortality to income level

A study from Canadian and Australian researchers has found that lower neighborhood income is associated with higher postoperative mortality, and suggests that improving surgical outcomes may require addressing disparities in social determinants of health.

The study, published this week on JAMA Network Open, sought to answer the question, “How are social determinants of health (neighborhood income, immigration status, and migration recency) associated with 30-day mortality after inpatient elective surgery in a universal health care system?”

Although the study focuses on outcomes of patients receiving surgeries through universal health care systems, its findings can further inform American surgical facilities on how they should better address potentially dangerous inequities in postoperative care after elective procedures in inpatient environments.

The cohort study, which evaluated over one million adult Canadian patients who underwent scheduled surgical procedures from 2017 through 2023, found that “patients from the lowest-income neighborhoods had higher odds of 30-day mortality than those from the highest-income areas, even after adjusting for patient, procedure, and hospital factors.” The researchers say “the association showed a dose-response pattern and persisted across study periods; immigration-related factors were not associated with mortality.”

The researchers note that prior research conducted in private for-profit health care systems has likewise suggested that social determinants of health play a role in adverse postoperative outcomes.

Of the million-plus patients studied, 1,780 (0.9%) from the lowest-income areas died, while 1,307 (0.6%) from the highest-income areas died. The researchers found that patients from the lowest-income areas were at 52% increased odds of death compared with those from the highest-income areas. “A dose-response association was demonstrated between neighborhood income and mortality, with odds of death increasing with diminishing income,” they wrote. “There was evidence of effect modification of the association between neighborhood income and mortality by procedure complexity. Immigrant and refugee status and recent migration demonstrated reduced odds of mortality in unadjusted analyses, but these associations diminished with risk adjustment.”

Read the full study here.