Patients with comorbidities, older age, and public insurance are at the highest risk for readmission.

Surgical patients with comorbidities—including congestive heart failure (CHF), chronic obstructive pulmonary disease (COPD), hypertension, end-stage kidney disease, and diabetes —typically suffer from higher rates of postsurgical complications requiring hospital readmission, Craig S. Brown, MD, MSc, of the Department
of Surgery at the University of Michigan in Ann Arbor, and colleagues explained in JAMA Network Open. However, “the underlying mechanisms associated with readmissions after surgery are complex and poorly understood,” they noted, adding that it is difficult to determine the rate of potentially preventable readmissions (PPR) that could be averted with access to outpatient care.

Assessing Preventable Readmissions

Using the ambulatory care sensitive conditions (ACSC) framework adopted by the Agency for Healthcare Research Quality (AHRQ), Dr. Brown and colleagues conducted an analysis to assess the degree to which readmissions are preventable following certain major surgeries. They pulled data from the 2017 Healthcare Cost and Utilization Project (HCUP) NRD to assess all adult inpatient hospitalizations for coronary artery bypass grafting, open abdominal aortic aneurysm repair, lower extremity peripheral arterial bypass, laparoscopic or open colon resection, video-assisted or open thoracoscopic pulmonary lobectomy, total hip arthroplasty, or total knee arthroplasty. The study’s primary outcome was readmission within 90 days following hospital discharge after any of the aforementioned procedures that were considered potentially preventable—a primary diagnosis code for any of the ASCS as defined by the AHRQ, plus three specific categories: superficial surgical site infection, acute kidney injury, and aspiration pneumonia or pneumonitis. Hospital cost estimates were generated using the charge data available for each admission and hospital-level cost-to-charge ratios provided by HCUP.

Nearly 18% of Readmissions Were Preventable

“A total weighted sample of 1,937,354 patients (1,048,046 women [54.1%]; mean age, 66.1 [95% confidence interval (CI), 66.0-66.3]) underwent surgical procedures; 164,755 (8.5%) experienced a readmission within 90 days,” Dr.
Brown and colleagues reported. “Potentially preventable readmissions accounted for 29,321 (17.8%) of all 90-day readmissions, for an estimated total cost to the US healthcare system of approximately $296 million. The most common reasons for PPR were CHF exacerbation (34.6%), pneumonia (12.0%), and acute kidney injury (22.5%). In a multivariable model of adults aged 18-64, patients with public health insurance (Medicare or Medicaid) had more
than twice the odds of PPR compared with those with private insurance (adjusted odds ratio [aOR], 2.09; 95% CI, 1.94-2.25). Among patients aged 65 or older, those with private insurance had 18% lower odds of PPR compared
with those with Medicare as the primary payer (aOR, 0.82; 95% CI, 0.74-0.90).” The study authors added that “each additional decade increase in age was associated with a 20% increase in odds of PPR (aOR, 1.20; 95% CI, 1.17-1.22), and female sex was associated with a 6% increase in odds of PPR (aOR, 1.06; 95% CI, 1.02-1.10). Furthermore, patients treated at metropolitan teaching hospitals had 8% lower odds of PPR compared with patients in a metropolitan nonteaching hospitals (aOR, 0.92; 95% CI, 0.85-0.99)… Emergency surgery was associated with a more than eight-fold increase in the odds of PPR (aOR, 8.24; 95% CI, 7.63-8.92), and several of the comorbidities investigated were associated with increased odds of PPR, including CHF (aOR, 2.99; 95% CI, 2.85-3.13), dementia (aOR, 1.19; 95% CI, 1.11- 1.28), COPD (aOR, 1.51; 95% CI, 1.45-1.57), rheumatoid disease (aOR, 1.15; 95% CI, 1.04- 1.27), diabetes (aOR, 1.54; 95% CI, 1.46-1.62), chronic kidney disease (aOR, 1.77; 95% CI, 1.68-1.85), liver disease (aOR, 1.31; 95% CI, 1.02-1.69), metastatic cancer (aOR, 1.15; 95% CI, 1.03-1.28), and AIDS (aOR, 1.87; 95% CI,
1.25-2.79).”

Important Considerations

The researchers noted that “the difficulty in disentangling the relative responsibility of hospital and patient factors in optimizing the transition from inpatient to outpatient care in the postoperative period, and its applicability to complication associated readmissions has traditionally limited enthusiasm for use of readmissions as a quality
indicator for surgical patients.” However, the results suggest that a large proportion of readmissions in the postoperative setting may be associated with factors linked to transitions from inpatient to outpatient care rather than the inherent risks of the procedure or its complications. “Furthermore, our finding of significant variation in PPR rates across a variety of socioeconomic factors and based on primary payer status, as proxies for access to care, suggests that improved access to ambulatory care may result in decreased rates of readmission for these potentially
preventable causes and significant savings in cost and burden to the health care system as
a whole,” they wrote.