Researchers Dig Deeper Into Multimorbidity Surgical Risks

By Jonathan Springston, Editor, Relias Media

Updated definitions of multimorbidity could help surgeons decide which older patients are good candidates for certain procedures, according to the authors of an article in press that appeared online this week.

Traditionally, clinicians define multimorbidity as a patient who presents with several comorbidities, which is common among older populations, that can lead to bad outcomes. Typically, the more comorbidities that exist at presentation, the riskier it can be to perform surgery. However, these usually are generic terms applied broadly; the specific existing morbidity that could raise risk might be poorly defined, or other key information might be missing or unknown.

Investigators studied Medicare claims data collected in 2016 and 2017 for patients age 66-90 years who underwent inpatient general, orthopedic, or vascular surgery. The authors used a term called Qualifying Comorbidity Sets (QCS), defined as all comorbidity combinations associated with at least twofold (general/orthopedic procedures) or 1.5-fold (vascular procedures) greater risk of 30-day mortality vs. the overall population who underwent the same procedure.

Then, researchers applied the QCS concept to compare against data collected from 2018 and 2019 (230,410 inpatient general patients, 778,131 orthopedic patients, 146,570 vascular patients). The investigators relied on standard ICD-10 procedure codes to help with their classifications, although they excluded patients older than age 90 years, those with metastatic cancer, and those with Alzheimer’s disease.

Compared to traditional classifications, researchers reported fewer patients labeled as multimorbid under their refined definitions. Among patients who underwent general surgery, the new definition identified 55.9% of the older population compared to 85% of the conventional definition. For orthopedic surgery, it was 40.2% (new definition) vs. 55.9% (conventional definition). For vascular procedures, it was 52.7% (new definition) vs. 96.2% (conventional definition).

Additionally, investigators underscored higher 30-day mortality rates among patients under the new definitions: general surgery, 5.64% (new) vs. 3.96% (conventional); orthopedic surgery, 1.68% (new) vs. 1.13% (conventional); and vascular surgery, 7% (new) vs. 4.43% (conventional).

“I was surprised at how profound the increases in mortality were for some of these QCSs,” said lead study author Omar I. Ramadan, MD, MSc, a general surgery resident at the University of Pennsylvania Perelman School of Medicine. “For example, in general surgery, a patient who is wheelchair- or hospital bed-bound and has thrombocytopenia and other hematological disorders is 18 times more likely to die within 30 days than a patient who is not multimorbid undergoing the same procedure.”

Ramadan and colleagues reported the highest-risk QCS for general surgery was home hospital bed or wheelchair use, combined with thrombocytopenia and other hematological disorders. For orthopedic surgery, protein-calorie malnutrition was highest. For vascular surgery, acute heart or respiratory failure were the highest.

Investigators went even further with their evaluations, exploring connections between facility quality and patient outcomes. The authors used several benchmarks to define quality, including patient-to-bed ratio, whether the facility is a teaching hospital, surgical patient volume, and nurse skills. Researchers noted that higher-quality facilities delivered better mortality benefits for multimorbid vs. non-multimorbid general and orthopedic procedure patients. However, that was not the case for vascular surgery patients.

“Our new multimorbidity definitions identified far more specific, higher-risk pools of patients than conventional definitions, potentially aiding clinical decision-making,” the authors concluded.

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