Defining Multimorbidity in Older Surgical Patients

Area of Science:

• Gerontology
• Surgical Outcomes
• Epidemiology

Background:

• Multimorbidity (MM) lacks a standardized definition, hindering systematic analysis of comorbidity interactions.
• Existing research often overlooks specific comorbidity combinations and multiple testing issues in large datasets.

Purpose of the Study:

• To develop and validate a comprehensive list of single, double, and triple comorbidity combinations (QCSs).
• To identify QCSs that more than double the odds of mortality.
• To define patients with at least one QCS as having multimorbidity (MM).

Main Methods:

• A cohort-based study was conducted using fee-for-service Medicare patients aged 65-85 undergoing general surgery.
• A matching validation study was employed.
• Data from 2009-2010 and 2011-2013 were analyzed, focusing on 30-day mortality.

Main Results:

• 576 Qualifying Comorbidity Sets (QCSs) were identified, each more than doubling mortality odds.
• In 2011, 36% of eligible patients had MM.
• Multimorbid patients exhibited a 7.0% mortality rate, significantly higher than non-multimorbid patients (1.6%).
• Patients with MM had an odds ratio of 1.90 compared to a mixed reference group and 3.72 compared to non-multimorbid patients.
• A significant difference in mortality rates (6.7% vs. 5.2%) was observed between low- and high-volume hospitals for matched MM patients.

Conclusions:

• A defined list of QCSs identified a substantial proportion of older surgical patients with significantly elevated mortality risk.
• These QCSs can serve as a tool to identify vulnerable patients.
• Understanding specific comorbidity combinations is crucial for predicting poor outcomes and tailoring interventions.