Poop Could Possibly Predict If an Ill Patient Is Likely to Die Within 30 Days

Your bowel movements reveal more than just the contents of last night’s dinner. New research that is both gruesome and dark, suggests your poop can tell experts how likely you are to die in the next month.

A team of medics writing in Science Advances developed the metabolic dysbiosis score (MDS), which uses 13 metabolites – chemicals that microbes produce – to predict mortality over a 30-day period.

The MDS may sound ominous. It may sound downright morbid. But it does offer a more life-affirming purpose. The hope is that one day, it could be used to help those in intensive care, offering a diagnostic tool and enabling doctors to identify patients at greater risk of death.

The human body is home to a vast ecosystem of microbiota (bacteria, viruses, fungi etcetera) that affect not only our health, but our behavior. Indeed, we carry as many as 100 trillion bacterial cells around with us each day – many of which are found in the gut.

In a healthy individual, the community of microbiota living in the digestive tract is balanced, with no one strain of microbe dominating. That is not the case when someone arrives at hospital in a critically ill state. Patients typically display lower diversity in gut microbiota and the microbiota present may be imbalanced – a state known as dysbiosis. It is this state that researchers based at the University of Chicago investigated.

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The team collected fecal samples from 196 critically ill patients admitted to intensive care for non-COVID respiratory failure or shock. They then analyzed the composition of the samples, specifically looking at what microorganisms were present (using shotgun metagenomic sequencing) and the concentrations of metabolites (using mass spectrometry).

Neither the microbial compositions nor the individual fecal metabolite concentrations by themselves were associated with 30-day mortality after admission to the ICU. However, the researchers developed the MDS based on concentrations of 13 metabolites that were associated. The thirteen metabolites included short-chain fatty acids (SCFAs), bile acids, and tryptophan metabolites, all of which are involved in physiological processes “with plausible relevance for survival,” the researchers wrote.

Research was built on data collected from 147 (75 percent) patients (training cohort) and tested on the remaining 49 (25 percent) patients (validation cohort). Overall, 30-day mortality of the training cohort was 30.6 percent, meaning 69.4 percent survived. The researchers note no difference in the age, sex, race, and overall comorbidity burden between survivors and non-survivors, but did observe that non-survivors were more likely to have metastatic solid tumors and/or sepsis. Moreover, the MDS scores of non-survivors were consistently higher than those of survivors.

Indeed, when only fecal samples collected within the first 3 days of ICU admission (65 percent of patients) were included, the MDS correctly predicted mortality rates 84 percent of the time. To break it down further, the score demonstrated a sensitivity (or true positive rate) of 88 percent. This means it accurately predicted 88 percent of non-survivors. It had a specificity score (or true negative rate) of 75 percent, meaning it successfully predicted 75 percent of survivors.

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While future research is needed to validate the results and confirm whether or not it can be applied to all patients entering intensive care, the researchers hope the MDS will pave the way for new diagnosis and treatment routes in the future.

“The MDS may serve as a biomarker to identify patients who might benefit from correction of fecal metabolic dysbiosis,” the researchers wrote. “Moreover, we identify fecal metabolites that may be a treatable trait to improve the survival of critically ill patients.”

This article is not offering medical advice and should be used for informational purposes only.

Our writers at Discovermagazine.com use peer-reviewed studies and high-quality sources for our articles, and our editors review for scientific accuracy and editorial standards. Review the sources used below for this article:

• Science Advances. Fecal metabolite profiling identifies critically ill patients with increased 30-day mortality

Rosie McCall is a freelance writer living in London. She has covered science and health topics for publications, including IFLScience, Newsweek, and Health.