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Occult blood in feces linked to more than just colorectal cancer mortality

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Occult blood in feces might reflect on multiple health issues

This study makes the “provocative” suggestion that occult blood in feces may reveal more than was previously thought, Uri Ladabaum, MD, of Stanford (Calif.) University wrote in a commentary.

“If the eye is the window to the soul, is a fecal test the window to general health?” he asked in the commentary appearing in the journal Gut.

The initial surprise that a positive guaiac fecal occult blood test is associated with more than just colorectal cancer (CRC) mortality might be tempered, however, after considering that risk factors for many diseases are integrated, Dr. Ladabaum said. In other words, risk factors for CRC, such as obesity, inactivity, poor diet, or diabetes, may be at least partly responsible for the effects on non-CRC death seen in this study, although authors did try to control for some of those factors in their analyses, he said.

Whether a positive guaiac fecal occult blood test should prompt any additional interventions or alerts to the patient remains a question to be resolved, according to Dr. Ladabaum. “For now, I believe that our enthusiasm for the established CRC screening methods should not be affected, and that the focus after an abnormal fecal occult blood test should be to ensure prompt delivery of a follow-up colonoscopy,” he wrote.

Dr. Ladabaum is with the division of gastroenterology and hepatology and the department of medicine at Stanford (Calif.) University. These comments are from his commentary in Gut (2018. doi: 10.1136/gutjnl-2018-316762). Dr. Ladabaum reported being a consultant for Medtronic and Motus and an advisory board member of Universal Dx.


 

FROM GUT

Occult blood in the feces was associated not only with colorectal cancer mortality, but also mortality from other causes, Scottish investigators have reported based on findings of a large, retrospective study.

A positive guaiac fecal occult blood test (gFOBT) was associated with all-cause mortality excluding colorectal cancer in the study, which included data on individuals screened in Scotland during 2000-2016.

Positive gFOBT results were also associated with other disease-specific mortality outcomes, including circulatory, respiratory, and digestive disease.

The findings might have important clinical implications beyond colorectal cancer if corroborated by prospective studies in the future, wrote investigator Gillian Libby of the Bowel Screening Research Unit at Ninewells Hospital and Medical School, Dundee, Scotland, and coinvestigators.

“If hemoglobin in feces is a risk factor for all-cause death, it may have the potential as a modifiable biomarker that could be used to assess the efficacy of both lifestyle and drug interventions to reduce the risk of premature mortality,” investigators wrote in a report on the study released in the journal Gut.

The investigators linked gFOBT results for 133,921 screened individuals who ranged in age from 50 to 74 years to mortality data from the National Records of Scotland Database.

As expected, individuals with positive results had a considerably higher risk of death not only from colorectal cancer (hazard ratio, 7.79; 95% confidence interval, 6.13-9.89; P less than .0001) but also for noncolorectal cancer causes combined (HR, 1.58; 95% CI, 1.45-1.73; P less than .0001) after adjustment for age, sex, deprivation, and prescribed medicines.

The higher risk of death held for mortality related to circulatory, respiratory, digestive, endocrine, neuropsychological, and other causes, as reported.

“It is clear from this study that, in the Scottish population, the presence of hemoglobin in the faeces as detected by gFOBT is associated with a number of non-CRC causes of death,” investigators wrote.

These results do corroborate those of one other recent study in Taiwan that showed a relationship between positive gFOBT tests and all-cause mortality.

“In contrast to the Taiwanese study, we were able to examine this association broken down by disease categories and adjusting for confounding factors,” they noted in their discussion of the results.

Funding for the study came from the Chief Scientist Office of the Scottish Government Health Directorates. One study coauthor reported a consultancy with Immunostics, and no other disclosures were reported.

SOURCE: Libby G et al. Gut. 2018. doi: 10.1136/gutjnl-2018-316483.

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