Use of Fecal Immunochemical Testing in Acute Patient Care in a Safety Net Hospital System

Colorectal cancer (CRC) is the second leading cause of cancer-related mortality in the United States. It is estimated that in 2020, 147,950 individuals will be diagnosed with invasive CRC and 53,200 will die from it.¹ While the overall incidence has been declining for decades, it is rising in young adults.^2–4 Screening using direct visualization procedures (colonoscopy and sigmoidoscopy) and stool-based tests has been demonstrated to improve detection of precancerous and early cancerous lesions, thereby reducing CRC mortality.⁵ However, screening rates in the United States are suboptimal, with only 68.8% of adults aged 50 to 75 years screened according to guidelines in 2018.⁶Stool-based testing is a well-established and validated screening measure for CRC in asymptomatic individuals at average risk. Its widespread use in this population has been shown to cost-effectively screen for CRC among adults 50 years of age and older.^5,7 Presently, the 2 most commonly used stool-based assays in the US health care system are guaiac-based tests (guaiac fecal occult blood test [gFOBT], Hemoccult) and fecal immunochemical tests (FITs, immunochemical fecal occult blood test [iFOBT]). FITs, which rely on the detection of globin in stool, have increasingly replaced guaiac-based tests in many health care systems. The frequency of FIT use is growing, in part, due to its lack of restrictions relative to traditional guaiac-based methods. FITs require a single stool sample and are not affected by foods with peroxidase activity; also, the predictive value of their results is not skewed by medications that can cause clinically insignificant GI bleeding (GIB), such as aspirin.⁸ Moreover, there is a growing body of evidence that FIT has improved sensitivity and specificity over guaiac-based tests in the detection of CRC and advanced adenomas.^9-12

Despite the exclusive validation of FOBTs for use in CRC screening, studies have demonstrated that they are commonly used for a multitude of additional indications in emergency department (ED) and inpatient settings, most aimed at detecting or confirming GI blood loss. This may lead to inappropriate patient management, including the receipt of unnecessary follow-up procedures, which can incur significant costs to the patient and the health system.^13-19 These costs may be particularly burdensome in safety net health systems (ie, those that offer access to care regardless of the patient’s ability to pay), which serve a large proportion of socioeconomically disadvantaged individuals in the United States.^20,21 To our knowledge, no published study to date has specifically investigated the role of FIT in acute patient management.

This study characterizes the use of FIT in acute patient care within a large, urban, safety net health care system. Through a retrospective review of administrative data and patient charts, we evaluated FIT use prevalence, indications, and patient outcomes in the ED and inpatient settings.