Association between faecal occult bleeding and medicines prescribed for chronic disease: a data linkage study

Faecal haemoglobin concentrations are associated with all-cause mortality and cause of death in colorectal cancer screening

BACKGROUND

Colorectal cancer (CRC) screening reduces all-cause and CRC-related mortality. New research demonstrates that the faecal haemoglobin concentration (f-Hb) may indicate the presence of other serious diseases not related to CRC. We investigated the association between f-Hb, measured by a faecal immunochemical test (FIT), and both all-cause mortality and cause of death in a population-wide cohort of screening participants.

METHODS

Between 2014 and 2018, 1,262,165 participants submitted a FIT for the Danish CRC screening programme. We followed these participants, using the Danish CRC Screening Database and several other national registers on health and population, until December 31, 2018. We stratified participants by f-Hb and compared them using a Cox proportional hazards regression on all-cause mortality and cause of death reported as adjusted hazard ratios (aHRs). We adjusted for several covariates, including comorbidity, socioeconomic factors, demography and prescription medication.

RESULTS

We observed 21,847 deaths in the study period. Our multivariate analyses indicated an association relationship between increasing f-Hb and the risk of dying in the study period. This risk increased steadily from aHR 1.38 (95% CI: 1.32, 1.44) in those with a f-Hb of 7.1-11.9 μg Hb/g faeces to 2.20 (95% CI: 2.10, 2.30) in those with a f-Hb ≥60.0 μg Hb/g faeces, when compared to those with a f-Hb ≤7.0 μg Hb/g faeces. The pattern remained when excluding CRC from the analysis. Similar patterns were observed between incrementally increasing f-Hb and the risk of dying from respiratory disease, cardiovascular disease and cancers other than CRC. Furthermore, we observed an increased risk of dying from CRC with increasing f-Hb.

CONCLUSIONS

Our findings support the hypothesis that f-Hb may indicate an elevated risk of having chronic conditions if causes for the bleeding have not been identified. The mechanisms still need to be established, but f-Hb may be a potential biomarker for several non-CRC diseases.

Cause of Death, Mortality and Occult Blood in Colorectal Cancer Screening

Fecal hemoglobin (f-Hb) detected by the guaiac fecal occult blood test (gFOBT) may be associated with mortality and cause of death in colorectal cancer (CRC) screening participants. We investigated this association in a randomly selected population of 20,694 participants followed for 33 years. We followed participants from the start of the Hemoccult-II CRC trial in 1985-1986 until December 2018. Data on mortality, cause of death and covariates were retrieved using Danish national registers. We conducted multivariable Cox regressions with time-varying exposure, reporting results as crude and adjusted hazard ratios (aHRs). We identified 1766 patients with at least one positive gFOBT, 946 of whom died in the study period. Most gFOBT-positive participants (93.23%) died of diseases unrelated to CRC and showed higher non-CRC mortality than gFOBT-negative participants (aHR: 1.20, 95% CI 1.10-1.30). Positive gFOBT participants displayed a modest increase in all-cause (aHR: 1.28, 95% CI: 1.18-1.38), CRC (aHR: 4.07, 95% CI: 3.00-5.56), cardiovascular (aHR: 1.22, 95% CI: 1.07-1.39) and endocrine and hematological mortality (aHR: 1.58, 95% CI: 1.19-2.10). In conclusion, we observed an association between positive gFOBT, cause of death and mortality. The presence of f-Hb in the gFOBT might indicate the presence of systemic diseases.

Faecal haemoglobin concentrations in women and men diagnosed with colorectal cancer in a national screening programme

Objective

There is evidence that colorectal cancer screening using faecal haemoglobin is less effective in women than men. The faecal haemoglobin concentrations were therefore examined in women and men with screen-detected colorectal cancer.

Setting

Scottish Bowel Screening Programme, following the introduction of a faecal immunochemical test from November 2017, to March 2020.

Methods

Data were collated on faecal haemoglobin concentrations, pathological stage and anatomical site of the main lesion in participants who had colorectal cancer detected. The data in women and men were compared.

Results

For the faecal haemoglobin concentrations studied (>80 µg Hb/g faeces), the distributions indicated lower concentrations in women. Marked differences were found between women and men diagnosed with colorectal cancer. The median faecal haemoglobin concentration for women (n = 720) was 408 µg Hb/g faeces compared to 473 µg Hb/g faeces for men (n = 959) (p = 0.004) and 50.6% of the results were >400 µg Hb/g faeces in women; in men, this was 57.8%. The difference in faecal haemoglobin concentrations in women and men became less statistically significant as stage advanced from stages I–IV. For right-sided, left-sided and rectal colorectal cancer, a similar gender difference persisted in all sites. Differences in faecal haemoglobin between the genders were significant for left-sided cancers and stage I and approached significance for rectal cancers and stage II, but all sites and stages showed lower median faecal haemoglobin concentrations for women.

Conclusions

To minimise gender inequalities, faecal immunochemical test-based colorectal cancer screening programmes should evaluate a strategy of using different faecal haemoglobin concentration thresholds in women and men.

Faecal Haemoglobin Estimated by Faecal Immunochemical Tests-An Indicator of Systemic Inflammation with Real Clinical Potential

Multimorbidity is the major cause of ill-health and premature death in developed countries. The ability to identify individuals at risk of developing chronic disease, particularly multimorbidity, reliably, and simply, and to identify undiagnosed disorders, is vital to reducing the global burden of disease. This narrative review, the first of recent studies, demonstrates that raised faecal haemoglobin concentration (f-Hb) is associated with increased all-cause and cause-specific mortality and with longer-term conditions including diabetes, hypertension, cardiovascular disease, and psoriasis, and with probable intake of particulate matter. We and others have hypothesized that elevated f-Hb (measured using a faecal immunochemical test) has considerable potential to identify individuals at risk of, or who already have, early stage, undiagnosed chronic disease. If f-Hb does prove to be an effective biomarker for chronic disease and multimorbidity, individuals with detectable f-Hb, but without an obvious source of gastrointestinal blood loss, could benefit from further assessment and early intervention. To test this hypothesis rigorously, longitudinal data-linkage methodology is required linking colorectal cancer screening data, and data on patients presenting with lower gastrointestinal symptoms, with routinely collected health information.