Impact of faecal haemoglobin concentration on colorectal cancer mortality and all-cause death

Objective: To assess the effect of an incremental increase in faecal haemoglobin (f-Hb) concentration on colorectal cancer (CRC) mortality and all-cause death. Design: We conducted an observational study of cohorts over time based on two population-based CRC screening programmes. Setting: Two cities of Taiwan. Participants: 1233 individuals with CRC (217 prevalent cases and 1016 incident cases) and 2640 with colorectal adenoma (1246 prevalent cases and 1394 incident cases) found in the two cohorts of 59 767 and 125 976 apparently healthy individuals, aged 40 years and above, who had been invited to participate in screening since 2001 and 2003, respectively. Main outcome measures: Death from CRC and all-cause death ascertained by following up from the entire two cohorts over time until 2009. Results: The effect of an incremental increase in f-Hb on the risk for CRC mortality was noted, increasing from a slightly increased risk for the category of f-Hb of 20-49 ng Hb/mL (adjusted HR (aHR)=1.09;95% CI 0.68 to 1.75) to 11.67 (95% CI 7.71 to 17.66) for the group with f-Hb≥450 ng Hb/mL as compared with the group considered baseline with f-Hb of 1-19 ng Hb/mL (p<0.001). A similar but less marked increasing trend was found for all-cause mortality, aHR increasing from 1.15 (95% CI 1.07 to 1.24) for the group with f-Hb of 20-49 ng Hb/mL to 1.67 (95% CI 1.54 to 2.07) for the group with f-Hb≥450 ng Hb/mL. Conclusions: We substantiated the impacts of an incremental increase in f-Hb on the risk for death from CRC and all-cause death, consistently showing a significant gradient relationship. Both discoveries suggest that f-Hb may not only make contribution to facilitating individually tailored screening for CRC but also can be used as a significant predictor for life expectancy.