Clinical risk factors for underlying gastrointestinal malignancy in iron deficiency anaemia: the IDIOM study.

Abstract

Objective : Ten percent of adults presenting with iron deficiency anaemia (IDA) have underlying cancer. This study was undertaken to assess whether five simple clinical parameters can usefully predict the likelihood of gastrointestinal (GI) malignancy on subsequent investigation of patients with IDA. Design : Retrospective observational study, with multivariable analysis of the predictive value of sex, age, haemoglobin concentration (Hb), mean red cell volume (MCV) and iron studies for the risk of underlying GI malignancy. Setting : District General Hospital IDA clinic. Patients : 720 adults with confirmed IDA. Results : Sex, age, and Hb were strongly associated with the risk of GI malignancy - the parsimonious model including only these variables yielded odds ratios of 4.0 (95% confidence interval (CI): 2.3, 7.0) for males compared to females; 3.3 (95% CI: 1.7, 6.4) for age > 70 years compared to ≤70 years; and 5.3 (95% CI: 2.4, 11.7) for an Hb of ≤91.4g/l compared to ≥111.5g/l. Combining these risk factors identified a sub-group (12% of the study population) at particularly low risk (<2% likelihood), and a second sub-group (16% of the study population) at especially high risk (>20% likelihood) of underlying GI malignancy. Conclusions : Three simple and objective clinical parameters can be combined to provide a clinically useful cancer risk stratification model for subjects with IDA. This may assist with patient counselling and the prioritization of investigational resources.