Clinical risk factors for underlying gastrointestinal malignancy in iron deficiency anaemia–prospective validation of the IDIOM score

Abstract

Objective: Ten percent of adults presenting with iron deficiency anaemia (IDA) have underlying cancer. This study was undertaken to prospectively validate the observation in a previous retrospective study that three simple clinical parameters can usefully predict the likelihood of gastrointestinal (GI) malignancy on investigation of patients with IDA, and to screen for other potential clinical predictors of risk.

Method: Observational study of a cohort of 643 subjects attending an IDA clinic at a District General Hospital between 2012 and 2015, with multivariable analysis of the predictive value of a series of clinical variables including sex, age and haemoglobin concentration ([Hb]) for underlying GI malignancy. Results: Analysis of the validation cohort data confirmed the original observation that sex, age, and Hb were associated with the risk of GI malignancy—the parsimonious model including only these variables yielded odds ratios of 1.9 (95% confidence interval (CI): 1.1, 3.3) for males vs. females; 1.6 (95% CI: 0.9, 2.9) for age >70 vs. ≤70 years; and 2.9 (95% CI:1.2, 6.9) for [Hb] <90.6 g/l vs. >112 g/l. Combining data from the observation and validation cohorts (total n = 1,363) identified sub-groups with cancer risks ranging from 0% to over 20%. No other predictive clinical variables were identified.

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 prioritisation of investigational resources.