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

Modelling the episodes of care for iron deficiency anemia patients in a secondary-care center using continuous-time multistate Markov chain

BACKGROUND

Despite the high prevalence of gastro-intestinal (GI) cancer in iron deficiency anemia (IDA), some IDA patients do not complete all the necessary GI investigations at the initial referral. As a result, existing cancers are diagnosed at a later referral with worse prognosis. The potential to detect GI cancer early depends on minimizing the delay time spent between the two consecutive referrals, where a patient did not complete investigations at the first referral, but at the second is diagnosed with positive GI cancer. This retrospective longitudinal study aims to highlight the proper methods to model these referrals.

METHODS

Using anonymized data of 168 episodes of care for IDA patients at an IDA clinic in a secondary care setting, continuous-time multi-state Markov chain is employed to determine the transition rates among three observed states for IDA patients at the IDA clinic, "incomplete investigations," "negative GI cancer," and "positive GI cancer" and to estimate the delay time.

RESULTS

Once in the state of incomplete investigations, an estimated mean delay time of 3.1 years (95% CI: 1.2, 5) is spent before being diagnosed with positive GI cancer. The probability that a "positive GI diagnosis" is next after the state of "incomplete investigation" is 17%, compared with 11% when it is followed in the state of negative GI cancer. Defining the survival as the event of not being in the state of "positive GI cancer," the survival rate of IDA patients with negative GI cancer is always higher than those with incomplete investigations. Finally, being diagnosed with positive GI cancer is always preceded by the prediction of being considered "very high risk" at the earlier visit.

CONCLUSION

A baseline model was proposed to represent episodes of care for IDA patients at a secondary care center. Preliminary results highlight the importance of completing the GI investigations, especially in IDA patients, who are at high risk of GI cancer and fit to go through the investigations.

Broad external validation of a multivariable risk prediction model for gastrointestinal malignancy in iron deficiency anaemia

BACKGROUND

Using two large datasets from Dorset, we previously reported an internally validated multivariable risk model for predicting the risk of GI malignancy in IDA-the IDIOM score. The aim of this retrospective observational study was to validate the IDIOM model using two independent external datasets.

METHODS

The external validation datasets were collected, in a secondary care setting, by different investigators from cohorts in Oxford and Sheffield derived under different circumstances, comprising 1117 and 474 patients with confirmed IDA respectively. The data were anonymised prior to analysis. The predictive performance of the original model was evaluated by estimating measures of calibration, discrimination and clinical utility using the validation datasets.

RESULTS

The discrimination of the original model using the external validation data was 70% (95% CI 65, 75) for the Oxford dataset and 70% (95% CI 61, 79) for the Sheffield dataset. The analysis of mean, weak, flexible and across the risk groups' calibration showed no tendency for under or over-estimated risks in the combined validation data. Decision curve analysis demonstrated the clinical value of the IDIOM model with a net benefit that is higher than 'investigate all' and 'investigate no-one' strategies up to a threshold of 18% in the combined validation data, using a risk cut-off of around 1.2% to categorise patients into the very low risk group showed that none of the patients stratified in this risk group proved to have GI cancer on investigation in the validation datasets.

CONCLUSION

This external validation exercise has shown promising results for the IDIOM model in predicting the risk of underlying GI malignancy in independent IDA datasets collected in different clinical settings.

The Value of Quantitative Faecal Immunochemical Testing as a Prioritisation Tool for the Endoscopic Investigation of Patients With Iron Deficiency

Difficulty in providing endoscopy for patients with iron deficiency anaemia (IDA) during the COVID-19 pandemic has highlighted the requirement for a prioritisation tool. We aimed to test the validity of qFIT as a prioritisation tool in patients with iron deficiency and its ability to identify patients with advanced neoplastic lesions (ANLs). Data collected from patients referred with biochemically proven iron deficiency (ferritin ≤ 15 μg/L) and synchronous qFIT who underwent full gastrointestinal investigation within NHS Greater Glasgow and Clyde was analysed retrospectively. Patients who did not undergo full investigation, defined as gastroscopy and colonoscopy or CT colonography, were excluded. ANLs were defined as defined as upper GI cancer, colorectal adenoma ≥ 1 cm or colorectal cancer. Area under the curve (AUC) analysis was performed on qFIT results and outcome, defined as the presence of an ANL. AUC analysis guided cut-off scores for qFIT. Patients with a qFIT of <10, 10–200, >200, were allocated a score of 1, 2, and 3, respectively. A total of 575 patients met criteria for inclusion into the study. Overall, qFIT results strongly predicted the presence of ANLs (AUC 0.87, CI 0.81–0.92; P < 0.001). The prevalence of ANLs in patients with scores 1–3 was 1.2, 13.5, and 38.9% respectfully. When controlled for other significant variables, patients with a higher qFIT score were statistically more likely to have an ANL (qFIT score = 2; OR 12.8; P < 0.001, qFIT score = 3, OR 50.0; P < 0.001). A negative qFIT had a high NPV for the presence of ANLs (98.8%, CI 97.0–99.5%). These results strongly suggest that qFIT has validity as a prioritisation tool in patients with iron deficiency; both allowing for a more informed decision of investigation of patients with very low risk of malignancy, and in identifying higher risk patients who may benefit from more urgent endoscopy.

Iron deficiency: a modern primer to diagnosis and management

PURPOSE OF REVIEW

Iron deficiency with anemia (IDA) and without anemia remain a diagnostic and management challenge. Iron deficiency has a broad spectrum of causes, including gastrointestinal malignancy. The purpose of this review is to summarize the value and limitations of current methods to diagnose iron deficiency and underline the relevance of contemporaneous evidence to guide the pretest probability of gastrointestinal disease.

RECENT FINDINGS

A number of biomarkers for iron deficiency exist, and all have their caveats. Serum ferritin remains the most pragmatic means of diagnosing iron deficiency. Hepcidin holds future promise as a marker of iron status during inflammatory states. Men and postmenopausal women with IDA have the highest overall prevalence of gastrointestinal malignancy (∼11%), while premenopausal women with IDA (<1.5%) and those with iron deficiency without anemia (<0.5%) have a very low risk. Noninvasive investigation with fecal immunochemical test and fecal calprotectin hold promise to guide further investigations in lower risk groups.

SUMMARY

Confirmation of iron deficiency remains a challenge. Appropriate risk stratification is the key to guiding judicious gastrointestinal investigation. Use of noninvasive tests may play an important role in lower risk groups. Risk prediction tools applicable to relevant populations are required.

The dedicated iron deficiency anaemia clinic: a 15-year experience

OBJECTIVE

To report our cumulative experience from a dedicated iron deficiency anaemia (IDA) clinic over the last 15 years-with particular emphasis on referral rate, uptake of investigation, impact on endoscopy services, diagnostic yield of gastrointestinal (GI) investigation and the issue of recurrent IDA.

METHOD

A series of analyses of a register of 2808 referrals to the Poole IDA clinic between 2004 and 2018.

RESULTS

The study population of 2808 had a sex ratio of 1.9 (female/male ratio) and a median age of 72 years (IQR: 60-79). A rising referral rate over the study period appears to be plateauing at around 2 cases per 1000 population per annum. On the basis of a snapshot audit, investigation of IDA may now account for over 20% of all diagnostic endoscopies.Overall, 86% of cases underwent examination of the upper and lower GI tract. Significant GI pathology was identified in 27% of the investigated cohort. Adenocarcinoma of the upper or lower GI tract was found in 8.3%, the majority in the right colon. The prevalence of recurrent IDA was estimated at 12.4%, and the results of investigation of this subgroup are reported.

CONCLUSION

Unexplained IDA is common, particularly in those over 60 years, and may be the first indication of underlying GI malignancy in over 8% of cases. Unresolved challenges include accommodating the resulting endoscopy workload, establishing a risk/benefit ratio for investigating those with major comorbidities and the management of recurrent IDA.

Refinement and validation of the IDIOM score for predicting the risk of gastrointestinal cancer in iron deficiency anaemia

OBJECTIVE

To refine and validate a model for predicting the risk of gastrointestinal (GI) cancer in iron deficiency anaemia (IDA) and to develop an app to facilitate use in clinical practice.

DESIGN

Three elements: (1) analysis of a dataset of 2390 cases of IDA to validate the predictive value of age, sex, blood haemoglobin concentration (Hb), mean cell volume (MCV) and iron studies on the probability of underlying GI cancer; (2) a pilot study of the benefit of adding faecal immunochemical testing (FIT) into the model; and (3) development of an app based on the model.

RESULTS

Age, sex and Hb were all strong, independent predictors of the risk of GI cancer, with ORs (95% CI) of 1.05 per year (1.03 to 1.07, p<0.00001), 2.86 for men (2.03 to 4.06, p<0.00001) and 1.03 for each g/L reduction in Hb (1.01 to 1.04, p<0.0001) respectively. An association with MCV was also revealed, with an OR of 1.03 for each fl reduction (1.01 to 1.05, p<0.02). The model was confirmed to be robust by an internal validation exercise. In the pilot study of high-risk cases, FIT was also predictive of GI cancer (OR 6.6, 95% CI 1.6 to 51.8), but the sensitivity was low at 23.5% (95% CI 6.8% to 49.9%). An app based on the model was developed.

CONCLUSION

This predictive model may help rationalise the use of investigational resources in IDA, by fast-tracking high-risk cases and, with appropriate safeguards, avoiding invasive investigation altogether in those at ultra-low predicted risk.

A comprehensive evaluation of the gastrointestinal tract in iron-deficiency anemia with predefined hemoglobin below 9mg/dL: A prospective cohort study

BACKGROUND

Anemia is defined as hemoglobin below the cutoff of normal in studies examining the gastrointestinal (GI) tract in iron-deficiency anemia (IDA). Although the risk of GI cancer (GIC) increases as hemoglobin decreases, guidelines do not usually recommend hemoglobin thresholds for IDA investigation.

METHODS

To elucidate whether underlying GI disorders explain the different hemoglobin values and clinical outcomes observed initially in IDA patients referred for GI workup, we prospectively investigated the diagnostic yield of a thorough GI examination in consecutive IDA adults with predefined hemoglobin <9g/dL and no extraintestinal bleeding.

RESULTS

4552 patients were enrolled over 10 years. 96% of 4038 GI lesions were consistent with occult bleeding disorders and 4% with non-bleeding disorders. Predominant bleeding disorders included upper GI ulcerative/erosive lesions (51%), GIC (15%), and angiodysplasias (12%). Diffuse angiodysplasias (45% of angiodysplasias) and GIC showed the lowest hemoglobin values (6.3 [1.5] and 6.4 [1.3]g/dL, respectively). While the spread (diffuse vs. localized) and number (<3 vs. ≥3) of angiodysplasias correlated with the degree of anemia, hemoglobin values were lower in GIC with vs. without ulcerated/friable lesions (6.0 [1.1] vs. 7.0 [1.2]g/dL, P<0.001).

CONCLUSION

Not only GIC but also diffuse angiodysplasias caused the most severe anemia in IDA with predefined hemoglobin values <9g/dL.

The development of a nurse-led iron deficiency anaemia service in a district general hospital

OBJECTIVE

To improve the quality of care provided to patients with iron deficiency anaemia (IDA).

DESIGN

Service development.

SETTING

District General Hospital.

PATIENTS

Adults with IDA.

MAIN OUTCOME MEASURES

Descriptive report of the practicalities and benefits of establishing an IDA clinic.

CONCLUSIONS

The IDA clinic is a novel service development which enhances the management of patients with this common condition, by facilitating prompt confirmation of the diagnosis, replacement therapy and investigation for serious underlying pathology, in particular gastrointestinal malignancy.