Treatment patterns reflect delayed diagnosis and suboptimal adherence.

Background & Rationale

Iron deficiency (ID) and iron deficiency anaemia (IDA) represent prevalent global health concerns, frequently associated with chronic inflammatory conditions such as inflammatory bowel disease. Accurate epidemiological data regarding ID and IDA incidence, progression, and treatment patterns are crucial for optimising patient care. Existing data often rely on cross-sectional analyses or limited patient cohorts. This study aimed to characterise the epidemiology and treatment landscape of ID and IDA using real-world longitudinal data from a large German health claims database, providing insights into diagnostic delays and treatment adherence. Understanding current practice patterns is important for identifying potential areas for improvement in the management of these conditions.

Study Design

This retrospective cohort study utilised longitudinal claims data from the IQVIA disease analytics database, covering approximately 7.5 million individuals insured under statutory health insurance in Germany. Data spanned from January 2014 to December 2022. Patients were included if they had at least one diagnosis code indicating ID (ICD-10 code D50) or IDA (ICD-10 code D50.0) during the study period. Researchers identified incident cases of ID and IDA. The study tracked treatment patterns including iron supplementation (oral and intravenous) and erythropoiesis-stimulating agents (ESAs) following diagnosis. Analyses included descriptive statistics and time-to-event analyses.

Patient Population

The study cohort comprised 235,646 individuals diagnosed with either ID or IDA, with 169,685 (72%) identified as having ID and 65,961 (28%) diagnosed with IDA. The mean age of the overall cohort was 58.7 years, with 57.3% being female. Approximately 14.8% of the cohort had a pre-existing diagnosis of inflammatory bowel disease. The median time from first identified ID code to a diagnosis of IDA was 289 days. The predominant comorbidities observed included anaemia of chronic disease, gastrointestinal bleeding, and renal impairment.

Key Findings

During the observation period, the incidence rate of ID was 1,789 per 100,000 person-years, while the incidence rate of IDA was 565 per 100,000 person-years. Following a diagnosis of ID, 49.2% of patients received oral iron supplementation, while 13.2% received intravenous iron. For patients diagnosed with IDA, the rates of oral and intravenous iron supplementation were 58.6% and 25.6% respectively.

The median duration of oral iron treatment was 180 days. A substantial proportion of patients discontinued oral iron within the first 90 days; 34.5%. Among patients receiving intravenous iron, the median number of infusions was three. Only 1.1% of patients across both ID and IDA groups received ESAs.

Of those diagnosed with ID, 16.8% progressed to IDA within one year; within two years, this increased to 28.5%. Patients with a pre-existing diagnosis of inflammatory bowel disease had a higher risk of progression from ID to IDA than those without (hazard ratio 1.41).

Discussion

This large-scale, real-world analysis highlights significant delays in the diagnosis and treatment of ID and IDA within the German healthcare system. The considerable time between initial diagnosis of ID and progression to IDA suggests opportunities for earlier intervention and increased awareness. Relatively low rates of intravenous iron utilisation, especially given the potential benefits for patients with intolerance or poor response to oral iron, were noted. The limited use of ESAs, even in those with anaemia, requires further investigation.

The study observed a concerning level of non-adherence to oral iron therapy, with a significant proportion of patients discontinuing treatment within 90 days. This likely contributes to the observed progression from ID to IDA. Greater emphasis on adherence support strategies may be beneficial. The higher risk of progression to IDA in patients with pre-existing inflammatory bowel disease reinforces the need for proactive monitoring and management within this specific patient group.

Authors’ Conclusions

The authors concluded that this study demonstrates the substantial burden of ID and IDA within the German healthcare system, with prolonged diagnostic delays and suboptimal treatment adherence. They suggest the findings underscore the need for enhanced diagnostic pathways, improved treatment strategies, and greater focus on patient adherence to optimise the management of these conditions, particularly in patients with comorbidities such as inflammatory bowel disease. The study also highlights the need for further research to understand the reasons for low ESA utilisation.

Reference

Manz KC, Murphy D, Stavenow F, Astorquiza LGC, Cengia A, Višković V, Höer A, Mocek A. Epidemiology and treatment of patients with iron deficiency and iron deficiency anemia: a study on longitudinal German health claims data. BMC public health. 2025;25(1):634. DOI: 10.1186/s12889-025-24730-9.