Comprehensive Analysis of Iron Deficiency Anemia and Its Related Disorders in Premenopausal Women Based on a Propensity Score Matching Case Control Study Using National Health Insurance Service Database in Korea

Abstract

Background: Menorrhagia is a common cause of iron deficiency anemia (IDA) in premenopausal women. However, the effects of menorrhagia on IDA in premenopausal women have been underestimated compared to those on other IDA-related disorders (IRDs) such as gastrointestinal malignancies (GIMs). To better understand the relationship between menorrhagia and IDA in premenopausal women, we analyzed the National Health Insurance Service-National Health Information Database (NHIS-NHID). Methods: From 2005 to 2008, data about women between the age of 20 and 59 years were extracted from the NHIS-NHID to create a propensity score-matched case (IDA) and control group. The annual incidence of IDA was calculated per age group. A 10-year follow up of the study population was determined to detect IRDs in case and control groups. We compared the risk of detection (ROD) of IRDs, including GIM and gynecological disorders associated with menorrhagia - leiomyoma of uterus (LM) and adenomyosis (AM), in the case and the control group. Results: From 2005 to 2008, women diagnosed with IDA (n = 535,249) and healthy women as a control group (n = 1,070,498) were identified from the NHIS-NHID. The annual incidence of IDA was 767.4 (2005), 948.7 (2006), 981.6 (2007), and 897.7 (2008) per 100,000 women. The age distribution of IDA was similar each year; IDA was common in women aged 30–39 years (36–37%) and 40–49 years (30–32%), and its incidence was significantly decreased in women aged 50–59 years (< 10%). The ROD of IRDs were significantly higher in the IDA group than in the control group (LM: 20.8% vs. 6.9%, AM: 5.6% vs. 1.6%, and GIM: 2.6% vs. 0.7%). The corresponding hazard ratios were 3.89 (95% confidence interval [CI], 3.85–3.93) for LM, 4.99 (95% CI, 4.90–5.09) for AM, and 3.43 (95% CI, 3.32–3.55) for GIM. The ROD of the IRDs varied; the ROD of LM in the IDA group increased with age and decreased in the age group 50–59 years. AM was more frequently detected in women with IDA aged 30–39 years and less in women older than 40 years. The frequency of GIM increased with age. Conclusion: In this study, we found that the gynecologic disease is the main cause of IDA in premenopausal women. Gynecological evaluations should be performed more actively in the clinic to prevent and control IDA and IRDs.