Therapeutics and Clinical Risk Management (Sep 2017)
Increased risk of pernicious anemia following scabies: a nationwide population-based matched-cohort study
Abstract
Jui-Ming Liu,1–3,* Ren-Jun Hsu,3–5,* Fung-Wei Chang,6 Feng-Hsiang Chiu,7,8 Chia-Lun Yeh,1 Chun-Fa Huang,9,10 Shu-Ting Chang,11 Hung-Chang Lee,12 Hsin Chi,12,13 Chien-Yu Lin14,15 1Division of Urology, Department of Surgery, Taoyuan General Hospital, Ministry of Health and Welfare, Taoyuan, 2Department of Medicine, National Yang-Ming University, 3Graduate Institute of Life Sciences, 4Department of Pathology and Graduate Institute of Pathology and Parasitology, the Tri-Service General Hospital, National Defense Medical Center, 5Biobank Management Center of the Tri-Service General Hospital, 6Department of Obstetrics and Gynecology, Tri-Service General Hospital, National Defense Medical Center, Taipei, 7Department of Emergency Medicine, Shuang Ho Hospital, Taipei Medical University, New Taipei City, Taiwan; 8Superintendent office, Lihuili Eastern Hospital, Ningbo, Zhejiang province, People’s Republic of China; 9School of Chinese Medicine, College of Chinese Medicine, China Medical University, 10Department of Nursing, College of Medical and Health Science, Asia University, Taichung City, 11Department of Gastroenterology, BinKun Women’s and Children’s Hospital, Taoyuan City, 12Department of Infectious Disease, MacKay Children’s Hospital, Taipei, 13Department of Medicine, MacKay Medical College, New Taipei city, 14Department of Pediatrics and Infectious Disease, Hsinchu MacKay Memorial Hospital, Hsinchu City, Taiwan; 15Division of Infection and Pathway Medicine, College of Medicine and Veterinary Medicine, The University of Edinburgh, Scotland, UK *These authors contributed equally to this work Objectives: Scabies is a common and annoying disorder. Pernicious anemia (PA) is a serious disease which, when untreated, leads to death. Mounting evidence suggests that immune-mediated inflammatory processes play a role in the pathophysiology of both diseases. The relationship between these two diseases has not been investigated. We conducted this study to explore the potential relationship between scabies and PA.Materials and methods: This nationwide, population-based study was conducted using the National Health Insurance Research Database of Taiwan. In total, 5,407 patients with scabies were identified as a study group and 20,089 matched patients were randomly selected as a control group. We tracked patients in both groups for a 7-year period to identify the incidence of PA. The demographic characteristics and comorbidities of the patients were analyzed, and Cox proportional hazards regression was used to calculate the hazard ratios for PA.Results: Of the 25,496 patients in this study, 183 (0.7%) patients with newly diagnosed PA were identified during the 7-year follow-up period; 71 of 5,407 (1.3%) from the scabies group and 112 of 20,089 (0.6%) from the control group. Patients with scabies had a higher risk of subsequent PA, with a crude hazard ratio of 2.368. After adjusting for covariates, the adjusted hazard ratio was 1.51 (95% confidence interval: 1.09–2.08).Conclusion: This study demonstrated an increased risk of PA (adjusted hazard ratio 1.51) among patients with scabies. Immune-mediated inflammatory processes may contribute to this association. Further studies are warranted to investigate the entire pathological mechanisms between these two diseases. Physicians should pay attention to patients with history of scabies presented with anemia. Further confirmative tests of PA may contribute to correct diagnosis and initiation of vitamin B12 supplement. Keywords: scabies, pernicious anemia, National Health Insurance Research Database, autoimmune gastritis, vitamin B12 deficiency, cobalamin
