Background: Since the number of polyarteritis nodosa (PAN) patients is small not only in Japan but also in the world, the characteristics of PAN have not been fully clarified and appropriate treatment has not been established.
Objectives: This study aimed to describe the epidemiological and clinical features and treatment of patients with PAN in Japan.
Methods: We used the database of the Ministry of Health, Labour and Welfare (MHLW) in 2013 and 2014. Data of 178 patients who fulfilled the diagnostic criteria by MHLW and had registered within a year after onset of PAN was analyzed.
Results: The analysis included 75 males and 103 females, with a mean age of 64.5 ± 20.3 years. PAN was diagnosed by clinical symptoms in 27.6% of the patients, 11.5% of the patients by pathological findings, and the rest of the patients by both. Pathological examination was performed in 71.3% of the patients, of whom 11.2% had evidence of necrotizing vasculitis of the small and medium arteries. As a systemic symptom, fever was observed in 55.2% of cases. As organ symptoms, muscle and joint symptoms (74.7%), skin symptoms (73.0%), neuropsychiatric symptoms (50.0%), respiratory symptoms (32.6%), and renal symptoms (19.7%) were common. Patients aged 65 or older had a higher rate of systemic, renal and respiratory symptoms, and lower rate of skin symptoms compared with the patients younger than 65. Patients with renal symptoms had a high prevalence of respiratory, cardiac and ocular symptoms, while those with respiratory symptoms had a high prevalence of systemic and cardiac symptoms. Laboratory findings showed that MPO- and/or p-ANCA positive rate was 30.5% and PR3- and/or c-ANCA positive rate was 11.0%. The Hepatitis B antigen positive rate was 3.9%. Angiography was performed in 20.7%, among which 27.0% were found to have multiple small aneurysms, wall irregularities and stenosis at the abdominal aortic branches. Glucocorticoids were used for treatment in all cases with an average maximum prednisolone dose of 32.5 mg/day. Concomitant immunosuppressants were used in 28.7%, half of which was cyclophosphamide. In other cases, azathioprine or methotrexate was used. Immunosuppressants have been used more frequently in patients with systemic symptoms and nasal and ear symptoms. Among the immunosuppressants, cyclophosphamide tends to be used for patients with higher CRP or patients with respiratory symptoms, and the maximum dose of glucocorticoids was significantly higher in patients who used cyclophosphamide compared to those who used other immunosuppressants.
Conclusion: PAN developed in middle-aged and elderly people and exhibited various clinical symptoms. We found that common symptoms varied with age, and treatment options were determined depending on the types of organ symptoms and severity. Hepatitis B virus infection was rare in patients with PAN in Japan.
Disclosure of Interests: : Mai Kawazoe: None declared, Toshihiro Nanki Grant/research support from: Chugai Pharmaceutical Co., Eisai Co., Ltd., Teijin Pharma Ltd., Eli Lilly Japan K.K., Bristol-Myers K.K., Ono Pharmaceutical Co., Ltd., Novartis Pharma K.K., Asahikasei Pharma Corp., Mitsubishi-Tanabe Pharma Co., Astellas Pharma Inc., Ayumi Pharmaceutical Co., Pfizer Japan Inc., Daiichi Sankyo Co., Ltd., Shionogi & Co., Ltd., Sanofi K.K., Nippon Kayaku Co., Ltd., Yutoku Pharmaceutical Ind. Co., Ltd., UCB Japan Co. Ltd., Nihon Pharmaceutical Co., Ltd., and Bayer Yakuhin, Ltd., Consultant of: UCB Japan Co., Ltd., Eisai Co., Ltd., and Chugai Pharmaceutical Co., Speakers bureau: Mitsubishi-Tanabe Pharma Co., Chugai Pharmaceutical Co., Eisai Co., Ltd., Astellas Pharma Inc., Janssen Pharmaceutical K.K., Ayumi Pharmaceutical Co., Pfizer Japan Inc., Asahikasei Pharma Corp., Sanofi K.K., Novartis Pharma K.K., Eli Lilly Japan K.K., Nippon Kayaku Co., Ltd., Teijin Pharma Ltd., Takeda Pharmaceutical Co., Nippon Boehringer Ingelheim Co., Ltd., and AbbVie GK., Noboru Hagino: None declared, Noriko Iketani: None declared, Satoshi Ito Speakers bureau: Abbvie,Eisai, Masanari Kodera: None declared, Naoko Nakano: None declared, Miki Suzuki: None declared, Shin-ya Kaname: None declared, masayoshi harigai Grant/research support from: AbbVie Japan GK, Ayumi Pharmaceutical Co., Bristol Myers Squibb Co., Ltd., Eisai Co., Ltd., Mitsubishi Tanabe Pharma Co., Nippon Kayaku Co., Ltd., and Teijin Pharma Ltd. MH has received speaker’s fee from AbbVie Japan GK, Ayumi Pharmaceutical Co., Boehringer Ingelheim Japan, Inc., Bristol Myers Squibb Co., Ltd., Chugai Pharmaceutical Co., Ltd., Eisai Co., Ltd., Eli Lilly Japan K.K., GlaxoSmithKline K.K., Kissei Pharmaceutical Co., Ltd., Oxford Immuotec, Pfizer Japan Inc., and Teijin Pharma Ltd. MH is a consultant for AbbVie, Boehringer-ingelheim, Kissei Pharmaceutical Co., Ltd. and Teijin Pharma.
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