Burden of Four Curable Sexually Transmitted Infections in Japan and The Research Gaps: A Systematic Literature Review

目的：系統的文献レビューで，4種のSTIにおける日本での疾病負荷研究をマッピングし，エビデンスギャップの特定を目的とした． 方法：青年期以上の対象性感染症をもつ患者を対象にPubMedと医中誌で検索を行った．アウトカムには，疫学，治療，経済的，および人道的負荷が含まれた． 結果：疫学（n = 31），治療（n = 13），および経済的負荷（n = 8）を報告する48件の文献が特定された．人道的負荷に関する研究は特定されなかった．最も研究された性感染症としては，クラミジア（n = 28）と淋病（n = 27）であった．全国的サーベイランスにおける定点調査においてクラミジアと淋病が継続的に減少していることが示された．ただし，調査定点の非代表性も示唆された．有病率，重複感染，および無症候性の発生率に関する報告では，併存疾患や性別等の人口特性に依存し，幅広い発生率が明らかになった．経済的および人道的負荷とセックスワーカーに関するデータは希少であった． 考察：本研究は，患者の脆弱性，治療へのアクセス，無症候性等の患者特性の考慮，抗菌薬耐性監視の強化，データ不足を補足するさらなる研究の必要性を示した．Purpose: We aimed to map and synthesize evidence on the burden of four curable STIs (chlamydia, gonorrhea, syphilis, and trichomonas) in Japan using a systematic literature review and to identify the research gaps. Methods: According to the pre-defined criteria, PubMed and ICHUSHI databases were searched for studies conducted in Japan. Target populations included patients with at least one of the curable STIs of interest who were adolescents or older. Target outcomes included epidemiology, treatment, economic, and humanistic burdens. Results: A screening of 935 references and complementary hand-search identified 48 references reporting epidemiological (n=31), treatment (n=13), and economic burdens (n=8). No relevant studies assessing humanistic burdens were identified. Chlamydia was the most studied STI (n=28), followed by gonorrhea (n=27). The national surveillance showed continuous decreases in notifications of chlamydia and gonorrhea by sentinel sites over the years; however, potential unrepresentativeness of the sentinel sites was suggested based on data from some studies. Reports on prevalence, co-infection, and asymptomatic rates revealed a wide range of rates that were highly dependent on the population characteristics such as comorbid status and gender. The recent rise of decreased in vitro gonorrhea susceptibility to ceftriaxone was observed in several studies. Data on economic and humanistic burdens and on commercial sex workers were limited. Conclusion: The overall mapped evidence underscored the importance of further considering variability in patientsʼ characteristics such as vulnerability, treatment accessibility, and asymptomatic rates, enhancement of antimicrobial resistance surveillance systems, and fulfilment of research gaps due to data scarcity