A systematic review of diagnostic test accuracy literature was conducted to inform Japanese decision-makers. To maximise the identification of relevant studies conducted in Japan, and potentially where reported in Japanese language, two Japanese databases (CiNii Articles and Ichushi-Web) were searched alongside core health technology assessment (HTA) databases (MEDLINE/Embase/Cochrane CENTRAL). Searching was performed in both English and Japanese language.

OBJECTIVES: To examine the effect on study identification of: i) including CiNii Articles and Ichushi-Web in addition to core HTA databases and, ii) searching in both English and Japanese language.

METHODS: The identification of studies included in our literature review was reanalysed for any difference in i) the number of studies identified by searching core HTA databases compared to CiNii Articles or Ichushi-Web and ii) the number of studies identified by searching in English or Japanese language.

RESULTS: Thirteen studies were identified. Of these, seven studies were identified and available uniquely by CiNii Articles (all seven) or Ichushi-Web (five of the seven). In addition, of these seven, five studies were identified uniquely by searching in English and two studies by searching in Japanese.

CONCLUSIONS: By searching CiNii Articles and Ichushi-Web in English and in Japanese, eligible studies were identified that would have been missed by relying on English-only searches of MEDLINE/Embase/Cochrane CENTRAL. This suggests that a systematic review of Japanese literature necessitates that Japanese-language and Japan-specific databases should be included.