An assessment of the characteristics and quality of diagnostic accuracy studies for positron emission tomography conducted in Japan: a systematic review

Shuhei Nomura; Akinori Hisashige; Daisuke Yoneoka; Mikiko Kanda; Karin Miyamoto; Miwako Segawa; Erika Ota; Kenji Shibuya

doi:10.1186/s13550-015-0084-4

An assessment of the characteristics and quality of diagnostic accuracy studies for positron emission tomography conducted in Japan: a systematic review

EJNMMI Res. 2015 Feb 19:5:6. doi: 10.1186/s13550-015-0084-4. eCollection 2015.

Authors

Shuhei Nomura¹, Akinori Hisashige², Daisuke Yoneoka³, Mikiko Kanda³, Karin Miyamoto³, Miwako Segawa³, Erika Ota³, Kenji Shibuya³

Affiliations

¹ Department of Global Health Policy, Graduate School of Medicine, The University of Tokyo, 7-3-1 Hongo, Bunkyo-ku, Tokyo 113-0033 Japan ; Present affiliation: Department of Epidemiology and Biostatistics, School of Public Health, Imperial College London, Norfolk Place, London, W2 1PG UK.
² Institute of Healthcare Technology Assessment, 2-24-10, Shomachi, Tokushima, 770-0044 Japan.
³ Department of Global Health Policy, Graduate School of Medicine, The University of Tokyo, 7-3-1 Hongo, Bunkyo-ku, Tokyo 113-0033 Japan.

Abstract

Background: Systematic evaluations of the diagnostic accuracy of positron emission tomography (PET) imaging have been widely conducted in many countries. Although Japan's total number of PET units is the second highest in the world, very limited effort has been made to systematically assess the methodological quality of PET studies in Japan. We performed a systematic review to assess the characteristics and quality of PET diagnostic accuracy studies conducted in Japan and to analyze the factors related to their quality.

Methods: All PET studies conducted in Japan were identified using MEDLINE and the Japan Medical Abstract Society Database. The characteristics of the Japanese studies were examined and their methodological quality evaluated by the standardized quality assessment of diagnostic accuracy studies (QUADAS) tool. We compared the quality of studies indexed in MEDLINE with non-indexed studies, followed by a comparison of the studies' conclusions with those of international health technology assessment (HTA) reports.

Results: A total of 138 studies were identified. Half of them were not indexed in MEDLINE. The mean quality score of the Japanese studies was 6.7 and the proportion of high-quality studies (with a quality score higher than 8) was 32.6%. A significant difference was observed in several quality items between MEDLINE-indexed and non-indexed studies, although there was no difference in total quality score. Three variables (i.e., target diseases, publication year, and study type) were identified as factors related to the quality of the studies. Conclusions of Japanese studies relating to several target diseases were relatively consistent with international assessments.

Conclusions: Although a considerable number of diagnostic accuracy studies of PET have been conducted in Japan, a substantial proportion of high-quality studies were not indexed in international databases. High-quality Japanese studies, therefore, should be searched using Japanese databases and assessed by systematic reviews and HTA conducted internationally.

Keywords: Japan; PET; Positron emission tomography; QUADAS.