Between 2020 and 2023, PMI conducted time trend analysis studies (TTA Studies), including two in Japan that looked at third-party hospitalization data for chronic obstructive pulmonary disease and ischemic heart disease before and after the introduction of several competing brands of heated tobacco products, including IQOS.
As disclosed contemporaneously with the TTA Studies, ecological analyses such as these have many inherent limitations and are not designed to assess cause and effect. Given their inherent limitations, time trend analysis studies are used primarily to develop hypotheses for further research.
Upon PMI’s post-publication review of the TTA Studies, which identified certain inaccuracies in the study methodology, analyses and presentation of the data, PMI has determined that these TTA Studies and their conclusions are no longer useful and will no longer be relying on them for developing hypotheses or any other purpose.
Update (March 27, 2024): One of the TTA Studies was published in Frontiers In Public Health, a peer-reviewed journal, in June 2022. After learning of the inaccuracies in the studies, PMI promptly reached out to the journal and requested retraction of the study. PMI requested the retraction on July 20, 2023. To date, Frontiers In Public Health has not taken a decision on the request for retraction.