Participant-Reported Reductions in Falls and Fall-Related Injuries Associated With Variable-Friction Footwear: Retrospective Pre-Post Survey Study.

Only 706 of 14,570 invited customers completed the survey, and one response was excluded, leaving 705 analysed, so respondents may not represent all users. Participants had to have kept using the shoes for at least 3 months, which may exclude people who stopped because of discomfort, lack of benefit, or safety concerns. The study had no concurrent control group and used retrospective self-report, so changes may reflect regression to the mean, expectation, recall, or other health changes. Falls, injuries, diagnoses, medical care, and costs were not verified against records or insurance claims. The reporting periods were unequal: the before period was 12 months, while the during period varied by participant. Important demographic and clinical variables such as sex, comorbidities, disease severity, and functional status were not collected. Participants who completed the survey entered a drawing for 1 of 5 free pairs of the same shoes. The shoe manufacturer helped identify customers and supplied the contact list, and one author is its founder and chief technology officer.

Funding came from the charitable arm of Rise Together Ventures, which Cadense secured. Cadense helped identify customers and supplied the contact list. One author is the founder and chief technology officer of Cadense and contributed to the study design, and another author is a Cadense employee.

Do not conclude that variable-friction shoes caused the reported fall reduction. The study had no concurrent control group, only 706 of 14,570 invited customers responded, and participants had already chosen to keep using the shoes for at least 3 months, so the finding is an association in a self-selected group.