To our knowledge, the EPM trial is the first RCT to compare the effect of wearable activity tracker devices to enhance patients’ motivation for early mobilization in the ERAS setting. Cook et al. completed the first cohort study using a mobility tracker with 150 patients after cardiac surgery. The study showed that there was a significant relationship between the number of steps taken in the early recovery period, length of stay, and dismissal disposition [
21]. However, in this setting, only the relationship between step count and length of hospital stay was investigated, and there was no automatic feedback to the patients. Our present RCT will be the first study addressing surgical patients with the aim of enhancing patients’ intrinsic motivation for more postoperative mobilization through an automatic feedback mechanism. Martin et al. showed in an RCT that an automated mobile health intervention with a tracking device and a texting component can increase a patient’s physical activity, and it was successfully used as a behavior change driver in ambulatory cardiac patients [
24]. A problem was that only the text-messaging component of that study increased the physical activity. Chan et al. used pedometers to increased physical activity in a sedentary population of 106 participants. They suggested a count of 10,000 steps per day as an effective target for prevention of disease and promotion of a healthier lifestyle [
25]. Bed rest is associated with several complications, such as pneumonia, but solid data for visceral surgery are lacking [
26,
27]. However, self-tracking can be used in chronic disease cases as well. Authors of a recent meta-analysis of activity monitor-based counseling studies concluded that there are beneficial effects derived from self-tracking on physical activity, blood glucose, systolic blood pressure, and BMI in patients with diabetes [
28]. In patients with chronic obstructive pulmonary disease and chronic heart failure, the benefit was unclear owing to limited or nonexistent data [
28]. There is still a lack of evidence in other chronic diseases [
29]. The problem with early mobilization of surgical patients is the imposed immobility by devices such as drains and catheters [
19]. Even in the ERAS setting, an increase of early mobilization is difficult to implement [
30]. For example only 20–28% of patients were mobilized on the first POD after liver surgery, despite targets such as “four times daily” [
11,
31,
32]. Our first pilot study indicated a discrepancy between ERAS targets and actual practice in patients with comorbidities undergoing major visceral surgery. The data underlined the need for a prompt redefinition of ERAS mobilization targets [
19]. The use of activity trackers can be useful when defining these mobilization targets, monitoring postoperative patient parameters, and helping to implement the ERAS principles by increasing the patient’s intrinsic motivation.
The present trial includes many types of operations, including hepatopancreatic, GI, and colorectal surgery, which might have a different impact on the patients’ postoperative physiology and ability to ambulate. This broad range of operations was intended to increase the applicability and generalizability of the study. As a result, minor effects of the activity-tracking feedback that might be confined to only one type of surgery might be missed. However, our pilot study, although not powered for this endpoint, showed no significant difference in the achieved postoperative step counts between the different operations.
The present study further includes patients within a broad age range and associated fitness level. Differences in functional abilities naturally occurring with aging [
33] and that might be aggravated after surgery can further bias the study, but they might contribute to the applicability of the results. In addition, the potential for discrepancies between the self-reported preoperative mobility assessed by the IPAQ and actual quantitative mobility cannot be excluded. In addition, the IPAQ was not designed for patients in a hospital setting (i.e., inpatients). Nevertheless, the IPAQ is considered an appropriate tool to assess physical activity in daily life, and results derived from it will be analyzed as a secondary endpoint in the present trial [
34].