A total of 126 IC patients wore the device correctly at baseline and were considered eligible for this study (figure 1). Analysis of the accelerometer data demonstrated that 17 subjects did not wore the device correctly for =5 days at follow up. In six cases the internal memory card malfunctioned and data were not stored, another eight participants refused a follow up measurement and another 38 subjects were lost to follow up (36.5%). As a consequence, data of 57 participants could be used for analysis (45.2%), of which 10 patients received a vascular intervention during the study period and 6 did not receive SET due to inadequate health care insurance. The present study reflects the results obtained from 41 patients (35.3% of the total study population). Baseline characteristics regarding both the included and excluded study population are depicted in table 1.
ACSM recommendations in IC patients
A total of 18 participants achieved the lower limit of the ACSM recommendations (67 METs?min a day) and 12 of them even met the ACSM upper limit (107 METs?min a day) as well at baseline line. The number of participants meeting the lower limit of the ACSM recommendations was significantly lower at baseline (n=18, 43%) compared to the numbers at 3 months of follow up (n=26, 63%, p=.003, figure 2). Of the initial 18 participants that achieved the lower limit of the ACSM recommendations at baseline, 16 achieved the lower limit at follow up (figure 2) again, while the remaining other two did not. From the 12 participants who achieved the higher limit of the ACSM recommendations at baseline (29%), eight achieved the higher limit again after 3 months (figure 2). In total 14 subjects met the ACSM higher limit (34%).
Daily level of physical activity in IC patients
Mean daily PA level (in METs?min) was normally distributed. No significant difference in mean daily PA level was found after 3 months of SET (baseline: 395 ± 220 METs?min vs. 3 months: 411 ± 228 METs?min, p=.43; figure 3). Moreover, daily PA levels performed in bouts of >10 minutes were also not significantly different after 3 months
(p=.13; figure 3). No significant correlation coefficients were found between the change in mean daily PA (METs?min) or mean daily PA in bouts and the increase in MWD (?mean daily PA vs. ?MWD: r=.21, p=.19; ?mean daily PA in bouts vs. ?MWD: r=.30, p=.06).
Time consumption and intensity of various activities
Table 2 depicts the time consumption and intensity of the various daily activities of IC patient. Data was non-normally distributed. No significant changes were found after 3 months of SET. Analysis of the intensity levels did also not show any significant differences between baseline and 3-months values (table 2). However, the mean maximal number of consecutive steps (top period of steps), which was normally distributed, was significantly higher after 3 months of SET (1914 ± 1473 vs. 2390 ± 1904, p<.05).
Walking distances and quality of life
PFWD, MWD and total WIQ score significantly improved following SET (table 3). Moreover, quality of life as reflected by SF-36 scores showed a significant increase in the physical functioning (PF) and the bodily pain (BP) role (table 3). No significant correlation was found between the increase in both QoL roles and an improvement in maximal walking distance (?PF vs. ?MWD: r=-.07, p=.75; ?BP vs. ?MWD: r=.08, p=.73).