Patient Disposition and Baseline Characteristics
Two hundred eighty-two T2D patients were enrolled in the study according to baseline HbA1c level stratification, i.e., HbA1c < 7.5% (58 mmol/mol) (n = 131) or HbA1c ≥ 7.5% (n = 151). They were then randomly assigned to two groups of 141 participants for either telemonitoring (TMG) or standard (CG) management. Nineteen participants were lost to follow-up (13 in the TMG and six in the CG) (Fig. 1).
The analysis set comprised 263 individuals (128 in the TMG and 135 in the CG) who had at least one HbA1c measurement during the follow-up period. Multivariate analyses were based on 256 participants (126 in the TMG and 130 in the CG) with no missing data among the variables entered in the model (data and confounding factors defined a priori). Finally, 242 individuals presented with an HbA1c measurement at 12 months, i.e., at the end of the intervention period.
The baseline characteristics of the study population show no difference between the two groups (Table 1).
Table 1 Main baseline characteristics Frequency of Device Use in Telemonitored Patients
In the TMG, the mean number of connections to the device by patient was 104 ± 78 (median value: 86) over the 12-month follow-up period, which corresponds to a frequency of about twice a week. Users could access the different device functions at each connection. Mean data synthesis (TMGs) and Nutri-Educ software (TMGn) access figures were 44 ± 49 (median value: 29) and 48 ± 61 (median value: 31), respectively, demonstrating almost weekly use. On average, TMG patients sent 14 ± 13 messages (median value: 11) to the investigators, i.e., about one message per month. The mean messaging frequency from the investigators to the participants was 5 ± 5 (median value: 3).
Primary Outcome: Changes in HbA1c over the Intervention Period
During the 12-month intervention period, the mean HbA1c level dropped from 7.8 ± 0.8% (62 mmol/mol) to 7.4 ± 1.0% (57 mmol/mol) in the TMG and from 7.8 ± 0.8% (62 mmol/mol) to 7.6 ± 1.0% (60 mmol/mol) in the CG. Among individuals with measurements available at 12 months, no significant decrease in the mean HbA1c level was recorded in the TMG compared to the CG: − 0.19% (95% CI [− 0.43; 0.05], p = 0.12). Moreover, the remaining difference between HbA1c value achieved at 12 months and the target initially set with the investigator (available for 241 participants) was not significantly lower in the TMG compared to the CG (− 0.13%, [− 0.37; 0.10], p = 0.27).
After adjustment for confounding factors, the intergroup difference was − 0.16% (95% CI [− 0.32; 0.01], p = 0.06), in favour of TMG (Fig. 2). The change predicted by the adjusted model showed an improvement in HbA1c level from T0 to T12: 7.75% (95% CI [7.65; 7.85]) (61 mmol/mol) to 7.49% (95% CI [7.31; 7.66]) (58 mmol/mol) in the TMG and to 7.64% (95% CI [7.47; 7.82]) (60 mmol/mol) in the CG.
Taking into account stratification on baseline HbA1c, the intergroup difference in terms of change was − 0.13 (95% CI [ − 0.32; 0.05], p = 0.16) in the lower stratum (HbA1c < 7.5%, n = 120), and − 0.19 (95% CI [− 0.45; 0.07], p = 0.16) in the upper stratum (HbA1c ≥ 7.5%, n = 136). We found no interaction between baseline HbA1c stratum and telemonitoring intervention regarding changes in HbA1c levels (p = 0.55).
Individuals characterised as TMGs+ (connections to telemonitoring synthesis above the median) exhibited a greater decrease in HbA1c compared to the CG: − 0.23% (95% CI [− 0.43; − 0.03], p = 0.03), with a 12-month predicted change of − 0.31% (95% CI [− 0.53; − 0.10]) in TMGs+ versus − 0.08% [− 0.26; 0.09] in CG, moving from 7.75% (61 mmol/mol) to 7.42% (58 mmol/mol) for TMGs+ versus 7.64% (60 mmol/mol) for CG. Similarly, a fall in HbA1c levels was more important in TMGn+ (connections to Nutri-Educ above the median) than in CG participants: − 0.21% (95% CI [− 0.41; − 0.00]), p = 0.05), with a 12-month predicted decrease of − 0.29% (95% CI [− 0.51; − 0.07]) in TMGn+ versus − 0.09% [− 0.26; 0.09] in CG, moving from 7.75% (61 mmol/mol) to 7.44% (58 mmol/mol) for TMGn+ versus 7.64% (60 mmol/mol) for GC (Table 2).
Table 2 HbA1c changes according to randomisation group (N = 256) and frequency of device use Secondary Outcomes: Changes in BMI and Waist Circumference During the Intervention Period
Among individuals with data available over 12 months (n = 240), BMI decreased by 0.30 ± 1.9 kg/m2 + in the TMG and increased by 0.06 ± 1.3 kg/m2 in the CG resulting in a non-significant intergroup difference of − 0.36 kg/m2 (95% CI [− 0.76; 0.05], p = 0.08) in favour of the TMG. After adjustment for confounding factors (n = 236), the average predicted difference between the two groups was − 0.30 kg/m2, (95% CI [− 0.70; 0.09], p = 0.14) with an expected 12-month change of − 0.24 kg/m2 in the TMG versus 0.06 kg/m2 in the CG. The expected BMI changes between baseline and the end of intervention were − 0.40 kg/m2 ([− 0.80; 0.00]) in TMGs+ patients (versus 0.06 kg/m2 [ − 0.24; 0.35] in CG patients), and − 0.53 kg/m2 [− 0.93; − 0.14] in TMGn+ patients, reflecting an anticipated respective difference of − 0.46 kg/m2 ([− 0.94; 0.02], p = 0.06) and − 0.57 kg/m2 ([− 1.05; − 0.09], p = 0.02) relative to CG patients.
In patients with available waist circumference values, unadjusted (n = 206) and adjusted (n = 202) intergroup differences were − 1.67 cm ([− 3.27; − 0.06], p = 0.04) and − 1.29 cm ([− 2.87; 0.30], p = 0.11), respectively, both in favour of the TMG. Intergroup differences were more pronounced in frequent users: − 2.00 cm ([− 3.90; − 0.10], p = 0.04) between TMGs+ and CG patients and − 2.64 cm ([− 4.60; − 0.68], p = 0.008) between TMGn+ and CG patients.
Stratified Analyses According to Gender (Table 3)
Table 3 Changes in body weight and BMI by group and device use, stratified on gender Predicted differences in HbA1c (primary endpoint) were − 0.21% ([− 0.48; 0.05], p = 0.12) in women and − 0.15% ([− 0.35; 0.05], p = 0.15) in men, in favour of TMG patients.
Intergroup differences in BMI (TMG versus CG) were − 1.01 kg/m2 ([− 1.79; − 0.23], p = 0.01) in women and 0.16 kg/m2 ([ − 0.27; 0.60], p = 0.46) in men. According to the frequency of use, BMI differences of − 1.23 kg/m2 ([− 2.16; − 0.31], p = 0.009) were documented in TMGs+ women and − 1.40 kg/m2 ([− 2.31; − 0.48], p = 0.003) in TMGn+ women. In terms of body weight, women in the TMG lost 2.7 kg ([− 4.79; − 0.57], p = 0.01) more than those in the CG group and up to 3.7 kg ([− 6.30; − 1.11], p = 0.005) in TMGs+ and − 3.78 kg ([− 6.25; − 1.31], p = 0.003) in TMGn+ women. No significant changes in waist circumference were observed (data not shown).
Correlation Between Device Use and Changes in HbA1c and BMI (Fig. 3)
HbA1c significantly decreased over the 12-month intervention period as the number of connections to telemonitoring syntheses increased (− 0.16 [− 0.32; − 0.003], p = 0.04). No significant correlation was found between this frequency of use indicator and change in BMI (p = 0.28).
The number of connections to Nutri-Educ tended to be correlated with changes in HbA1c (− 0.15 [− 0.31; 0.02], p = 0.08) and was significantly correlated with changes in BMI (− 0.30 [− 0.58; − 0.02], p = 0.03).
Device User Satisfaction (Fig. 4)
At the end of the 12-month intervention period, 91.0% of telemonitored individuals completed the satisfaction questionnaire; 97.4% were completely satisfied or rather satisfied with device use and telemonitoring data synthesis. Very high levels of satisfaction (very satisfied or rather satisfied) were also recorded regarding the assistance provided by the device in terms of improving their knowledge on diabetes (87.6%) and nutrition (84.3%). Device-generated assistance was deemed positive by 88.2% of subjects for the daily management of diabetes, by 81% for ensuring a balanced diet and by 85.5% for the practice of physical activity.
Fifty-five percentage of the investigators completed the satisfaction questionnaire; 85% of them reported having completely integrated the web application functions and over 80% found it easy to very easy to use, in terms of both patient records and telemonitoring synthesis reports. Finally, 82.3% were keen to continue using the device.