3.1 Recruitment and follow-up
From March 2016 to April 2019, 887 individuals were screened and 92 were randomized (46 in each group). Eleven patients were excluded from effective analysis due to no any follow-up data after randomization. Eight patients discontinued IP: premature intervention discontinuation due to AE (N = 6), withdrawn consent (N = 1) and lost to follow-up (N = 1). These 8 patients were included in the FAS analysis but not in the PPS analysis. Eighty-one (88.0%) patients (43 in intervention group, 38 in control group) in total were included for the FAS analysis and 73 (79.3%) patients (37 in intervention group, 36 in control group) were included in the PPS (Figure 2).
Figure 2 Flowchart of participants through the trial
Abbreviations: FAS, full analysis set; PPS, per protocol set.
3.2 Patient characteristics
Baseline characteristics of study participants were similar in the two groups (details are shown in Table 1). More than half of the patients were male (N = 64, 69.7%). At baseline, the mean (±SD) age of the participants was 56.0±8.4 years and the average time from diagnosis of diabetes was 11.2±6.6 years. The mean body mass index (BMI) was 24.8±3.5 kg/m2 and the mean HbA1c was 9.0±1.4%. The median [IQR] UACR was 1245.0 [667.1, 2875.2] mg/g, while the median UAER was 1512.0 [782.5, 2818.0] mg/24-h. The mean eGFR was 70.4±23.4 mL/ min/1.73 m2.
Before run-in period, 35 participants (38.0%) were using metformin, 14 (15.2%) sulphonylurea and 69 (75.0%) insulin. A total of 75 (81.5%) and 70 (76.1%) of those randomized had diagnoses of hypertension and hyperlipidemia. The majority (N = 80, 87.0%) were using angiotensin-converting enzyme inhibitors (ACEI) or angiotensin II receptor blocker (ARB) and large numbers of participants (N = 80, 87.0%) were prescribed statin. A total of 25 (27.2%) reported a history of cardiovascular disease.
Table 1 Baseline characteristics of randomized participants
Variable†
|
Control
(n = 46)
|
Intervention
(n = 46)
|
Total
(n = 92)
|
Age (years)
|
56.2 (8.0)
|
55.9 (8.9)
|
56.0 (8.4)
|
Male, n (%)
|
29 (63.0)
|
35 (76.1)
|
64 (69.7)
|
Duration of diabetes (years)
|
11.4 (7.0)
|
10.9 (6.2)
|
11.2 (6.6)
|
HbA1c (%)
|
9.0 (1.3)
|
9.1 (1.4)
|
9.0 (1.4)
|
BMI (kg/m²)
|
23.5 (3.1)
|
26.1 (3.4)
|
24.8 (3.5)
|
Systolic BP (mmHg)
|
140.3 (14.6)
|
139.1 (16.7)
|
139.7 (15.6)
|
Diastolic BP (mmHg)
|
79.1 (7.5)
|
78.3 (8.3)
|
78.7 (7.9)
|
Triglycerides (mmol/L)
|
1.8 (1.1)
|
1.8 (0.9)
|
1.8 (1.0)
|
Total cholesterol (mmol/L)
|
5.1 (1.4)
|
5.1 (1.6)
|
5.1 (1.5)
|
HDL (mmol/L)
|
1.2 (0.3)
|
1.0 (0.4)
|
1.1 (0.3)
|
LDL (mmol/L)
|
3.2 (1.2)
|
3.0 (1.3)
|
3.1 (1.2)
|
eGFR‡ (mL/min/1.73 m²)
|
69.2 (24.6)
|
71.5 (22.5)
|
70.4 (23.4)
|
UACR (mg/g)
|
1380.9 [601.8, 2951.5]
|
1146.2 [709.4, 2488.2]
|
1245.0 [667.1, 2875.2]
|
UAER (mg/24-h)
|
1438.0 [531.0, 2852.0]
|
1721.0 [982.0, 2816.0]
|
1512.0 [782.5, 2818.0]
|
Current smoker, n (%)
|
18 (39.1)
|
23 (50.0)
|
41 (44.6)
|
Hypertension, n (%)
|
36 (78.4)
|
39 (84.8)
|
75 (81.5)
|
Hyperlipidemia, n (%)
|
35 (76.1)
|
35 (76.1)
|
70 (76.1)
|
Cardiovascular disease, n (%)
|
13 (28.3)
|
12 (26.1)
|
25 (27.2)
|
Sulfonylurea, n (%)
|
8 (17.4)
|
6 (13.0)
|
14 (15.2)
|
Metformin, n (%)
|
17 (37.0)
|
18 (39.1)
|
35 (38.0)
|
AG inhibitors, n (%)
|
11 (23.9)
|
13 (28.3)
|
24 (26.1)
|
Insulin, n (%)
|
33 (71.7)
|
36 (78.3)
|
69 (75.0)
|
Diuretic, n (%)
|
7 (15.2)
|
6 (13.0)
|
13 (14.1)
|
Calcium-channel blocker, n (%)
|
28 (60.9)
|
28 (60.9)
|
56 (60.9)
|
ACEI/ARB
|
40 (87.0)
|
40 (87.0)
|
80 (87.0)
|
Beta blocker, n (%)
|
4 (8.7)
|
9 (19.6)
|
13 (14.1)
|
Any anti-hypertensive, n (%)
|
41 (89.1)
|
42 (91.3)
|
83 (90.2)
|
Statin, n (%)
|
39 (84.8)
|
41 (89.1)
|
80 (87.0)
|
Any lipid-lowering drug, n (%)
|
40 (87.0)
|
42 (91.3)
|
82 (89.1)
|
Aspirin, n (%)
|
10 (21.7)
|
19 (41.3)
|
29 (31.5)
|
Any anti-platelets, n (%)
|
13 (28.3)
|
24 (52.2)
|
37 (40.2)
|
†. Numeric variables are presented as mean (SD) if normally distributed. Categorical variables are presented as frequency (%). UAER and UACR are presented as median [IQR].
‡. eGFR are calculated with the Chronic Kidney Disease Epidemiology Collaboration (CKD-EPI) equation.
Abbreviations: HbA1c, hemoglobin A1c; BMI, body mass index; BP, blood pressure; HDL, high density lipoprotein; LDL, low density lipoprotein; eGFR, estimated glomerular filtration rate; UACR, urinary albumin-to-creatinine ratio; UAER, urinary albumin excretion rate; AG, aminoglycosides; ACEI, angiotensin-converting enzyme inhibitors; ARB, angiotensin II receptor blocker.
3.3 Primary outcome
In the FAS analysis, the percentage change in UAER was significantly lower in the intervention group, leading a difference of -29.71% (95% CI: -55.27% to -4.15%, p = 0.0255) when comparing to the control group (percentage change in UAER: intervention group was 36.69±16.88%, control group was 66.40±17.42%). It was similar in the PPS analysis (percentage change in UAER: intervention group was 30.07±18.03%, control group was 58.89±18.03%, mean difference was -28.81% with a 95% CI of -55.90% to -1.72%, p = 0.0407) (Table 2 and Figure 3A).
Table 2 Changes after 24 weeks of follow-up
†Absolute mean difference between groups. All values expressed in mean ± standard error.
Abbreviations: FAS, full analysis set; PPS, per protocol set; CI, confidence interval; UAER, urinary albumin excretion rate; UACR,urinary albumin-to-creatinine ratio; HbA1c, hemoglobin A1c; FPG, fasting plasma glucose; BP, blood pressure; eGFR, estimated glomerular filtration rate.
Figure 3 Mean changes from baseline in the albuminuria according to the analysis of MMRM on FAS. (A) Percentage change in UAER (%); (B) Percentage change in ACR (%); (C) Change in UAER (mg/24-h); (D) Change in ACR (mg/g).
* for p<0.05. I bars indicate standard error.
Abbreviations: MMRM, mixed model repeated measures; FAS, full analysis set; UAER, urinary albumin excretion rate; ACR, albumin-to-creatinine ratio.
3.4 Secondary outcomes
The percentage change in UACR (intervention group was 80.93±21.13%, control group was 52.53±20.80%) was equivalent to the level of the percentage change in UAER, leading to an absolute mean difference of -28.40% (95% CI: -56.88 to -1.92, p = 0.0395). Although there was no significant difference between two groups for the change in UAER at 24 weeks, treatment effect on the change in UACR of exenatide group was greater than the control group (change in UACR: intervention group was 1405.93±276.87 mg/g, control group was 798.12±269.05 mg/g, mean difference was -607.80 mg/g with a 95% CI: of -1112.38 mg/g to -103.22 mg/g, p = 0.0209) (Table 2 and Figure 3B-D).
Both of the treatments reduced HbA1c, FPG and systolic BP at 24 weeks, but there were no significant differences between two groups. Among patients receiving exenatide plus insulin glargine, the mean body weight decreased 1.38±0.63 kg, while the mean body weight increased 1.30±0.66 kg among those receiving insulin lispro plus glargine, for a reduction of 2.68 kg (p = 0.0001) at week 24 (Table 2).
3.5 Tolerability and safety
The eGFR increased by 0.98±3.59 mL/min/1·73 m² in the control group and by 1.05±3.13 mL/min/1·73 m² in the intervention group at the first visit (week 4), then decreased by 9.19±2.47 mL/min/1·73 m² in the control group and by 4.64±2.34 mL/min/1·73 m² in the intervention group during the whole follow-up, with an absolute difference of 4.55 mL/min/1·73 m² (95% CI: –1.62 to 10.72; p = 0.1523).
Twenty-two adverse events in total had been recorded during the follow-up, while 6 patients (13.04%) in the control group and 16 (34.78%) in the intervention group (p = 0.015). Adverse events that led to discontinuation of the treatment occurred in 6 patients (13.04%) in the control group and in 5 (10.87%) in the intervention group (p = 0.726). Serious adverse events were reported in 4 patients (8.70%) in control group and in 1 (2.17%) patients in intervention group (p = 0.361). The majority of adverse events were gastrointestinal events and all of the 15 patients (32.61%) were in the intervention group (p <0.001). However, none of the gastrointestinal events had been considered as sever adverse events. Twenty patients (43.5%) in the control group and 10 patients (21.7%) in the intervention group declared to have been suffering hypoglycemia during the follow-up (p = 0.026). Furthermore, 2 patients in the control group occurred severe hypoglycemia and discontinued their participation (Table S2).