Effects of Motivational Interviewing Intervention on Self- Management and HbA1c in Type 2 Diabetes Patients
Phase: NA
Conditions: Type 2 Diabetes
Sponsor: Istanbul University - Cerrahpasa

Effects of Motivational Intervewing Intervention on Self- Management and HbA1c in Type 2 
Diabetes Patients 
Document Date: December 2, 2021 
 
Statistical Analysis Plan 
Descriptive analyses (arithmetic mean, standard deviation, minimum–maximum, ratio, 
percentage) were used to evaluate the similarities of the experimental and control groups, a Mann-
Whitney U Test was used to compare the experimental and control groups pretest and posttest 
Instrument scores, and a Wilcoxon signed-ranks test was used to compare the pretest and posttest 
scores of the experimental and control groups. The results were evaluated at a 95% confidence 
interval and a p <0.05 significance level. 
 
 
 
 
 
 
 
 
 

Study Protocol 
 
Results 
The research was conducted between February and December 2017. There were 60 people who 
met the inclusion criteria randomly assigned to the intervention and control groups.  
The individual characteristics of the diabetes patients are shown in Table 1. According to this, it 
was determined that the mean age of the patients in the intervention group was 56. 28 ± 8.18 years, 
56% of the patients were female and the mean BMI of the patients was 32.49 ± 6.41. The mean 

age of the patients in the control group was 55.54 ± 7.60 years, 69.2% of these patients were 
female, and the mean BMI of these patients was 33.54 ± 5.93. No significant differences were 
found when the personal characteristics of the intervention and control groups were compared. 
Table 1- Individual and Diabetes Characteristics of the Invertention and Control Groups 
Variable  
Intervention 
(n=25) 
Control 
(n=26) 
Statistic 
Z/ X2 
p 
Age (year) 
Min-Max (Median) 
40-69 (57) 
46-74 (55) 
-,632 
,527 
Mean±Sd 
56,28±8,18 
55,54±7,60 
Gender; n (%) 
Female 
14 (56) 
18 (69,2) 
,954 
,329 
Male  
11 (44) 
8 (30,8) 
BMI (kg/m2) 
Min-Max (Median) 
24,6-48,3 (30,8) 22,4-47 (32,8) ,962 
,318 
Mean±Sd 
32,49±6,41 
33,54±5,93 
Education;  
n (%) 
Literate 
1 (4) 
5 (19,2) 
4,737 ,192 
Primary/Secondary 
school 
21 (84) 
17 (65,4) 
High school and above 3 (12) 
4 (15,4) 
Occupation; n (%) 
Non-working 
10 (40) 
17 (65,4) 
6,400 ,094 
Salaried employee 
3 (12) 
5 (19,2) 
Retired 
10 (40) 
3 (11,5) 
Other 
2 (8) 
1 (3,8) 
Economic status; 
 n (%) 
Worse 
3 (12) 
1 (3,8) 
3,537 ,171 
Moderate 
20 (80) 
25 (96,2) 
Better 
2 (8) 
- 
People with whom 
he/she lives; n (%) 
Alone 
1 (4) 
2 (7,7) 
2,605 ,457 
Partner(wife/husband) 10 (40) 
6 (23,1) 
Partner and children 
14 (56) 
17 (65,4) 
Children 
- 
1 (3,8) 
Duration 
of 
diabetes 
(year)  
Min-Max (Median) 
1-20 (7) 
2-30 (10) 
-,454 
,649 
Mean±Sd 
9,20±5,70 
10,15±6,37 
Family history; n (%) 
Yes 
21 (84) 
23 (88,5) 
1,739 ,419 
No 
4 (16) 
2 (7,7) 
Don’t know 
- 
1 (3,8) 
Hospitalization in the past 
year 
for 
diabetes 
or 
complications; n (%) 
Yes 
2 (8) 
1 (3,8) 
,397 
,529 
No 
23 (92) 
25 (96,2) 
Regular check up; n (%) 
Yes 
7 (28) 
8 (30,8) 
,047 
,828 
No 
18 (72) 
18 (69,2) 

Diabetes theraphy; n (%) 
OAD 
2 (8) 
3 (11,5) 
3,248 ,197 
Insulin 
5 (20) 
1 (3,8) 
Insulin+ OAD 
18 (72) 
22 (84,6) 
Diabetes 
treatment 
compliance 
score 
according to VAS value 
Min-Max (Median) 
1-11 (4) 
0-6 (3) 
-2,958 ,003 
Mean±Ss 
5,16±2,40 
3,30±1,69 
A1C 
Min-Max (Median) 
8,4-15,3 (10) 
6,5-14,4 (10) 
-1,103 ,270 
±Ss 
10,66±1,91 
9,95±2,23 
 
Table 1 also shows the characteristics related to diabetes of the intervention and control groups. 
According to this, it was found that the mean duration of diabetes of the patients in the intervention 
group was 9.20 ± 5.70 years, 72% of these patients did not have regular health checks according 
to the self-reported Vizuel Analog Instrument (VAS) value, the mean score of their compliance 
with their diabetes treatment was 5.16 ± 2.40, and their mean HbA1c level was 10.66 ± 1.91. The 
mean duration of diabetes of the patients in the control group was 10.15 ± 6.37 years, 69.2% of 
these patients did not have regular health checks, the mean score of their compliance with their 
diabetes treatment was 3.30 ± 1.69, and their mean HbA1c level was 9.95 ± 2.23. When the 
characteristics of the illness of the patients in the intervention and control groups were compared, 
there were only significant differences between the mean scores of their compliance with their 
diabetes treatment, according to the self-reported VAS value; all other characteristics were the 
same. 
Table 2 shows a comparison of the pretest–posttest DSMS-35 scores of the intervention and 
control groups. A significant difference was found between the final test scores of the intervention 
and control groups when these data were compared (Z=-6.031, p<0.001). A significant difference 
was also found when a comparison was made between the preliminary test–final test DSMS-35 
scores within the intervention and control groups themselves (Z=-3.983, Z=-2.542 p<0.05). 

However, while the posttest DSMS-35 scores of the patients in the intervention group had 
increased, it was found that the final test DSMS-35 scores of the patients in the control group had 
decreased. 
Table 2- Comparison of the pre test – post test DSMS-35 Scores and HbA1c Values of the 
Intervention and Control Groups 
 
Intervention  (n= 25) 
Control (n= 26) 
 
Z** 
 
p 
Mean±Ss  
Min  
Max 
Mean±Ss  
Min  Max 
DSMS-35 
 Scores 
Pre test  
83,08±21,30 
47 
132 
80,38±16,08 
51 
106 
-,226 
,821 
Post test  
122,36±13,37 
87 
139 
73,92±12,93 
51 
100 
-6,031 
0,000 
Z*=-3,983 p =0,000 
Z*=-2,542 p =0,011 
 
 
HbA1c 
Pre test  
10,66±1,91 
8,4 
15,3 
9,95±2.23 
6,5 
14,4 
-1,103 
,270 
Post test  
7,20±1,32 
4,0 
10,3 
9,50±2,14 
06,4 
13,9 
-4,093 
0,000 
Z*=-4,373  p =0,000 
Z*=-1,258  p =,209 
 
 
p<0.05; *Z, Wilcoxon Signed Ranks Test;   **Z, Mann-Whitney U Test 
 
Table 2 also shows the comparison of the pretest–posttest HbA1c values of the intervention and 
control groups. A significant difference was found between the final test HbA1c values of the 
intervention and control groups (Z = -4.093, p<0.05). There was also a significant difference when 
the patient HbA1c values between the preliminary test and final test in the intervention group were 
compared (Z=-4,373, p<0,05), and it was seen that the final test HbA1c values were lower than 
the values prior to the intervention. No significant difference between the preliminary- and final-
test HbA1c values of the patients in the control group was found. (Z=-1,258, p>0,05).