Validation of diabetes medication self-efficacy scale in Chinese with type 2 diabetes

Figures & data

Table 1 General characteristics of patients (n=257)

Characteristics	n (%) or mean ± SD
Sex
Men	143 (55.6%)
Women	114 (44.4%)
Age, years	57.0±11.2
Body mass index, kg/m^2	24.6±4.37
Education levels
Primary school	45 (17.5%)
Secondary school	91 (35.4%)
High school and above	121 (47.1%)
Marriage status
Married	235 (91.4%)
Separated/divorced	11 (4.28%)
Widowed	7 (2.72%)
Never married	4 (1.56%)
Employment status
Unemployed	44 (17.1%)
Employed	95 (37.0%)
Retired	118 (45.9%)
Monthly salary (RMB)
≤2,000	54 (21.0%)
2,001–4,000	114 (44.4%)
4,001–8,000	67 (26.1%)
>8,000	22 (8.56%)
Monthly medical expenditure (RMB)
≤500	132 (51.4%)
501–1,000	93 (36.2%)
1,001–2,000	27 (10.5%)
>2,000	5 (1.94%)
History of T2D	96 (37.4%)
Duration since T2D diagnosis	7.94±6.40
Fasting plasma glucose, mmol/L	8.53±2.73
HbA1c, %	8.70±2.30
Having T2D complications	163 (63.4%)
Having other diseases	108 (42.0%)
Duration of T2D medication usage	6.91±6.21
T2D medication typesa
Oral medications	234 (91.1%)
Insulin therapy	87 (33.8%)
Others	8 (3.11%)
Number of T2D medications usage	2.28±1.28
Daily frequency of T2D medications	2.85±1.55
Concurrent usage of other medications	116 (45.1%)
Encountered medication side effects	76 (29.6%)
Perception of T2D	6.26±2.97
Perception of T2D medications	6.04±3.06
Perception of T2D medication efficacy	6.74±2.44
Score of CDMSS	42.9±9.32
Score of VAS	78.5±20.0
Score of CDDS-15	2.99±0.93

Note:

a 68 patients used both oral medications and insulin therapy.

Abbreviations: CDDS-15, 15-item Chinese version of Diabetes Distress Scale; CDMSS, Chinese version of Diabetes Medication Self-efficacy Scale; HbA1c, hemoglobin A1c; RMB, Ren Min Bi (Chinese currency); T2D, type 2 diabetes; VAS, Visual Analog Scale.

Table 2 Patient response to the Diabetes Medication Self-efficacy Scale (n=257)

How sure are you that you can take your diabetes medicines if …	Not at all sure, n (%)	Somewhat sure, n (%)	Very sure, n (%)
1. You are busy at home	22 (8.6)	126 (49.0)	109 (42.4)
2. There is no one to remind you	18 (7.0)	117 (45.5)	122 (47.5)
3. They cause some side effects	53 (20.6)	134 (52.1)	70 (27.2)
4. You worry about taking them for the rest of your life	45 (17.5)	131 (51.0)	81 (31.5)
5. They cost a lot of money	51 (19.8)	126 (49.0)	80 (31.1)
6. You come home late from work or other activities	34 (13.2)	136 (52.9)	87 (33.9)
7. You do not have any symptoms of diabetes	19 (7.4)	91 (35.4)	147 (57.2)
8. You are with family members	5 (1.9)	106 (41.2)	146 (56.8)
9. You are in a public place	24 (9.3)	122 (47.5)	111 (43.2)
10. You feel you do not need them	44 (17.1)	95 (37.0)	118 (45.9)
11. You are traveling	23 (8.9)	121 (47.1)	113 (44.0)
12. You take them more than once a day	30 (11.7)	128 (49.8)	99 (38.5)
13. They sometimes make you tired	53 (20.6)	126 (49.0)	78 (30.4)
14. You have other medicines to take	35 (13.6)	140 (54.5)	82 (31.9)
15. You feel okay	11 (4.3)	92 (35.8)	154 (59.9)
16. You are shaky or jittery	48 (18.7)	120 (46.7)	89 (34.6)
17. You are confused	66 (25.7)	114 (44.4)	77 (30.0)
18. Your vision is blurry	57 (22.2)	114 (44.4)	86 (33.5)
19. You have a headache	48 (18.7)	122 (47.5)	87 (33.9)

Note: Copyright ©2016. Dove Medical Press. Reproduced from Sleath B, Carpenter DM, Blalock SJ, et al. Development of a new diabetes medication self-efficacy scale and its association with both reported problems in using diabetes medications and self-reported adherence. Patient Prefer Adherence. 2016;10:1003–1010.¹³

Table 3 Factor structure of Chinese version of Diabetes Medication Self-efficacy Scale (n=257)

	Factor 1	Factor 2	Factor 3
CDMSS 1a	0.79	−0.29	0.05
CDMSS 2a	0.77	−0.25	0.01
CDMSS 3a	0.72	−0.08	−0.34
CDMSS 4a	0.80	−0.06	−0.29
CDMSS 5a	0.80	−0.01	−0.30
CDMSS 6a	0.85	−0.05	0.01
CDMSS 7b	0.64	−0.15	0.55
CDMSS 8b	0.70	−0.04	0.44
CDMSS 9a	0.78	0.004	0.22
CDMSS 10b	0.52	−0.02	0.41
CDMSS 11a	0.72	0.07	0.33
CDMSS 12a	0.83	0.06	0.08
CDMSS 13a	0.84	0.12	−0.13
CDMSS 14a	0.82	0.16	−0.03
CDMSS 15b	0.55	0.02	0.56
CDMSS 16c	0.62	0.63	0.04
CDMSS 17c	0.72	0.48	−0.05
CDMSS 18c	0.66	0.58	−0.07
CDMSS 19c	0.70	0.54	−0.06

Notes:

a Items loaded on only one factor (Factor 1).

b Items loaded on two factors (Factor 1 and Factor 3).

c Items loaded on two factors (Factor 1 and Factor 2).

Abbreviation: CDMSS, Chinese version of Diabetes Medication Self-efficacy Scale.

Table 4 The Spearman’s rank correlation coefficients between the score of CDMSS-11, VAS, CDDS-15 and blood levels of FPG and HbA1c

CDMSS-11	Spearman’s r	P-value
VAS	0.56	<0.001
CDDS-15	−0.38	<0.001
FPG	−0.27	<0.001
HbA1c	−0.30	<0.001

Abbreviations: CDDS-15, 15-item of Chinese version of Diabetes Distress Scale; CDMSS-11, 11-item Chinese version of Diabetes Medication Self-efficacy Scale; FPG, fasting plasma glucose; HbA1c, hemoglobin A1c; VAS, Visual Analog Scale.

Table 5 Relations between factors (demographic, clinical, medication usage and perception) and diabetes medication self-efficacy measured by the 11-item Chinese version of Diabetes Medication Self-efficacy Scale

Characteristics	Univariate analysis		Multivariate analysis
	Kruskal-Wallis H (P-valuea)	Spearman’s r (P-valueb)	Beta-coefficient (P-valuec)
Sex	1.05 (0.31)
Age, years		−0.11 (0.07)	−0.10 (0.13)
Body mass index, kg/m^2		0.06 (0.35)	0.06 (0.27)
Education levels	5.44 (0.07)
Marriage status	1.01 (0.80)
Employment status	2.75 (0.25)
Monthly salary	7.33 (0.06)
Monthly medical expenditure	0.28 (0.96)
History of T2D	0.01 (0.91)
Duration since T2D diagnosis		−0.09 (0.13)	−0.24 (0.08)
Having T2D complications	7.69d (0.01)
Having other diseases	1.47 (0.23)
Duration of T2D medication usage		−0.04 (0.53)	0.21 (0.13)
T2D medication types
Under oral medications	2.26 (0.13)
Under insulin therapy	5.44e (0.02)
Under other medications	2.90 (0.09)
Number of T2D medications usage		−0.01 (0.92)	0.01 (0.94)
Daily frequency of T2D medications		−0.08 (0.20)	−0.08 (0.32)
Concurrent usage of other medications	12.81e(0.05)
Encountered medication side effects	18.04f (<0.001)
Perception of T2D		0.28f (<0.001)	−0.01 (0.92)
Perception of T2D medications		0.33f (<0.001)	0.25 (0.05)
Perception of T2D medication efficacy		0.31f (<0.001)	0.18e (0.012)

Notes:

a P-values were calculated based on the Kruskal-Wallis H test for categorical variables;

b P-values were calculated based on the Spearman’s rank correlation coefficient for continuous variables in the univariate analysis;

c P-values were calculated based on the linear regression for continuous variables in the multivariate analysis;

d P<0.01;

e P<0.05;

f P<0.001.

Abbreviation: T2D, type 2 diabetes.

SleathBCarpenterDMBlalockSJDevelopment of a new diabetes medication self-efficacy scale and its association with both reported problems in using diabetes medications and self-reported adherencePatient Prefer Adherence2016101003101027354769

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Data availability statement

The data that support the findings of this study are available on reasonable request from the corresponding author MZ. The data are not publicly available due to their containing information that could compromise the privacy of research participants.