Psychometric properties of the Malay version of the Diabetes Empowerment Scale among Hospital Serdang type 2 diabetes mellitus patients using exploratory factor analysis

Diabetes mellitus (DM) is an important public health problem in view of there is a tremendous increment in diabetes prevalence for the past two decades. In 20 years (1986 to 2006), the prevalence of DM has doubled from 6 to 12% [1]. Diabetes also has a high mortality and morbidity [2]. However the control rate among patients with DM in Malaysia is still inadequate [3].

Diabetes empowerment is a process of self-care of their diabetic condition. Patient with good empowerment has shown to have better health outcome [4, 5]. Thus, diabetes empowerment is considered a core component of diabetes care [6, 7]. Diabetes empowerment is integrated into healthcare system, which it involves educational intervention to increase one’s ability to think cautiously in the process of gain control over their diabetic condition subsequently improve their health-related outcomes [8]. Empowerment increases patients capacity to help themselves in their diabetes care [9], particularly to improve compliance rate of patients in practicing healthy lifestyle and medication uptake [10, 11]. Studies have shown patients who are involved in decisions regarding their care and management have better outcomes compared to those who are not [12, 13]. Furthermore, those patients who succeed in self-empowered will motivate other patients with diabetes in achieving a better glucose control [14, 15].

Diabetes Empowerment Scale (DES) has been developed as a tool to assess the self-empowerment [16]. Other than DES, there are another two instruments which are Diabetes Self-Management Questionnaire (DSMQ) [17] and Summary of diabetes self-care activities measure (SDSCA) [18, 19]. DSMQ is a 16-items questionnaire developed by Schmitt et al., 2013, to assess behaviors associated with metabolic control within common treatment regimens for type 1 and type 2 diabetes in adult patients. Validation of DSMQ showed it is reliable instrument with Cronbach’s alpha value of 0.84 (0.77 for subscale glucose management; 0.77 for dietary control; 0.76 for physical activity; and 0.57 for health care use). This questionnaire was performed among in-patient at a tertiary referral centres for diabetes, which the patients were having problems of diabetes treatment and poor glycaemic control with relatively long average diabetes duration and high prevalence of late complications. It is therefore the validation results couldn’t be generalized among the general diabetic population [17]. SDSCA is an 11-items questionnaire developed by Toobert et al., 1994 [18], later revised by Toobert et al., 2000 [19], assessing the following aspects of the diabetes regimen: general diet, specific diet, exercise, blood-glucose testing, foot care, and smoking. The average inter-item correlations within scales were high (mean = 0.47), with the exception of specific diet; test-retest correlations were moderate (mean = 0.40). Correlations with other measures of diet and exercise generally supported the validity of the SDSCA subscales (mean = 0.23) [18, 19]. Many translations of the SDSCA have been validated such as Spanish [4], German [20], Arabic [21], Turkish [22], Korean [23] including Malay [24]. The validated SDSCA in malay version by Bujang et al. (2016), reported that the cronbach’s alpha for the main domains based on the fieldwork were between 0.651 and 0.905 [24].

We chose DES for our study as the DES-28 questionnaire has the highest Cronbach’s alpha value compared to other scales (Cronbach’s alpha = 0.96) which is a good internal consistency [16]. The Cronbach’s alpha of each subscale was 0.93 for “managing the psycho-social aspects of diabetes”; 0.81 for “assessing dissatisfaction and readiness to change”; and 0.91 for “setting and achieving diabetes goals” [16]. On top of that, DES scale is designed specifically to measure the empowerment of the patient with diabetes. To the best of researcher knowledge, a validated empowerment questionnaire in local setting is unprecedented. This study aimed to translate the DES into the Malay language and to study the psychometric properties of the Malay version of the DES-M to facilitate its use for further research in the local setting.

The non-response rate was 25% and all of them did not give consent to join the study due to time constraint. In the end, a total of 151 diabetes patients were recruited into the analysis. Table 1 shows the demographic and medical background. Overall, the mean age was approximately 55 ± 13 years. More than half of the participants were male (66.2%) and two third were Malay ethnicity (61.6%). Majority of them married (92%) and received education at least secondary school and above (82.2%). More than half of the study participants have underlying hypertension (76.8%) and dyslipidaemia (60.3%). The mean duration of diabetes was 11 ± 9.43. On average, two third of the participants (66.2%) had not received any form of diabetes education program.

This study examined the internal consistency, concurrent and predictive validity of DES-M. The findings from this study indicate that the DES-M is a reliable and valid instrument for assessing diabetes empowerment in Malay-speaking population.

In this study, the DES-M exhibited a good internal consistency; Cronbach’s alpha coefficient for the total was 0.92, and the respective coefficients for the four sub-scales were 0.84, 0.75, 0.79 and 0.65. This is consistent with the findings with other studies such as the internal consistency of Sweden version of DES (Swe-DES-23) was 0.91 [32]; Iranian version of DES (IR-DES-28) was 0.89 [33] and Chinese version of DES (C-DES-20) was 0.86 [34]. To date, this is the first study of its kind related to Diabetes Empowerment scale in Malaysia and it shows that the DES-M is as good as Cronbach’s alpha coefficient as the English version and also others translated version of DES.

Criterion validity is used to determine how well of one measure in predicting the outcome for another measure. It can be classified into concurrent validity and predictive validity. Concurrent validity is defined as whether it measures what it is supposed to measure based on a well-established test. Concurrent validity was demonstrated by DES-M score positive correlated significantly to SDSCA (r = 0.313, p = 0.012), this result is coherent to Majouri et al., 2012, which IR-DES-28 was positively correlated to Diabetes attitude scale-33 (DAS-33)(r = 0.42, p < 0.01) [33].

Predictive validity is defined as the ability of an instrument in predicting the future health status of the participants and this appeared to be a better indicator for health-related outcome. Predictive validity was tested by using multiple regression linear regression, the result shows DES-M score could predict DQOL (B = 0.298, p < 0.001). Discriminant or divergent validity is defined as those items within any one subscale that highly distinctive with external items of another subscale [35]. Discriminant validity showed adequate correlations ranged from 0.257–0.744.

This study developed the Diabetes empowerment scale for diabetes patient among Malaysian population. This study also provide evidence that the DES-M is a valid and reliable, self-administered tool to measure self-empowerment among patient with diabetes.