In this study, we assessed the relationship between DMSE and the rate of limb amputation in DMPs. Our results showed that the DMSES had a significant relationship with DM amputation, and with increasing a unit of DMSES, limb amputation would reduce by 3%. This result was consistent with a systematic review conducted by Xu Xy et al. [19] indicating a relationship between SE and patient health literacy. This study stated that various factors such as education level, employment status, annual income, social support, clarity of doctor’s explanations, and understanding of empowerment have a relationship between SE, health literacy, and DM management. Although, most of the evidence confirmed that patients with higher SE have better adherence to SC behaviors and high quality of SE required for better self-management of DM [20], however, Wending and Beadle showed no remarkable relationships between these two variables due to affecting SE and SC by some other contextual and motivational variables [21], furthermore, Al-Khawaldeh found higher self-efficacy is accompanying with better self-management behaviors in diet, exercise, blood sugar testing, and taking medication [22], the controversies results demanded more qualitative and quantitative studies.

Based on the obtained results, the level of DMSES in the case and control groups was at an average level, and the results showed that the level of DMSES for DM management was considerably higher in control individuals. Based on the results of other studies, people with a higher SE score were less likely for lower limb amputation. In the study of MorvatiSharif Abad et al. [23], Davari et al. [24], and Bernal et al. [25], the results showed that DMPs had a moderate level of SE. In the present study, the average level of SE probably was associated with the age of the sample greater than 55 years which potentially continued low level of SE among all members of the society.

The average DMSE for DM management in patients with amputation and non-amputation were 60.6 and 67.7, respectively, which, there was a statistically significant difference. It was also observed that the DMSE affects the chance of amputation in DMPs. In the study of Willrich, A et al. [7], it was observed that the occurrence of chronic conditions such as lower limb ulcers or amputation had a considerable impact on the quality of life in DMPs. Thus, amputation is related to the decrease in physical and psychosocial status of DMPs and is also effective in the decline in cognitive function in these patients. Also, Pedras et al. [26] stated that several psychological factors can potentially affect the level of life quality in DMPs with amputation experiences. Since the DMSE had a direct relationship with the quality of life in patients [27], it can be concluded that the decline in quality of life in DMPs with amputation represented a lower DMSE level compared to patients with no amputation.

Based on the findings of this study, the average DMSE was found higher in urban patients. Following our results, other studies in Turkey [28] and India [29] found that DMSE is moderate and low in rural areas, affected by low education and knowledge of patients. Rahimi et al. [30] and Morowatisharifabad and Rouhani Tonekaboni [23] proved that academic education and health literacy lead to higher self-efficacy and more accurate implementation of care plans and sensitivity toward them.

Also, the findings showed a statistically significant difference between the average DMSE and family history of DM in the non-close relatives family (p < 0.05) with a higher of DMPs with a family history of DM in the non-close relatives family. In line with our findings, there was no significant relationship between the average DMSE and family history of type 1 DM in close relatives based on the studies of Davari et al. [24] and Rahimi et al. [30]. While the results of the current study were inconsistent with the results of Harati and colleagues because they achieved significant results in this regard [31]. Studies have shown that people with a family history of DM select a healthier way of life and they witnessed a significant relationship in that study [23, 30]. Our results showed that there is a significant relationship between the average DMSE and gender. The average DMSE was higher in women than men associated with the fact that women usually show more sensitivity towards the details and accurate and timely implementation of their care plans. In the study of Davari et al. [24] a significant relationship was also reported and the level of SE in women was higher than in men. However, in other studies, including Wendling and Beadle, the men’s SE score was higher than women and they showed more caring behavior than women [21].

The results of our study showed that there is no significant relationship between the average DMSE and marital status. Our results were in line with the results of Davari et al. [24], and Rahimi et al. [30]. Contrary to our results, the study of Mohseni Puya et al. [32] found a significant relationship between DMSE and marital status. In this study, it was stated that the level of SE in married DMPs is higher than those of single people, due to the emotional support [30]. Such differences between married and single DMPs returned to the support system such as family and spouse in married patients. It was also observed that married patients follow a healthy diet 1.27 times more than single individuals [33].

Strength and limitation.

Our study had some strengths, e.g. acceptable sample size, and subject recruitment from multicenters (diabetes clinics affiliated to KUMS), however there were some limitations including, Some of the patients who were referred to, stating that no useful action has been taken for them so far, refused to complete the questionnaire, therefor by observing the principle of freedom and informed consent to participate in the study and with explanations, we tried an attempt to include them in the research. The geographical dispersion of the statistical population made the time of data collection longer.