Relationship among social support, treatment adherence and metabolic control of diabetes mellitus patients

This cross-sectional and quantitative study aimed to analyze the relationship among social support, adherence to non-pharmacological (diet and physical exercise) and pharmacological treatments (insulin and/or oral anti-diabetic medication) and clinical and metabolic control of 162 type 2 diabetes mellitus patients. Data were collected through instruments validated for Brazil. Social support was directly correlated with treatment adherence. Adherence to non-pharmacological treatment was inversely correlated with body mass index, and medication adherence was inversely correlated with diastolic blood pressure. There were no associations between social support and clinical and metabolic control variables. Findings indicate that social support can be useful to achieve treatment adherence. Studies with other designs should be developed to broaden the analysis of relations between social support and other variables. orales) y control clínico-metabólico de 162 personas con diabetes mellitus tipo 2. Se trata de un estudio seccional, de abordaje cuantitativo. Los datos fueron recolectados por medio de instrumentos validados. El apoyo social tuvo correlación directa con la adhesión al tratamiento. Se observó correlación inversa entre adhesión al tratamiento no medicamentoso y índice de masa corporal, así como entre adhesión medicamentosa y presión arterial diastólica. No hubo asociaciones entre apoyo social y variables de control clínico-metabólico. Se concluye que el apoyo social podrá ser útil para obtener la adhesión a los tratamientos. Estudios con otros delineamientos deben ser desarrollados, a fin de ampliar el análisis de las relaciones entre apoyo social y otras variables.


Introduction
Diabetes Mellitus (DM) stands out among nontransmissible chronic diseases because it is considered a public health problem due to its epidemic proportions. It constitutes a challenge to the health system and society because of the high financial and social costs to control and treat its complications (1) .
DM treatment aims to maintain metabolic control and basically comprises non-medication and medication therapy, the former of which is related to behavioral changes associated with a healthy diet and physical exercise (2) . Clinical-metabolic control includes glucose control, through glycated hemoglobin and fasting plasma glucose measures, as well as blood pressure and plasma lipid (triglyceride, total cholesterol and fractions) control, as the latter two conditions generally coexist in DM patients, constituting risk factors for cardiovascular disease (3) .
In this context, medication and non-medication treatment adherence represents a fundamental concept in care delivery to DM patients, and the understanding This study highlights Social Support (SS) among the factors that might influence treatment adherence. SS is considered a complex and dynamic process that involves individuals and their social networks, working to satisfy their needs, provide and complement the resources they have and, thus, cope with new situations (4) . The main sources can be family members and health professionals.
Studies suggest that SS is associated with adherence to medication and diet treatment. Others studies involving adults with DM revealed that people with a low SS perception presented significantly poorer glycemic control when exposed to highly stressful situations (5)(6) .
Although treatment adherence and SS have been largely studied, little attention has been paid to the relation between treatment adherence and perceived social support, or to the need for this support among people with DM (7) . Assessing SS is important to help nurses to plan appropriate interventions that can enhance people's adaptation to their disease (8) and, consequently, improve treatment adherence.
This study was developed in view of the need to know the perception of DM patients concerning SS and its relation to metabolic control and medication and nonmedication treatment adherence.

Aim
To analyze the relation between SS, non-medication treatment (diet and physical exercise) adherence, medication treatment adherence and clinical-metabolic control of type 2 Diabetes Mellitus patients under outpatient follow-up.

Methods
This sectional and quantitative study was carried out at a tertiary outpatient clinic in Ribeirao Preto, SP, Brazil between May and November 2008. The study population was selected through a weekly search of the medical profiles of people scheduled for appointments at the unit and who met the following inclusion criteria: minimum age of 40 years, medication treatment including insulin, oral anti-diabetic medication and/or associated medicines, absence of chronic complications in advanced stages, and ability to dialog. People older than 40 years were chosen because DM2 is most frequently diagnosed after this age.
Three instruments were used for data collection: Inventário da Rede de Suporte Social (IRSS), the translated version of The Social Support Network Inventory (9) , adapted and validated (α=0.95) for the Brazilian culture (8) , which serves to assess social network variables (source and type of contact) and perceived social support; Questionário das Atividades de Autocuidado com a Diabetes (QAAD), the translated version of the Diabetes Self-care Activities Questionnaire (11) , adapted and validated (α=0.75) for the Brazilian culture (10) , which assesses adherence to diet and physical exercise recommendations; and the Medida de Adesão aos Tratamentos (MAT), the translated version of the Morisky Test (13) , adapted to and validated (α=0.74) for the Portuguese language (12) and readapted to Brazilian Portuguese by Faria (14) , which serves to assess medication treatment adherence.
The use of the instruments was previously authorized by the authors of the original versions as well as by the authors of the translated and adapted versions.
Socio-demographic and clinical data, and information related to treatment and metabolic control (laboratory data) and life style were collected through a structured instrument that was tested in previous studies (15) .
The instruments were all read aloud, allowing the necessary time for each participant to fill them out. Data

Results
During the study period, 1,004 people were attended at the outpatient unit and, after analysis of their medical records, 309 (30.8%) met the inclusion criteria. Only 206 individuals could be contacted though.
Of these, nine were excluded due to physical/cognitive limitations; 22 refused due to the following: concern with the medical appointment or transportation, did not see any benefit in participating in the study; 13 did not attend the meeting on the scheduled day and time.
Therefore, the study sample comprised 162 people, which is equivalent to 16 (18) .
High levels of perceived SS were observed, with relatives as the main source, followed by health professionals. No statistically significant differences were found in mean SS with regard to gender, marital status and occupation. Weak but statistically significant correlations were observed though, between SS and age (r=0.20; p=0.01), as well as between SS and education, the latter of which was an inverse correlation (r=-0.23; p=0.03). These data suggest that, the higher the age, the higher the perceived SS. On the opposite, the higher the education level, the lower the perceived SS (17) . No statistically significant associations are observed between clinical-metabolic control and SS. With p set at <0.05, an inverse and statistically significant but weak correlation was observed between non-medication treatment adherence and BMI, as well as between medication adherence and diastolic blood pressure (Table 1).

Discussion
The relation between SS and socio-demographic characteristics in the study sample was explored in an earlier study (17) . In that study, a direct correlation was highlighted between SS and age, as well as an inverse correlation with education.
SS was directly correlated with medication and nonmedication treatment adherence, in line with literature findings (7,(19)(20) . The influence of family members and significant others may reinforce the health orientations DM patients receive, which could lead to higher adherence to diet and physical exercise recommendations as well as to medication treatment. On the other hand, this influence might conflict with health recommendations and hinder adherence (21) .
In the study group, a direct correlation was observed between the two adherence types under analysis. As opposed to literature, this finding suggests a close relation among different adherence aspects (22) .

This might be relevant for interventions to improve
adherence, that is, if one behavior tends to predict another, the same intervention might be an efficient means to increase adherence in more than one aspect of the treatment.
The correlation between SS and clinical-metabolic control was not statistically significant. Similar results were observed in two other studies. The first aimed to analyze the relation between SS, medication and non-medication treatment adherence and metabolic control in North American adult DM patients (23) , while the second focused on the effects of SS on the health, well-being and metabolic control of adult African DM patients (24) . The later study, however, showed that SS is an important determinant of DM patients' health and well-beings. It also benefits at least one aspect of disease management, which is blood pressure control.
This study's findings reveal a weak inverse correlation between adherence to non-medication treatment (diet and physical exercise) and the Body Mass Index (BMI). This data reinforces the importance of diet and physical exercise recommendations in BMI control. A study that investigated the relation between medication and non-medication treatment adherence and DM control in Jamaican adults found similar results (25) .
Regarding medication adherence, a weak inverse correlation was observed between this variable and 57 www.eerp.usp.br/rlae Gomes-Villas Boas LC, Foss MC, Freitas MCF, Pace AE.
mean diastolic blood pressure levels. In a study aimed at determining medication adherence among North American adult DM patients and its relation with the number of drugs prescribed and metabolic control, lower diastolic blood pressure levels were also identified among participants with higher medication adherence, although another instrument was used to assess adherence (26) .
For glucose control, assessed through glycated hemoglobin levels, no statistically significant correlations with SS were observed, similar to another study cited (23) .
No correlations were observed either between glycemic control and adherence variables, as opposed to authors who studied the relation between adherence and metabolic control among Finish adult DM patients (7) . It is highlighted that the latter study used another instrument for SS analysis.
In summary, the analysis of the relations between SS, medication and non-medication treatment adherence and clinical/metabolic control revealed that this study's findings are similar to those of studies carried out with DM patients, focusing on the relation between SS and adherence variables (7,(19)(20) , but diverge from the results of these same studies in terms of the relationship between SS and glycemic control, as well as between adherence variables and glycemic control.
On the other hand, the lack of association between adherence variables and glycemic control was also observed in another study (26) , without ignoring its clinical importance for care delivery to DM patients though. influence (22) .

Metabolic control is a complex set of interactions, in
which adherence is only one of the many related factors, and that is why its use as an adherence measure is of limited value (22) . It is also highlighted that most studies aim to analyze the relations between psychosocial variables and adherence, or between psychosocial variables and metabolic control. Few studies, however, have simultaneously investigated the relations between these three sets of variables, which justifies further studies of this kind.

Conclusion
Some limitations need to be taken into account.
The first refers to the type of study. As it assesses SS samples, in order to broaden the analyses of the relations between SS and other variables, and also to study the influences of nursing interventions in the recognition, change or reinforcement of social support to improve patients' health-disease conditions.