The ADAPT-DM study aimed to determine the prevalence of depression and anxiety, and their associated factors among Malaysian patients with diabetes. Regarding the prevalence of depression and anxiety, we found that 9% of the participants screened positive for anxiety and 20% met criteria for depression. The prevalence of depression reported in our study was similar to that reported in previous studies, where prevalence was estimated between 18% and 30% [23]. The prevalence of anxiety among participants in our study was relatively low compared to the prevalence reported by the INTERPRET-DD study, which estimated the prevalence of anxiety (all anxiety disorder included) to be 18% based on data collected from 3170 diabetic patients from 15 countries in different continents [24]. This may be explained by the difference in instruments used for assessing anxiety. While we used the GAD-7, which is designed to assess for generalized anxiety disorder (GAD), the INTERPRET-DD study used the Mini International Neuropsychiatric Interview. The prevalence of GAD specifically reported by the INTERPRET-DD study was 8.1%, which was similar to the prevalence of anxiety disorder reported in our study [24].
Our findings reveal that depression, neuroticism, and higher physical health-related quality of life increased the odds of developing anxiety by almost 25-fold, 9-fold, and 1.6-fold, respectively. Better psychological QOL was protective against anxiety and reduced the occurrence of anxiety by half (0.4-fold). The occurrence of depression greatly increased the odds of anxiety in our study, which is similar to what was reported in a study of 893 Chinese patients with diabetes [25]. The positive correlation between depression and anxiety is well documented in chronic illness, and the occurrence of depression can increase the risk of anxiety symptoms in patients with chronic illness [26, 27]. This relationship is expected as some theories suggested that anxiety and depression shared the same neurobiological mechanism in which they represent different phenotypic manifestations which run in a continuum [28]. The association between neuroticism and anxiety disorders, particularly generalized anxiety disorder and panic disorder, is well documented in the general population [29]. People with trait neuroticism tend to utilize maladaptive forms of emotional regulation rather than reappraisal which is believed to increase the severity of anxiety symptoms in these individuals [30]. Unexpectedly, our findings indicated that higher physical health-related QOL increases the odds of anxiety in diabetic patients. This is contradictory to previous findings which suggest anxiety is inversely correlated with all the components of QOL [31]. However, higher psychological QOL reduced the odds of anxiety disorders in diabetic patients, which is in line with the findings of other studies on patients with diabetes [31, 32].
Our study indicated that among demographic and social characteristics, older age and those with regular religious practice reduced odds of depression (by 0.96-fold and 0.08-fold respectively). Regarding clinical characteristics, those with anxiety had a 20-fold increased odds of developing depression. Greater physical health-related QOL reduced the occurrence of depression by 0.7-fold. Several studies have suggested that spirituality and religiosity are protective factors against depression [33–35]. In our sample, 79% of participants within the elderly age group (median age of 63 years) reported having a strong religious practice and those who have strong religious practice also had reduced odds of developing depression. Hence, strong religious practice could mediate the protective effect of older age against depression in our study. A bidirectional relationship between mood disorders and diabetes has been proposed, and the occurrence of anxiety is known to increase the risk of developing depression among patients [26, 27]. Our findings further support a bidirectional association between anxiety and depression among patients with diabetes, as reported by previous studies [9, 25]. We found that greater physical health-related QOL acts as a protective factor to reduce the odds of depression in diabetic patients. Similar results were found in a systematic review of 20 studies of diabetic patients across Europe and the United States [36]. Regarding personality traits, unlike previous studies in the general population, our findings did not suggest a predictive effect of neuroticism, extraversion, or conscientiousness on depression in patients with diabetes. This discrepancy may be explained by the presence of negative life events, a mediating factor in the relationship between personality traits and depression [37]. Many participants reported strong social support (80.3%). This factor coupled with a potential absence of current negative life events may reduce the predictive effect of neuroticism, extraversion, and conscientiousness on depression. Although our study did not assess negative life events, it may be the mediating factor which links personality traits to depression in diabetic patients.
The current study should be considered in light of its limitations. First, this study was conducted in a single tertiary healthcare referral centre. Hence, the findings may not be generalizable to the entire diabetic population in the country. Second, the cross-sectional design of the study does not allow determination of the causal relationship between the associated factors, depression and anxiety. Third, the depressive and anxiety symptoms were measured by self-reported tools rather than diagnostic interviews, which may affect the reliability of participant classification into the depressive and anxiety groups.
Despite these limitations, the study had many strengths. The data obtained included a wide range of factors that could potentially be associated with depression and anxiety in diabetic patients. The study sample demonstrated diagnostic heterogeneity (patients with type 1, type 2, and gestational diabetes were included), representative of the Malaysian diabetic population. Our study examined the association between personality traits, quality of life, depression, and anxiety in patients with diabetes, which has previously been poorly characterized. Our study highlights a need to screen not only for psychiatric complications of diabetes, such as depression and anxiety, but also personality traits and quality of life. Hence, management of diabetes mellitus requires a multidisciplinary team that can manage both
physical and mental health of patients.