This study sought to determine the prevalence of depression and the factors associated with it among adults with SCD attending the Mulago hospital SCD clinic. The results show a uniquely high proportion (68.2%) of adult patients with SCD suffering from depression.
When compared to previous studies the findings of a high prevalence of depression in SCD correlate with other studies which found up to 56.5% to have varying levels of depression (8). Another study found up to 40% of patients with SCD had depression (15). In a study by Schaeffer, et al that included 440 patients with SCD, up to 43.4% had depression and this was more closely associated with demographics than disease severity as measured by degree of anaemia (16). A study in Jamaica reported a slightly lower prevalence of depression in SCD (21.6%). This study population included patients with both SCD and thalassemia which may affect the disease severity (5). A study of patients living with SCD in USA found up to 20% of patients were depressed (17). The findings of this study in Mulago hospital, Uganda, generally show a much higher prevalence of depression in this group of patients than in other studies. This could be partly attributable to the effects of a lower socioeconomic environment which has been shown to increase the risk of depression (18). This study had more females, who have higher rates of depression,; however sex wasn’t a predictor of depression in this study.
We found 5 patients (2%) were suicidal, however this tool has limited ability to assess suicidal tendencies and more appropriate suicide risk tools would need to be applied to confirm this. These patients were referred to the mental health clinic.
The main factors found to be associated with depression in adult patients with SCD were the social support, level of education, painful crises over the past month and hospital admissions over the past six months.
Factors relating to disease severity such as haemoglobin level and presence of leg ulcers were not found to be significantly associated with depression among patients with SCD. This is in keeping with an earlier study that showed that depression in SCD was more closely linked with demographic and psychological aspects than with disease severity(16). This has been attributed to the adverse socioeconomic difficulties that patients of SCD suffer from due to the demands of the illness such as medical healthcare costs and disability from wide ranging complications (19).
Respondents whose perception of social support was found to be positive and adequate were less likely to suffer from depression. These respondents felt that they had a special person in their lives and it was a protective factor from suffering from depression. In this study, those having moderate to high social support rating were 33% less likely to have depression compared to those with low social support.
This is in agreement with other studies which demonstrated that patients with greater social support had less depressive symptomatology and social support was seen as one of the social determinants for overall health in the general population (20). Another study looking at perception and quality of social relationships further demonstrated that good perception of social support was protective against depressive disorders (21).
The other factor associated with depression was the level of education. Respondents who had secondary level education were 18% less likely to have depression compared to those who had never studied or had stopped at primary school level. The respondents who achieved tertiary level education were even less likely to have depression with a 24% lower likelihood of having depression as compared to those with no education or just primary level education.
In this study less than a quarter of the respondents had achieved tertiary level education. This could be a reflection of the limitations in social economic status or the challenges of living with a potentially debilitating disease. There have been several studies that have looked into and demonstrated that the level of education does indeed predispose to an increased risk of depression. A study in Canada looking at depression in type 2 diabetics found that having less than 12 years of formal education was associated with a significantly increased risk of depression. These type 2 diabetes patients were 50% more likely to have depression if they had less education (22). A large study in Norway looking at prevalence and factors associated with depression in the general population found similar results with education providing a cumulative protective effect the higher along one progressed with education (23).
Hospital admission over the past 6 months was also found to be significantly associated with depression. This is in agreement with other studies that demonstrated that depression in SCD was associated with increased hospital admissions. A study among African-Americans with SCD and depression found 44% of the subjects had been treated in the emergency room more than five times in the last year which was significantly higher than those without depression (8). This could be attributed to the fact that depression compounds symptoms like pain and complicates its treatment making patients more likely to experience crises that would necessitate hospital admission. It has been shown that chronically depressed sickle cell patients displayed increased frequency of vaso-occlusive crises and other complications (24).
A pain crisis experienced within the past month was also found to be significantly associated with depression in this study. Those who had experienced a pain crisis in the past month were 7% more likely to be depressed. This could be attributable to the impact of frequent vaso-occlusive crises on the quality of life of these individuals. It could also point towards the difficulty of controlling pain in depressed patients given that pain is one of the neuro-vegetative signs that may occur in depression, and therefore, focusing on only the physical aspects is inadequate for pain control.
Similar findings of the association between pain crises and depression in SCD were demonstrated by Wallen et al who found more frequent pain crises to be the most significant associated factor with depression and sleep disturbance disorders in adult patients with SCD (17). Hasan et al also supported similar findings in his study in the USA (7). More recently a study comparing SCD patients in Jamaica with depression to controls found that more painful crises (one or more per month) was among the factors significantly associated with depression in adults with SCD (5).
There was no association between self-esteem and depression in this study (P = 0.05). Similar results were found in a study in Benin (25).
Although there was a high proportion of depression, we were unable to grade the severity of depression because we used the SRQ-20 which is a screening tool. Other tools such as the Beck Depression Inventory could be applied in future studies to grade the severity of depression. It is also important to note that the SRQ-20 is a screening tool which could lead to over estimation of the findings.
Some of the complications of SCD such as pulmonary hypertension and renal disease were not assessed. It was therefore not possible to determine if there was any association between these other complications of SCD and depression.
There was also a recall bias caused by differences in the accuracy or completeness of the recollections retrieved by study participants regarding events or experiences from the past, this is a methodological issue due to use of interviews or questionnaires.
There are a significant number of adults with SCD attending the Mulago OPD with depression and there are currently no guidelines for screening these patients. This evidence could serve as a guide for clinicians to determine which patients are at risk of depression (e.g. those with frequent painful crises) and enable early identification and management of these patients in order to improve on treatment outcomes. This calls for integration of mental health services in the day to day running of the clinics offering services to those living with SCD. at the sickle cell OPD to offer holistic care.