Type of study: Cohort

The finding: Psychosocial distress, which includes depression, anxiety, and social distress, was frequent in patients undergoing maintenance dialysis and was associated with a shorter time to hospitalization. Almost half of the sample (n=80) had depression, anxiety, or social distress with the prevalence of moderate/severe depression and anxiety being 7 and 8 times respectively of the general population, highlighting the severe impact of end stage renal disease (ESRD) and its treatment on psychosocial well-being.

Strength and weaknesses: Strengths: Prospective design, which assessed whether psychosocial distress predicted an important acute health care utilization outcome in hemodialysis (HD) patients. It also claims to be the first study to examine the broader concept of psychosocial distress in the HD population.

Weaknesses: Study had a relatively small sample size (n= 80). The single-center nature of this study may also restrict the generalizability of these findings. They did not adjust for several important comorbid conditions individually, given the small sample size. Also, no data was collected about ethnicity, socioeconomic status, and educational level.

Relevance: About 1.4 million people are treated with HD for ESRD and the prevalence is expected to double by 2026 due to population aging and increased incidence of hypertension and type 2 diabetes mellitus. Psychosocial distress has been linked to negative health outcomes, such as mortality and hospitalization, in other chronic medical illness which has not yet been thoroughly studied in the HD population. This study highlights the high prevalence of psychological distress in this population. This points the clinician to incorporate psychological distress screening in routine clinical practice with HD patients which should be linked to a standardized response pathway to improve patient health outcomes. To assess the psychosocial distress during the HD treatment, they used the Generalized Anxiety Disorder screen (GAD-7), Patient Health Questionnaire-9 (PHQ-9) and the Social Difficulties Inventory (SDI-16), some of which are used commonly in clinical settings and clinicians are familiar with. More research is needed to further develop evidence-based treatments for psychosocial distress in patients with ESRD which may include cognitive-behavioral therapy, mindfulness, problem solving therapy and other psychotherapeutic resources.

Type of study: Retrospective, cross-sectional cohort study

The finding: The study evaluated national-level depression treatment patterns and predictors in US ambulatory care settings among adults with CKD and co-occurring depression. It found that adults with CKD and comorbid depression received some form of depression treatment at approximately half of the ambulatory care visits, mostly in the primary care setting. Antidepressants were the main form of depression treatment, SSRIs being the most common with very low use of psychotherapy. Odds of receiving antidepressants was positively associated with the total number of medications recorded during the sample visit. It also revealed regional disparities in depression treatment in this population, with ambulatory visits in the South were less likely to receive treatment than those in other regions of the US.

Strength and weaknesses: Strengths: Sample representative of the national population. Claims to be the first study to evaluate national-level depression treatment patterns and predictors in US ambulatory care settings among adults with CKD and co-occurring depression.

Weaknesses: Small sample size (unweighted N = 262). Results are based on one patient provider visit/encounter, and depression treatment may have been provided at other visits. Underreporting or misclassification of depression and CKD may have also occurred. It did not adjust for potential off-label antidepressant use such as for sleep, appetite stimulation, or pain. Information was also unavailable pertaining to duration and severity of CKD and depression, antidepressant dose, activities of daily living, and functional status. Lastly, given the retrospective, cross-sectional study design, causal inferences cannot be established.

Relevance: Depression affects up to 20% of adults in the US with CKD, even before initiation of dialysis, which we know is associated with poor outcomes. The study used data from the 2014–2015 National Ambulatory Medical Care Survey (NAMCS) which captures nationally representative information related to ambulatory medical services and provisions in non-federally employed physician offices. It was interesting to note that approximately at half of the ambulatory care visits, adults with CKD and comorbid depression received some form of depression treatment, predominantly SSRIs. This should be looked in conjunction with the recent CAST trial by Hedayati et al (2017) conducted among adults with non-dialysis-dependent CKD and depression which reported no difference between sertraline and placebo in improving depressive symptoms. It was also interesting to note in the study that bupropion and mirtazapine were the second most commonly prescribed antidepressants, even though metabolites from both are shown to accumulate in adults with ESRD, suggesting dose reduction. This may be due to their side-effect profiles, which can be used to treat symptoms common in both CKD and depression, such as fatigue/lack of energy and insomnia/poor appetite, respectively. There was very low use of psychotherapy and more studies are needed to study its effectiveness, considering the first-line antidepressants may be ineffective in this population. Further research is warranted to determine how to appropriately manage treatment of depression in adults with CKD.

Type of study: Case-control study

The finding: Serum levels of IL-6, but not BDNF, were elevated in hemodialysis patients with depression compared with hemodialysis patients without depression.

Strength and weaknesses: This multi-center study assessed levels of two inflammatory markers in a convenience sample of 274 patients on hemodialysis who also had symptoms of depression. Patients with active inflammatory conditions and those taking psychotropic medications were excluded from the study. Serum collections were done uniformly prior to the dialysis treatment. The main limitation of the study rises from the fact that the analysis did not control for several factors that can influence IL-6 or BDNF levels, such as smoking, medical comorbidities or certain medications.

Relevance: This study adds to the body of knowledge regarding the immune response in depression. The fact that IL-6 was elevated only in the depression group, despite both depression and non-depressed group having a significant chronic medical illness (chronic kidney disease), suggests that IL-6 may be proven in the future as a marker for depression. Such markers may become helpful diagnostic tools to distinguish depression from ill-related behavior.