Journal Article Annotations
2021, 2nd Quarter
Annotations by Sahil Munjal, MD
April, 2021
The finding:
High depressive symptoms (CES- D≥10) were associated with a 39% increased risk of rapid kidney function decline among a population of patients with normal kidney function in China. Depressive symptoms were assessed with the Center for Epidemiology Studies Depression (CES-D) scale with a median follow-up of four years. Four specific depressive symptoms (bothered by things, had trouble concentrating, felt everything was an effort, and felt lonely) were significantly associated with rapid kidney function decline (defined as an annualized decline in eGFR of at least 5 mL/min/1.73m2).
Strength and weaknesses:
Data were taken from a nationally representative, longitudinal study with measurements of both serum creatinine and cystatin C (more accurate representation of GFR levels). All participants were assessed by one-to-one interviews with a structured questionnaire.
The risk of residual confounding could not be fully excluded. Kidney function was not assessed during interim follow-up visits. Urine protein or albumin data were not available, as was information about psychiatric diagnosis at baseline. Study population had high depressive symptoms which may be moderated by different psychosocial factors, so the findings may be of limited generalizability.
Relevance:
Chronic kidney disease (CKD) is a leading risk factor for cardiovascular disease, kidney failure, and mortality, and depressive symptoms are a risk factor for CKD. The relationship may be explained by several biological factors including inflammatory cytokines, impairment in immune function, health literacy, and unhealthy lifestyle choices. The study highlights the importance of depressive symptom screening and effective interventions to improve primary prevention of CKD.
Type of study (EBM guide):
Cohort study
The finding:
Cognitive impairment is almost universal among patients with chronic kidney disease. However, it is unclear when to time cognitive testing for patients receiving dialysis. The study showed no measurable differences in cognitive performance (RBANS, Repeatable Battery for the Assessment of Neuropsychological Status) among ESRD patients during dialysis cycle (first 2 h, last 2 h) and a day after.
Strength and weaknesses:
This was a prospective randomized study with a high completion rate. The extensive neurocognitive test battery used is more sensitive than screening tests and has been validated for showing an absence of learning effects when retesting. Limitations include a small sample size(n=26), slightly younger patient sample (65y), overrepresentation of male subjects (73%), and possible selection bias. The study was conducted in Germany which may limit generalizability.
Relevance:
Previous studies have shown a high prevalence of cognitive impairment in patients with ESRD (51-87%), emphasizing the need for increased assessment. There are a multitude of factors that cause cognitive impairment in this population including older age, worsening kidney function, uraemia, cerebrovascular disease, depression, and intradialytic hypotension. These findings contrast with previous studies that suggest patients demonstrate their best cognitive performance after dialysis. Given the importance of cognitive skills to understand and follow health-related information, larger studies are needed to ascertain how cognition varies with respect to timing of dialysis.
Type of study (EBM guide):
Cohort study