Anxiety, Comorbid Depression, and Dialysis Symptom Burden

• depression
• anxiety

Patients with kidney failure receiving hemodialysis experience substantial illness and treatment burden. The psychologic experience of patients facing dialysis can be varied, and although depression is common, there has been a growing awareness that anxiety is also common and significant. Anxiety has been associated with all-cause mortality, increased hospitalization rates, and increased length of stay. However, anxiety remains understudied, and its relationship to dialysis and patient-reported outcomes is not well understood.

Anxiety is not itself a psychiatric diagnosis but rather a category of disorders, of which all have a hallmark type of anxious concern. (1) Generalized anxiety disorder is marked by excessive worry, (2) panic disorder is marked by anxious concern over bodily experiences (somatic anxiety), and (3) phobias are fears of particular things or situations. It is not yet known which specific components of anxiety may be associated with dialysis symptom burden or co-occurring depression.

In this single-center, cross-sectional survey study conducted in the summer of 2018 in New York City, consecutive English-speaking patients on hemodialysis (126) were approached until 100 completed an assessment of depression symptoms (the Patient Health Questionnaire-9) (1), worry (the Generalized Anxiety Disorder-7) (2), somatic anxiety (the Beck Anxiety Inventory [BAI]) (3,4), and dialysis symptom burden (the Dialysis Symptom Index) (5). Medical charts were extracted for demographic information and two measures of adherence: (1) any missed dialysis sessions in the past 30 days (not rescheduled or due to hospitalization) and (2) average interdialytic weight gain over the past three dialysis treatments. A stepwise linear regression was used to examine the association of depression, worry, and somatic anxiety with symptom burden, adjusting for covariates (step 1: demographics; step 2: demographics plus depression; step 3: step 2 plus worry and somatic anxiety).

The characteristics of the sample are found in Table 1. Overall, the sample reported low levels of anxiety and depression, but a significant minority demonstrated clinical elevation in symptoms of depression (23%), worry (12%), and somatic anxiety (22%). There was significant overlap between these conditions; 83% of those scoring high for worry also had elevated depression symptom scores, whereas 43% of those with high–somatic anxiety scores also had high worry scores. In unadjusted analyses, there were strong correlations between levels of somatic anxiety (r=0.70, P<0.001), depression (r=0.70, P<0.001), and worry (r=0.52, P<0.001) with symptom burden but not measures of adherence (P=0.05, all cases).

Participants with elevated somatic anxiety (BAI >15) had a significantly higher prevalence of depression and worry, more dialysis symptoms, and higher dialysis symptom severity scores (P<0.001, all cases).

In a predictive model of symptom burden, age, sex, and race were not significantly associated with symptom burden (step 1; P=0.05, all variables). Depression was significantly associated with symptom burden after accounting for demographics (step 2). Somatic anxiety was significantly associated with symptom burden (β-coefficient=1.26, P<0.001) in the final model (step 3), whereas worry was not. Depression accounted for 40% of the variance in symptom burden, and somatic anxiety accounted for an additional 27%.

Comorbid depression and anxiety are a challenge to conceptualize and treat in psychiatry. Because only 2% of the sample was identified as having worry but not depression, it would appear that either they co-occur frequently in this population or they have significant conceptual overlap. In contrast to this, 50% of the people with elevated somatic anxiety scores did not have elevated depression scores, and 22% of the sample had elevations in either depression or somatic anxiety exclusively. Patients with elevated depression or somatic anxiety scores reported more than double the number of symptoms and ranked their symptom severity as twice as severe. The additional symptom burden may be due to symptom burden causing increased psychologic distress, the psychiatric diagnoses contributing more symptoms, and/or increased sensitivity to and awareness of the dialysis symptoms experienced.

Anxious concern over bodily experiences may be particularly meaningful in patients receiving dialysis. Aside from psychologic distress, a key symptom of all anxiety disorders is anxious avoidance (the conscious avoidance of circumstances that are likely to produce distress). Although this survey did not have sufficient power to find an association between somatic anxiety and dialysis adherence, that may be due to our use of missed dialysis as a categorical variable. In future studies, the relationship between somatic anxiety and dialysis shortening should be explored, as the last portion of each treatment session is often marked by an increase in subjective symptoms. Other limitations of our design were the use of a convenience sample, the single center, the small sample size, and the use of screening instruments rather than gold standard measures.

It appears that the effects on symptom burden of depression and worry overlap significantly, but somatic anxiety, common in panic disorder, may be a unique contributor to excess symptom burden. Anxiety treatment strategies to target the extra symptom burden and distress as well as the resultant anxious avoidance are needed.

• Copyright © 2022 by the American Society of Nephrology