Impact of Itching on Health-Related Quality of Life in Patients on Dialysis

Patients with end-stage renal disease (ESRD) commonly experience multiple comorbidities, including fatigue, muscle cramps, itching, sleep problems, and depressive symptoms. The heavy symptom burden is associated with impaired health-related quality of life (HRQoL) in that patient population.

Chronic kidney disease-associated pruritus (itching) is a common and distressing symptom, and is experienced by both patients on hemodialysis and those on peritoneal dialysis; the prevalence is ~50% among patients with ESRD. Previous studies have demonstrated that itching is one of the 10 most burdensome symptoms associated with dialysis, and it is considered a research priority by patients, caregivers, and health care professionals.

The pathogenesis of itching in dialysis patients is not fully understood, but studies suggest that abnormal calcium, phosphate, and parathyroid hormone levels may influence the occurrence or burden of itching. In addition, opioid imbalance, peripheral neuropathy, dialysis efficiency, and dry skin may also be contributing factors. Itching is associated with adverse clinical outcomes such as hospitalization and mortality, as well as with poor patient-reported outcomes that include decreased HRQoL, depressive symptoms, and sleep problems.

According to Esmee M. Van Der Willik, PhD, and colleagues, there are few data available on the impact of itching on the course of HRQoL over time and the extent to which the combination of pruritus-associated symptoms affect patients’ physical and mental HRQoL. The researchers conducted a study to examine the impact of itching in dialysis patients by examining the persistence of itching, the effect of itching on the course of HRQoL, and the combined effect of itching with sleep problems and with psychological symptoms on HRQoL. Results were reported in Nephrology Dialysis Transplantation [doi.org/10.1093/ndt/gfC022].

The study utilized data from RENINE, the nationwide Dutch renal registry of patients receiving renal replacement therapy. The registry collects data on demographics and clinical characteristics as well as patient-reported outcome measures (PROMs). PROMs include the 12-item Short Form Health Survey to assess HRQoL and the Dialysis Symptom Index to assess symptom burden. Data from 2018 to 2020 were included in the current analysis.

The primary analyses were conducted both cross-sectionally and longitudinally to ensure that all patients and all PROMs measurements would be included. Cross-sectional analysis was conducted at baseline and included all patients in the study population. The longitudinal analysis included all PROMs measurements (n=5042), with 40.9% of the total cohort having multiple measurements.

A total of 2978 patients completed PROMs at least once during the study period. Of those, approximately half experienced itching at baseline (the time of the patient’s first PROM measurement). Itching was more common among patients receiving peritoneal dialysis (59.4%) compared with those receiving hemodialysis (48.7%).

Compared with patients without itching, those with itching were more often male, had a higher socioeconomic status, and more often had diabetes as the primary kidney disease. There were no differences between the two groups in calcium, phosphate, and parathyroid hormone levels. Patients without itching reported lower total symptom burden compared with those with itching (average 8 symptoms with a median total burden score of 19 vs average 14 symptoms with a median total burden score of 35, respectively). Patients with itching more often had dry skin compared with those without itching (73% vs 43%, respectively). Sleep problems were experienced by 70% of patients with itching compared with 52% of patients without itching. Psychological symptoms occurred in 36% of patients with itching compared with 19% of patients without itching.

Multiple PROMs were available for 1218 patients, with an average 6.7 months between baseline and the second measurement. During the total study period, the prevalence of itching was ~50% with a moderate burden. There were no clear differences in prevalence or burden of itching between the yearly quartiles (ie, no seasonal effects). Of the patients who experienced itching at baseline, itching persisted over time in ~70%. Among the patients who did not experience itching at baseline, 30% to 40% developed itching during follow-up. The majority of patients also experienced persistent sleep problems and psychological symptoms over time.

Mean physical and mental HRQoL scores in the total dialysis population were 35.8 and 48.1, respectively. Patients with itching experienced a lower physical (–3.35; 95% CI –4.12 to –2.59; P<.001) and mental HRQoL (–3.79; 95% CI, –4.56 to –3.03; P<.001) compared with those without itching. There were additional negative effects on HRQoL with sleep problems and psychological symptoms. There was no interaction between itching and sleep problems or psychological symptoms in the association with HRQoL.

HRQoL remained stable during the 2-year study period and there were no differences in trajectories between patients with itching and those without itching. A post hoc subgroup analysis showed an increase in physical and mental HRQoL when itching disappeared (+0.56 [P=.49] and +1.78 [P=.02], respectively), and a decrease when itching newly occurred (–0.44 [P=.61] and –0.68 [P=.38], respectively) between the first and second PROMs measurements.

The researchers cited some limitations to the study findings, including only dialysis patients, the lack of available data on treatments that may have induced or reduced itching, and the lack of information regarding factors that may influence itching.

In conclusion, the authors said, “The high prevalence and persistence of itching, its impact on HRQoL over time, and the additional effect on HRQoL of the often co-occurring sleep problems and psychological symptoms emphasize the need for recognition and effective treatment of itching to reduce symptom burden and improve HRQoL in dialysis patients. No individual prognosis can be derived from our study, but the findings may be used in shared decision-making. We hope that this study provided insights into and awareness of the major impact that itching can have, to enable early recognition and treatment of itching.”

Takeaway Points

1. Researchers reported results of a study in the Netherlands designed to examine the impact of itching on health-related quality of life (HRQoL) among patients on dialysis.
2. Persistent itching was reported in approximately half of the study cohort and was more common in those receiving peritoneal dialysis than those receiving hemodialysis.
3. Patients with itching had a lower physical and mental HRQoL, which remained stable during 2 years of follow-up.