Self-reported Pruritus and Clinical, Dialysis-Related, and Patient-Reported Outcomes in Hemodialysis Patients

Abstract

Rationale & objective: Chronic kidney disease (CKD)-associated pruritus, generalized itching related to CKD, affects many aspects of hemodialysis patients' lives. However, information regarding the relationship between pruritus and several key outcomes in hemodialysis patients remains limited.

Study design: Prospective cohort.

Setting & participants: 23,264 hemodialysis patients from 21 countries in the Dialysis Outcomes and Practice Patterns Study (DOPPS) phases 4 to 6 (2009-2018).

Exposure: Pruritus severity, based on self-reported degree to which patients were bothered by itchy skin (5-category ordinal scale from "not at all" to "extremely").

Outcomes: Clinical, dialysis-related, and patient-reported outcomes.

Analytical approach: Cox regression for time-to-event outcomes and modified Poisson regression for binary outcomes, adjusted for potential confounders.

Results: The proportion of patients at least moderately bothered by pruritus was 37%, and 7% were extremely bothered. Compared with the reference group ("not at all"), the adjusted mortality HR for patients extremely bothered by pruritus was 1.24 (95% CI, 1.08-1.41). Rates of cardiovascular and infection-related deaths and hospitalizations were also higher for patients extremely versus not at all bothered by pruritus (HR range, 1.17-1.44). Patients extremely bothered by pruritus were also more likely to withdraw from dialysis and miss hemodialysis sessions and were less likely to be employed. Strong monotonic associations were observed between pruritus severity and longer recovery time from a hemodialysis session, lower physical and mental quality of life, increased depressive symptoms, and poorer sleep quality.

Limitations: Residual confounding, recall bias, nonresponse bias.

Conclusions: Our findings demonstrate how diverse and far-reaching poor outcomes are for patients who experience CKD-associated pruritus, specifically those with more severe pruritus. There is need for change in practice patterns internationally to effectively identify and treat patients with pruritus to reduce symptom burden and improve quality of life and possibly even survival.

Keywords: hemodialysis; patient-reported outcomes; pruritus; quality of life.

Graphical abstract

Figure 1

Flow chart of inclusion/exclusion criteria for primary analysis and list of secondary outcomes. ∗Number of eligible patients for each secondary analysis varies based on data availability of each outcome variable, as detailed in Methods. Abbreviations: CES-D, Center for Epidemiologic Studies-Depression; DOPPS, Dialysis Outcomes and Practice Patterns Study; HD, hemodialysis; MCS, Mental Component Summary; PCS, Physical Component Summary; SF-12, 12-Item Short Form Health Survey.

Figure 2

Self-reported pruritus, by country. Abbreviations: A/NZ, Australia/New Zealand; Bel, Belgium; Can, Canada; Chi, China; Fra, France; GCC, Gulf Cooperation Council countries (Bahrain, Kuwait, Oman, Qatar, Saudi Arabia, United Arab Emirates); Ger, Germany; Ita, Italy; Jpn, Japan; Rus, Russia; Spa, Spain; Swe, Sweden; Tur, Turkey; UK, United Kingdom; US, United States.

Figure 3

Association of pruritus with all-cause and cause-specific (A) mortality and (B) hospitalization. Cox regression models stratified by Dialysis Outcomes and Practice Patterns Study (DOPPS) phase and country; adjustments: age, sex, end-stage kidney disease vintage, 15 comorbid conditions, postdialysis weight, albumin level, hemoglobin level, phosphorus level, and catheter use.

Figure 4

Pruritus and dialysis-related outcomes. Adjustments: age, sex, end-stage kidney disease vintage, 15 comorbid conditions, postdialysis weight, albumin level, hemoglobin level, phosphorus level, and catheter use. (A) Cox model stratified by Dialysis Outcomes and Practice Patterns Study (DOPPS) phase and country; (B) modified Poisson regression with log-link and robust variance estimator, additionally adjusted for DOPPS phase and country.

Figure 5

Pruritus and patient-reported outcomes. Adjustments: Dialysis Outcomes and Practice Patterns Study (DOPPS) phase, country, age, sex, end-stage kidney disease vintage, 15 comorbid conditions, postdialysis weight, albumin level, hemoglobin level, phosphorus level, and catheter use. (A) Linear mixed models with random facility intercept to account for clustering; (B) modified Poisson regression with log-link and robust variance estimator. Abbreviations: PCS/MCS, Physical/Mental Component Summary, derived from the 12-Item Short Form Health Survey.