Better health-related quality of life is associated with prolonged survival and reduced hospitalization risk among dialysis-dependent chronic kidney disease patients: a historical cohort study

Abstract

Rationale & objective: End-stage kidney disease (ESKD) negatively affects patients' physical, emotional, and social functioning. Furthermore, adjustment to dialysis require substantial lifestyle changes that may further impact on patients physical and emotional well-being. However, the relationship between Health-Related Quality of life impairment with future adverse outcomes in dialysis is not well characterized. Our study aims to investigate the relationship between Health-Related Quality of Life (HRQoL) and patients' survival and hospitalization rates within a large European dialysis network.

Methods: A historical cohort study was conducted to evaluate association of HRQoL with hospitalization and mortality rates over a 12-month follow-up period. Patients responded to a self-administered survey as part of a Continuous Quality Improvement Program implemented in clinics affiliated with the Spanish FMC-Nephrocare organization. Health-Related Quality of Life (HRQoL) was measured with the KDQOL-36. Potential confounders included socio-demographic characteristics, comorbidities, biochemical parameters, dialysis treatment. We used Cox's Proportional Hazard regression to assess the hazard of death and Logistic Regression to assess the likelihood of hospital admissions during 12-month follow-up period.

Results: A total of 2280 (51.5%) completed the self-administrated survey, and 1838 patients met the inclusion/exclusion criteria of the study. Higher HRQoL scores were associated with significantly lower mortality and hospitalization risk. Risk estimates were robust to adjustment for potential confounders.

Conclusions: Several dimensions of HRQoL are associated with patient-centered outcomes (i.e., mortality and hospitalizations at 1 year). Patient-Reported Outcomes contribute unique pieces of information characterizing patients' health. Residual confounding cannot be fully ruled out; moreover, the high attrition rate could result in selection bias, which may limit the generalizability of the findings to a broader population.

Keywords: Dialysis; End Stage Kidney Disease; Health-Related Quality of Life; Hospitalization; Mortality.

Fig. 1

Flow chart of the study sample. Flow chart of the study cohort of patients depicting all the exclusion criteria applied to the collected sample

Fig. 2

Distribution of KDQoL-36 scores in the study sample. (a) Histogram of SF-12 physical composite score (PCS) values; (b) histogram of SF-12 mental composite score (MCS) values; (c) histogram of burden of kidney disease (BKD) values; (d) histogram of symptoms of kidney disease (SKD) values; (e) histogram of effects of kidney disease (EKD) values; (f) histogram of Kidney Disease Scale (KSS) values, a summary score derived from the 24 disease specific items of the KDQoL-36

Fig. 3

Plots of the relationship between survival and KDQoL-36 scores in the study sample. The relationship between survival and KDQoL-36 scores was estimated through Cox regression analysis. Dashed lines outline 95% confidence interval of the estimated values. (a) BKD, burden of kidney disease; (b) EKD, effects of kidney disease; (c) SKD, symptoms of kidney disease; (d) PCS, physical composite score; (e) MCS, mental composite score; (f) KSS, Kidney Disease Scale, a summary score derived from the 24 disease specific items of the KDQoL-36

Fig. 4

Plots of the relationship between the number of hospitalizations and KDQoL-36 scores in the study sample. The relationship between hospitalization incidence and KDQoL-36 scores was estimated through logistic regression analysis. Dashed lines outline 95% confidence interval of the estimated values. (a) BKD, burden of kidney disease; (b) EKD, effects of kidney disease; (c) SKD, symptoms of kidney disease; (d) PCS, physical composite score; (e) MCS, mental composite score; (f) KSS, Kidney Disease Scale, a summary score derived from the 24 disease specific items of the KDQoL-36

Fig. 5

Plots of the relationship between the number of hospitalization days and KDQoL-36 scores in the study sample. The relationship between hospitalization days and KDQoL-36 scores was estimated through negative binomial regression analysis. Dashed lines outline 95% confidence interval of the estimated values. (a) BKD, burden of kidney disease; (b) EKD, effects of kidney disease; (c) SKD, symptoms of kidney disease; (d) PCS, physical composite score; (e) MCS, mental composite score; (f) KSS, Kidney Disease Scale, a summary score derived from the 24 disease specific items of the KDQoL-36