Course of symptoms and health-related quality of life during specialized pre-dialysis care

Abstract

Background: Concerns are present on the limited value of renal function alone in defining the optimal moment to start dialysis. Disease-related symptoms and health-related quality of life (HRQOL) may have additional clinical value in defining this moment, but little is known about how these parameters change during pre-dialysis care. The aims of our study were to describe the course of symptoms and HRQOL during pre-dialysis care and to investigate their association with poor health outcomes.

Methods: In the prospective PREPARE-2 cohort, incident patients starting specialized pre-dialysis care were included when referred to one of the 25 participating Dutch outpatient clinics (2004-2011). In the present analysis, 436 patients with data available on symptoms and HRQOL were included. Clinical data, symptoms (revised illness perception questionnaire), and HRQOL (short form-36 questionnaire; physical and mental summary score) were collected every 6-month interval. A time-dependent Cox proportional hazard model was used to associate symptoms and HRQOL with the combined poor health outcome (i.e. starting dialysis, receiving a kidney transplant, and death).

Results: All symptoms increased, especially fatigue and loss of strength, and both the physical and mental summary score decreased over time, with the most pronounced change during the last 6-12 months of follow-up. Furthermore, each additional symptom (adjusted HR 1.04 (95% CI, 1.00-1.09)) and each 3-point lower physical and mental summary score (adjusted HR 1.04 (1.02-1.06) and 1.04 (1.02-1.06) respectively) were associated with a higher risk of reaching the combined poor health outcome within the subsequent 6 months.

Conclusions: The number of symptoms increased and both the physical and mental HRQOL score decreased during pre-dialysis care and these changes were associated with starting dialysis, receiving a kidney transplant, and death. These results may indicate that symptoms and HRQOL are good markers for the medical condition and disease stage of pre-dialysis patients.

Figure 1. Course of symptoms during pre-dialysis care.

The course of the total number of symptoms is presented for the total population (A) and stratified by the type of endpoint reached (combined poor health outcome; dialysis/transplantation/death, or end of follow-up/other endpoint, B). The black and grey dots indicate the mean and the error bars indicate the standard error of the mean (SEM). The time in months before reaching an endpoint is presented on the x-axis (−12 means that the measurement was 7–12 months before reaching an endpoint, −18 means 13–18 months etc). On the y-axis, the mean (SEM) total number of symptoms is presented, which can range from 0 to 12.

Figure 2. Course of HRQOL during pre-dialysis care.

The course of the physical and mental summary score are presented for the total population (A) and stratified by the type of endpoint reached (combined poor health outcome; dialysis/transplantation/death, or end of follow-up/other endpoint, B). The black and grey dots indicate the mean and the error bars indicate the standard error of the mean (SEM). The time in months before reaching an endpoint is presented on the x-axis (−12 means that the measurement was 7–12 months before the moment of reaching an endpoint, −18 means 13–18 months etc). On the y-axis, the mean (SEM) score from the SF-36 questionnaire is presented (separately for the physical and mental summary measure), which can range from 0 to 100.

Figure 3. Course of eGFR and CrCl during pre-dialysis care.

The course of eGFR and CrCl are presented for the total population (A) and stratified by the type of endpoint reached (combined poor health outcome; dialysis/transplantation/death, or end of follow-up/other endpoint, B). The black and grey dots indicate the mean and the error bars indicate the standard error of the mean (SEM). The time in months before reaching an endpoint is presented on the x-axis (−12 means that the measurement was 7–12 months before the moment of reaching an endpoint, −18 means 13–18 months etc). On the left y-axis, the mean (SEM) eGFR (ml/min/1.73 m²) is presented, and on the right y-axis the mean (SEM) CrCl (ml/min/1.73 m²).