Illness Perceptions in Patients on Predialysis Care: Associations With Time Until Start of Dialysis and Decline of Kidney Function.

Objectives: Illness perceptions in patients with end-stage renal disease are associated with nonadherence and increased mortality. However, no data are available regarding the relationship between illness perceptions and accelerated disease progression in predialysis patients.

Methods: A total of 416 incident predialysis patients participating in a prospective cohort (PREPARE-2, Predialysis Patient Record-2) completed the Revised Illness Perception Questionnaire at the start of specialized predialysis care. The association between illness perceptions and time until start of dialysis was investigated using Cox regression models. Linear mixed modeling was used to test associations between illness perceptions and change of kidney function during predialysis care. Adjustments were made for sociodemographic, clinical, and biochemical factors.

Results: Five illness perceptions were associated with disease progression. Dialysis started earlier and kidney function declined faster (ml/min per 1.73 m/y) in patients who perceived their kidney disease as being cyclical in nature (adjusted hazard ratio [HRadj] = 1.32 [95% confidence interval {CI} = 1.11-1.56]; adjusted additional change = -0.64 [95% CI = -1.16 to -0.13]), having many negative consequences (HRadj = 1.47 [95% CI = 1.18-1.85]; adjusted additional change = -0.67 [-1.30 to -0.04]) and causing negative feelings (HRadj = 1.21 [95% CI = 1.03-1.42]; adjusted additional change = -0.65 [95% CI = -1.13 to -0.16]). In addition, kidney function declined faster in patients who perceived that their kidney disease cannot be personally controlled (adjusted additional change = -0.69 [95% CI = -1.31 to -0.09]) and who perceived that they did not fully understand their kidney disease (adjusted additional change = -0.53 [-1.05 to -0.01]).

Conclusions: Stronger negative perceptions of illness at the start of predialysis care are a marker for accelerated disease progression. Detecting illness perceptions in predialysis patients may provide opportunities to intervene and slow down disease progression.