The pattern of choosing dialysis modality and related mortality outcomes in Korea: a national population-based study

Abstract

Background/aims: Since comorbidities are major determinants of modality choice, and also interact with dialysis modality on mortality outcomes, we examined the pattern of modality choice according to comorbidities and then evaluated how such choices affected mortality in incident dialysis patients.

Methods: We analyzed 32,280 incident dialysis patients in Korea. Patterns in initial dialysis choice were assessed by multivariate logistic regression analyses. Multivariate Poisson regression analyses were performed to evaluate the effects of interactions between comorbidities and dialysis modality on mortality and to quantify these interactions using the synergy factor.

Results: Prior histories of myocardial infarction (p = 0.031), diabetes (p = 0.001), and congestive heart failure (p = 0.003) were independent factors favoring the initiation with peritoneal dialysis (PD), but were associated with increased mortality with PD. In contrast, a history of cerebrovascular disease and 1-year increase in age favored initiation with hemodialysis (HD) and were related to a survival benefit with HD (p < 0.001, both). While favoring initiation with HD, having Medical Aid (p = 0.001) and male gender (p = 0.047) were related to increased mortality with HD. Furthermore, although the severity of comorbidities did not inf luence dialysis modality choice, mortality in incident PD patients was significantly higher compared to that in HD patients as the severity of comorbidities increased (p for trend < 0.001).

Conclusions: Some comorbidities exerted independent effects on initial choice of dialysis modality, but this choice did not always lead to the best results. Further analyses of the pattern of choosing dialysis modality according to baseline comorbid conditions and related consequent mortality outcomes are needed.

Keywords: Comorbidity; Mortality; Peritoneal dialysis; Renal dialysis.

Figure 1.

Comparisons of multivariable-adjusted mortality risks between peritoneal dialysis (PD) and hemodialysis (HD) by subgroups (adjusted hazard ratios [HRs] and 95% confidence intervals [CIs] for mortality by multivariable-adjusted Cox proportional hazard regression analyses). NHI, National Health Insurance; MA, Medical Aid; DM, diabetes mellitus; MI, myocardial infarction; CHF, congestive heart failure; PAD, peripheral artery disease; CVD, cerebrovascular disease; CPD, chronic pulmonary disease; PUD, peptic ulcer disease; LD, liver disease.

Figure 2.

The pattern of choosing dialysis modality according to baseline comorbid conditions and related mortality outcomes. Black bars: multivariable-adjusted likelihood to choose dialysis modality according to baseline comorbid conditions in all incident dialysis patients (adjusted odds ratios and 95% confidence intervals [CIs] by multivariable-adjusted logistic regression analysis for choosing each dialysis modality). Red bars: multivariable-adjusted likelihood to experience more harm from one modality than from the other modality in all incident dialysis patients (adjusted synergy factors and 95% CIs based on a multiplicative interaction between initial dialysis modality and baseline comorbid conditions on mortality). Red shaded area: the pattern of choice for dialysis modality in this condition consequently increased the mortality risk (p < 0.05). Blue shaded area: the pattern of choice for dialysis modality in this condition consequently conferred the survival benefit (p < 0.05). MA, Medical Aid; NHI, National Health Insurance; HD, hemodialysis; PD, peritoneal dialysis.

Figure 3.

Multivariable-adjusted likelihood to choose peritoneal dialysis (PD) as an initial dialysis modality according to the number and severity of comorbidities measured by Charlson comorbidity index (CCI) in all incident dialysis patients (adjusted odds ratios and 95% confidence intervals by multivariable-adjusted logistic regression analysis for choosing each dialysis modality). HD, hemodialysis.

Figure 4.

Multivariable-adjusted likelihood to experience more harm with peritoneal dialysis (PD) as an initial dialysis modality according to the number and severity of comorbidities measured by Charlson comorbidity index (CCI) in all incident dialysis patients (adjusted synergy factors and 95% confidence intervals based on a multiplicative interaction between initial dialysis modality and the number/ severity of comorbidities on mortality). HD, hemodialysis. ^aThe increases in the number of comorbidities (≥ 1 comorbidities vs. no comorbidity) and CCI scores significantly associated with the increase in mortality when accompanied by PD as an initial dialysis modality (p < 0.05).