Modifiable practices associated with sudden death among hemodialysis patients in the Dialysis Outcomes and Practice Patterns Study

Abstract

Background and objectives: Sudden death is common in hemodialysis patients, but whether modifiable practices affect the risk of sudden death remains unclear.

Design, setting, participants, & measurements: This study analyzed 37,765 participants in 12 countries in the Dialysis Outcomes and Practice Patterns Study to explore the association of the following practices with sudden death (due to cardiac arrhythmia, cardiac arrest, and/or hyperkalemia): treatment time [TT] <210 minutes, Kt/V <1.2, ultrafiltration volume >5.7% of postdialysis weight, low dialysate potassium [K(D) <3]), and prescription of Q wave/T wave interval-prolonging drugs. Cox regression was used to estimate effects on mortality, adjusting for potential confounders. An instrumental variable approach was used to further control for unmeasured patient-level confounding.

Results: There were 9046 deaths, 26% of which were sudden (crude mortality rate, 15.3/100 patient-years; median follow-up, 1.59 years). Associations with sudden death included hazard ratios of 1.13 for short TT, 1.15 for large ultrafiltration volume, and 1.10 for low Kt/V. Compared with K(D) ≥3 mEq/L, the sudden death rate was higher for K(D) ≤1.5 and K(D)=2-2.5 mEq/L. The instrumental variable approach yielded generally consistent findings. The sudden death rate was elevated for patients taking amiodarone, but not other Q wave/T wave interval-prolonging drugs.

Conclusions: This study identified modifiable dialysis practices associated with higher risk of sudden death, including short TT, large ultrafiltration volume, and low K(D). Because K(D) <3 mEq/L is common and easy to change, K(D) tailoring may prevent some sudden deaths. This hypothesis merits testing in clinical trials.

Figure 1.

Cause of death by country. (A) Observed cause of death by country (n=9046 deaths), as reported. (B) Cause of death by country (n=6610 deaths), with 2436 deaths excluded due to missing/unknown causes. (C) Cause of death by country (n=9046), with imputed causes of death for 2436 with missing/unknown causes. Data from the following phases of the of the Dialysis Outcomes and Practice Patterns Study: phase 1, n=15,589 patients from 308 facilities in seven countries, including France, Germany, Italy, Japan, Spain, the United Kingdom, and the United States; phase 2, n=11,675 patients from 322 facilities in 12 countries, including the above-mentioned countries as well as Australia, New Zealand, Belgium, Canada, and Sweden; and phase 3, n=10,501 patients from 300 facilities in the same 12 countries as in phase 2. US, United States; IT, Italy; JP, Japan; FR, France; BE, Belgium; ANZ, Australia and New Zealand; CA, Canada; GE, Germany; UK, United Kingdom; SP, Spain; SW, Sweden; CV, cardiovascular.

Figure 2.

Facility percentage of patients with short treatment time, low Kt/V, large ultrafiltration volume and low dialysate potassium, by country. Data from phase 3 of the Dialysis Outcomes and Practice Patterns Study, which included 298 facilities with ≥10 patients with each treatment of interest. ANZ, Australia and New Zealand; BE, Belgium; CA, Canada; FR, France; GE, Germany; IT, Italy; JP, Japan; SP, Spain; SW, Sweden; US, United States; UK, United Kingdom; UF, ultrafiltration.

Figure 3.

Association of treatment practices with sudden death. Adjusted for variables listed in Table 1 and in the Materials and Methods, stratified by phase and country and accounted for facility clustering. *Used predicted treatment from first stage. IV, instrumental variable; UF, ultrafiltration; 95% CI, 95% confidence interval.