The research also showed that volume overload tended to improve over time and was associated with survival. Men and those with diabetes were more likely to have volume overload at all time points compared with women and those without diabetes, respectively.
The study, called the Initiative for Patient Outcomes in Dialysis – Peritoneal Dialysis (IPOD-PD), is the largest to date to evaluate incident peritoneal dialysis and volume overload using objective measurements, explain Wim Van Biesen, MD, PhD, of Ghent University Hospital, Belgium, and colleagues, in their article published this month in the Clinical Journal of the American Society of Nephrology.
The researchers also looked at peritoneal dialysis practices by region and found that these varied widely throughout the world.
After 3 years of follow-up, the average relative volume overload in patients was lower than at the start in participants from all regions except Latin America, where it increased.
In an accompanying Patient Voice editorial, Shari Gilford discusses her experience with peritoneal dialysis. Noting that she often retained extra fluid during the summer, she wonders whether the hot climate in much of Latin America could have affected the results.
“If there are factors other than dialysate type, dialysate concentrate, or diet that make it more difficult for patients to control their volume overload, patients need to be made aware of this,” she stressed.
“Clinicians also need to understand this additional factor when evaluating a treatment plan and training the patient,” she writes.
Peritoneal Dialysis Offers Convenience of Home Therapy
Peritoneal dialysis is often the first line of treatment for kidney failure and offers the convenience of home therapy. And it can be individualized by combining automated and manual techniques, as well as using different solutions that vary in concentration, types of solutes, and similarity to human fluids and tissues.
However, many patients who start on peritoneal dialysis experience deterioration in kidney function. In these cases, peritoneal dialysis can be a bridge to hemodialysis, which must be done in a clinic.
Patients who start on peritoneal dialysis need to monitor their activity levels, as well as the amount of salt, phosphorous, protein, potassium, and other factors in their diet that could affect the ability of the body to remove water.
The prospective cohort study took place in 135 sites in 28 countries in Western Europe, Eastern Europe, the Middle East, Asia Pacific, and Latin America. The analysis included 1054 participants who started peritoneal dialysis between January 2011 and December 2012.
At the start of peritoneal dialysis, 36% of participants had normal levels of body water, but the majority showed either moderate or severe volume overload (34% and 24%, respectively).
Researchers used bioimpedance spectroscopy to objectively measure volume status before and 1 month after starting peritoneal dialysis, and then every 3 months.
Patients are considered volume overloaded when their relative fluid volume is above the 90th percentile of a presumed healthy reference population. In this study, volume overload was defined as > 17.3% (the 75th percentile of relative volume overload at month 1 in the cohort).
Patients were followed for a minimum of 3 years and maximum of 5 years.
Volume Overload Improved for 6 Months From Baseline Then Stabilized
Over 3 years, 74% of participants dropped out of the study. A higher percentage of patients dropped out because they transferred to hemodialysis (23%) or had a kidney transplant (22%), compared with those who died (13%).
The Asia Pacific region had the lowest dropout rates, with 60% still on peritoneal dialysis after 3 years. Latin America had the highest dropout rates, with just 16% still on peritoneal dialysis after 3 years.
Before starting peritoneal dialysis, participants had an average volume overload of 1.9 L, which fell to 1.2 L in the first year, 1.46 L by year 2, and 1.46 L by year 3.
“Although volume overload is frequent in patients on kidney replacement therapy, the IPOD-PD study demonstrates that this volume overload is already present before the start of kidney replacement therapy. Volume overload tended to improve from baseline over the next 6 months and stabilized afterward,” the researchers explain.
Having a relative volume overload > 17.3% was independently linked to a 59% increased risk of death compared to participants without volume overload (adjusted hazard ratio, 1.59; 95% CI, 1.08 – 2.33). Results were adjusted for risk of transfer to hemodialysis and transplant.
In a recent meta-analysis, volume overload as assessed by bioimpedance was independently associated with mortality or hospitalization in prevalent kidney replacement therapy, they say.
“Our data confirm that this association is also present in incident kidney replacement therapy,” they write.
Results May Not Be Generalizable to All Centers
Participants in the Asia Pacific region had the best survival, despite relatively low use of hypertonic fluid or automated peritoneal dialysis. However, all but two participants in the Asia Pacific region were from South Korea, a limitation of the study, say the researchers.
The study was sponsored by Fresenius Medical Care, who produce the BCM device used to assess fluid and nutritional status. Leme Brito, De los Ríos, Gauly, and Ihle are employees of Fresenius Medical Care. Verger is a resident for the French Language Peritoneal Dialysis Registry (RDPLF), which receives financial support from Baxter, Fresenius, Theradial, and Physidia. One or more authors reports grants, personal fees, and/or speaker fees from Freseniu and/or Baxter.