Varying PD-practices between different regions impacted volume status, according to a published study. In addition, volume overload — present even before the start of kidney replacement therapy — was associated with specific patient characteristics and higher mortality risk.
“It is postulated that the active management of volume overload may reduce risk of technique failure (transfer to hemodialysis) and improve survival in PD patients,” Wim Van Biesen, MD, PhD, of the department of internal medicine, renal division, at University Hospital Ghent in Belgium, and colleagues wrote. “However, most of the strategies used to reduce volume overload also carry a risk for undesired side effects. It is thus also important to take into account the strategies used to maintain euvolemia. With this in mind, the Initiative for Patient Outcomes in Dialysis-Peritoneal Dialysis (IPOD-PD) study investigates volume status in an incident patient population to relate patient characteristics and practice patterns over a long-term follow-up to volume status and patient relevant outcomes.”
Researchers conducted a prospective cohort study of 1,054 participants — enrolled shortly before PD treatment was started — from 135 study centers in 28 countries (36% of participants euvolemic at the start of PD; 33% with moderate volume overload; 24% with severe volume overload). Countries were grouped into the regions of Western Europe, Eastern Europe and Middle East, Asia Pacific and Latin America.
Researchers collected clinical data, including laboratory parameters, planned PD prescription, volume status (using bioimpedance spectroscopy) and medication, 3 days or fewer before the start of PD therapy, 3 months after the start of PD and again every 3 months until the participant dropped out (changed kidney replacement modality, terminated study for other reasons or died). Associations between factors at 1 month and relative volume status, along with the impact of these factors on the course of volume status during the next 5 months, were analyzed. The association between variables measured at baseline, 1 month and 3 years and time to death was also considered.
Researchers found that, of all participants, 74% dropped out, with 13% dying, 23% transferring to hemodialysis and 22% having transplantation. The dropout rate was lowest in the Asia Pacific region, with 60% of participants remaining on PD after 3 years (26%, 23% and 16% remained on PD in Western Europe, Eastern Europe and Middle East and Latin America, respectively).
In addition, researchers observed that relative volume overload greater than 17.3% at 1 month was independently associated with increased risk of death (adjusted HR = 1.59) during the 3-year observation period compared with relative volume overload of no more than 17.3%. Increasing age, presence of diabetes and male gender were risk factors for more frequent volume overload.
Varying PD-practices between different regions impacted volume status.
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Finally, researchers noted that volume overload tended to improve in most regions with the mean relative volume overload lower than at baseline in participants from all regions except those from Latin America where it increased.
“There were substantial differences in volume status between regions and in practices with a potential impact on volume status,” the researchers concluded. “In Asia Pacific, the usage of hypertonic bags and polyglucose was low. Despite this, the initial volume overload could be successfully reduced. In contrast, in Latin America, volume overload even increased over time despite a high percentage using hypertonic solutions after 2 and 3 years. An influence on volume overload by the use of hypertonic exchanges might be only limited and possibly superimposed by differences in adherence to salt and fluid restriction. Anyhow, our results indicate that it is possible to maintain good volume status even without the use of hypertonic exchanges, polyglucose or automated PD.”
In a related editorial, Shari Gilford, member of the Renal Support Network and a kidney transplant recipient, wrote: “In light of my own observations of the relationship between climate and fluid retention, the results of the study immediately raised a question in my mind. Why did patients in Latin America have a different outcome than other regions included in the study? If there are factors other than dialysate type, dialysate concentrate or diet which make it more difficult for patients to control their volume overload, patients need to be made aware of this. I wonder if the year-round hotter climate of Latin America, as opposed to most other regions in the study which have cold seasons, could have been a factor for fluid overload leading to increased mortality. Continued study of this variable might improve outcomes for PD patients who live in warmer climates.” – by Melissa J. Webb
Disclosures: Van Biesen reports receiving travel grants and speaker fees from Fresenius Medical Care and Baxter Healthcare. Please see the study for all other authors’ relevant financial disclosures.