IS OLD STILL WORTH ITS WEIGHT IN GOLD? COMPARISON OF THE EFFECT OF BIOIMPEDANCE VERSUS CLINICAL ASSESSMENT ON SHORT-TERM OUTCOMES OF VOLUME ASSESSMENT IN MAINTENANCE HEMODIALYSIS PATIENTS

Introduction:

Volume assessment has been important since the time hemodialysis became a modality of Renal Replacement Therapy. Volume overload as well as volume depletion have been shown to be associated with increased cardiovascular morbidity and mortality. Recently other objective methods have become available like bioimpedance for a better assessment of volume status. However it has its own set of limitations. But how does it stand against the age-old method of meticulous clinical assessment in terms of episodes of clinical significance like symptomatic volume overload/depletion?

Methods:

Here, we divided the patients into 2 groups, where 1 group had their dry-weight adjusted with the routinely practiced clinical examination (n = 43). Monthly pre-HD bioimpedance (done with the Fresenius BCM) was performed but not used to adjust the dry-weight. While in the other arm, we adjusted the dry-weight to the pre-HD bioimpedance derived dry weight, which was done monthly as well as when an event of symptomatic volume overload/depletion developed in the patients of this arm. We compared the hydration status and episodes of symptomatic volume overload/depletion requiring revision of dry-weight in each arm over a period of 6 months. Patients were matched for other factors that can lead to these events, like anemia, cardiac function, nutrition, clearance, and frequency of hemodialysis (twice vs. thrice weekly). We excluded patients with active malignancy, pacemaker implantation, limb amputation, and metallic implants, as these can affect bioimpedance analysis.

Results:

Based on the statistical equation, sample size of 22 in each group was required. Out of the enrolled patients (n = 43 in each group), 37 patients in the clinical arm and 36 patients in the bioimpedance arm completed the study period. The patients did not have any statistically significant difference in terms of dialysis frequency, dialysis vintage, serum albumin, hemoglobin, or LV systolic function. A statistically significant difference was present between the two groups in terms of normohydration status achieved as measured by bioimpedance. A higher number of patients were in normohydration limits in the bioimpedance arm. However, there was no statistically significant difference in terms of symptomatic volume overload/volume depletion events. These parameters are discussed in detail in the charts and graphs attached herewith. So, in Conclusion: Regular,  meticulous clinical examination is equivalent to periodic bioimpedance analysis for volume management in hemodialysis patients in terms of clinically significant episodes. These short-term events, though, are surrogates of hard outcomes like cardiovascular morbidity and mortality.

Conclusions:

The proportion of patients in the normohydration (+/- 1.1 liter) range in the bioimpedance arm is significantly higher than the clinical arm at the end of the study period. However, the episodes as well as proportion of patients developing symptomatic volume overload/depletion do not differ significantly between the two groups. This can be attributed to the regular clinical examination for assessment of dry-weight in our dialysis unit. However, in centers where clinician rounds do not happen on a regular basis, periodic bioimpedance can be a useful tool for the assessment of dry-weight and hydration status.

I have no potential conflict of interest to disclose.

I did not use generative AI and AI-assisted technologies in the writing process.