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Hyperkalemia (HK) is one of the most frequently observed hydro electrolyte disorders in patients (Pts) with severe renal dysfunction and especially in those under maintenance hemodialysis (HD). Its relevance lies in the potential risk for the development of serious arrhythmias and increased mortality. Missing HD sessions and even after the long interdialytic period (LIP) increase the risk of its occurrence. The main aim of this study was to assess the impact of the LIP on serum potassium concentration [K + ] and verify if these differ from those usually recorded at midweek (MW). The secondary objective was to define the prevalence of mild HK (K + > 5.1 mEq/L) and moderate-severe HK (MSHK - K + > 6.0 mEq/L) in this population of HD patients from a local public hospital
Ambispective cross-sectional study in adult Pts on thrice-a-week HD (4 hours/session) for > 6 months, who were stable and adherent to treatment without having missed any HD in the last month, were not on cathartics or intestinal K + binders and were normoglycemic at the time of blood sampling. The MW sample belonged to the preceding monthly routine laboratory and the LIP to a sample taken on Monday or Tuesday of that current month without this being prearranged or known in advance by Pts. In order to analyze the prevalence and recurrence of hyperkalemia, laboratory results from the last 6 to 12 months (n: 495 registers) prior to the LIP sample were retrospectively evaluated. All data are expressed as mean (sd) or count (percent).
The paired “t” test was used to examine the difference in MW and LIP potassium concentration. P values < 0.05 were considered statistically significant.
Data from 48 HD-requiring CKD Pts (29 men), aged 24.1 - 73.1 years, most of them with diabetic nephropathy (DN n: 10), non-DBT glomerular disease, (n: 14) HTN (n: 10) or unknown origin (n: 10) with HD vintage from 6 to 137 months were studied. HK, defined as serum K > 5.1
mmol/L was present in 44 individuals (91.7%) while 28 (58.3%) displayed MSHK. Recurrent HK was observed in 40 participants (83.3%). K + levels (mEq/L) were similar in MW (5.3 ± 1.0) and in LIP (5.5 ± 1.2 mEq/l) p: NS (figure 1). Forty-one Pts (85.4%) presented MW HK while MSHK was observed in 28 of them (58.3%) at MW and in 15 Pts (31.3%) in LIP.
Despite some individuals showed dramatically higher levels of K+ after LIP, the absence of significant differences between MW and LIP serum K + in this cohort of HD Pts would suggest a fairly good adherence to the care and medical recommendations issued, the relevance of which acquire greater importance in the presence of a longer interdialytic period.
On the other hand, the prevalence as well as the recurrence of HK and MSHK in this cohort of HD-requiring individuals is higher than that reported in the literature but similar to that obtained in our previous registers.
Given that the sample size is relatively small, additional studies in a larger number of individuals and involving multiple HD facilities might help to understand this important and still non-enough defined issue and to customize strategies in order to reduce the risk of such potentially devastating electrolyte abnormality.