PREVALENCE AND RISK FACTORS OF INTRADIALYTIC HYPERTENSION IN MALAYSIAN HAEMODIALYSIS PATIENTS: A MUTLI-CENTRE OBSERVATIONAL STUDY

Introduction:

Intradialytic hypertension (IDH) is a complication among haemodialysis patients, linked to increased cardiovascular morbidity and mortality. Despite its significance, the prevalence and contributing factors of IDH in the Malaysian dialysis population remain unexplored. The aetiology involves factors like extracellular fluid overload, electrolyte imbalances, and activation of the sympathetic nervous system and the renin-angiotensin-aldosterone system (RAAS). Given demographic variations, understanding IDH in Malaysia is important. This study aims to determine the prevalence of IDH in Malaysian haemodialysis patients and explore potential contributing factors to improve management strategies.

Methods:

A prospective cross-sectional study was conducted among 80 haemodialysis patients at three dialysis centres (one in-hospital, two standalone) over 6 months in 2023. Patients were reviewed for six consecutive dialysis sessions to assess IDH, defined as an episode of increase in systolic blood pressure (SBP) >10 mmHg from pre- to post-dialysis, with post-dialysis SBP >150 mmHg, instead of the KDIGO definition of IDH in at least four out of six sessions. All patients received a dialysate sodium concentration of 140 mmol/L and a temperature of 37°C, with calcium concentrations of 1.5 mmol/L (22.5%), 1.25 mmol/L (42.5%), and 1.0 mmol/L (35%). Data collected included demographics, comorbidities, dialysis parameters, antihypertensive use, interdialytic weight gain (IDWG), ESA dosing, and laboratory results. Mann-Whitney U and Chi-square tests compared variables between groups.

Results:

Among the 80 patients, 35% (n = 28) had at least one episode of IDH during six sessions, though none met the KDIGO definition of IDH in at least four out of six sessions. The mean age in the IDH group was 57.6 ± 11.2 years, compared to 55 ± 14 years in the non-IDH group (p = 0.39). The median dialysis vintage was longer in the IDH group (7 years, IQR 9) versus the non-IDH group (3.5 years, IQR 8), though not statistically significant (p = 0.29). Antihypertensive use differed, with 42.9% of the IDH group on beta-blockers versus 23.1% in the non-IDH group, suggesting a trend towards significance (p = 0.06). Other antihypertensives (ACE inhibitors/ARBs, calcium channel blockers, alpha-blockers) were similar between groups. The median IDWG was 2.20 kg (IQR 1.0) in the IDH group and 2.18 kg (IQR 1.1) in the non-IDH group (p = 1.0), and the median ESA dose was 1833 IU (IQR 1333 IU) in both groups (p = 1.0). These findings suggest that dialysis vintage and beta-blocker use may warrant further investigation in larger cohorts.

Conclusions:

In this cohort, 35% of patients experienced at least one IDH episode, though none met the KDIGO definition. The lack of patients meeting the guideline criteria may reflect well-controlled baseline blood pressure in the cohort. The small sample size could limit the ability to detect significant differences. Minimal IDWG suggests extracellular fluid overload is not a primary factor, unlike in other studies and the higher prevalence of beta-blocker use in the IDH group raises questions about antihypertensive medication types and their dialysability, warranting further study. This contradicts the finding of a recent meta-analysis by Hartono et al., which showed significant blood pressure reduction during dialysis with beta-blockers usage. Overall, these findings suggest the need for larger studies to identify significant clinical characteristics contributing to IDH, enabling the development of better management strategies tailored to local practices and patient characteristics.

I have no potential conflict of interest to disclose.

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