Clinical Outcomes of Patients undergoing Hemodialysis with Cool versus Standard Dialysate: A Systematic Review and Meta-Analysis

INTRODUCTION: Clinical practice guidelines recommend lower (35.0°C-35.5°C) instead of standard dialysate temperature (36.5°C-37.0°C) to mitigate the risk of intradialytic hypotension. However, many studies have been available since the recommendations were published. Hence, the current study aimed to provide an updated meta-analysis of clinical outcomes with cold versus standard dialysate. METHODS: This systematic review and meta-analysis included eligible articles indexed in PubMed, Cochrane Library, Web of Science, and Scopus, evaluating the effects of cooled versus standard dialysate in hemodialysis patients. The primary outcomes were intradialytic hypotension, mean arterial pressure, thermal-related discomfort, and body temperature changes. A random-effects model was used for all outcomes due to high heterogeneity (I2: intradialytic hypotension = 60%, mean arterial pressure = 72%, symptoms of discomfort = 41%, decrease in body temperature = 87%). Sensitivity analysis was performed using the "leave-one-out" approach, and the Cochrane risk-of-bias tool was used to assess study quality. A total of 31 studies were included. Pooled results indicate that cooled dialysis was associated with a lower risk of intradialytic hypotension (RR 0.67; 95% CI: 0.48-0.93; p = 0.02) and higher mean arterial pressure (MD 7.18; 95% CI: 3.79-10.58; p < 0.01). However, cooled dialysis was associated with a higher risk of discomfort (RR 1.55; 95% CI: 1.25-1.93; p < 0.01) and a significant decrease in body temperature (MD -0.29; 95% CI: -0.52 to -0.05; p = 0.02). This systematic review and meta-analysis is registered in PROSPERO under ID CRD42024589307. CONCLUSIONS: Using cooled dialysate might be a simple approach to reduce interdialytic hypotension risk and increase mean arterial pressure, albeit at the cost of patient discomfort. The limitations associated with the quality of included studies underscore the need for high-quality, multicenter studies with large/diverse study populations.