Sterile water injections for analgesia in renal colic: a meta-analysis of level 1 evidence

To evaluate the effectiveness of Sterile water injections (SWIs) for acute pain relief in renal colic. This study was conducted in accordance with the Preferred Reporting items for Systematic Reviews and Meta-Analyses. MEDLINE, CINAHL, Web of Science and Cochrane were searched to identify randomised controlled trials (RCTs) comparing SWIs with placebo or other analgesics in renal colic patients. Data were pooled and analysed using random effects modelling with 95% confidence intervals (CIs). Six RCTs including 1322 renal colic patients were included, with 466 (35.2%) receiving SWIs. Patients receiving SWIs had comparable demographics and presenting features to the control groups, with control medications ranging from placebos, non-steroidal anti-inflammatories, and opioids. Self-reported pain scores at 30 min following intervention were lower in SWI than placebo (MD = - 4.63, 95% CI: - 5.16, - 4.10, P < 0.001) and other analgesics (MD = - 0.36, 95% CI: - 0.52, - 0.21, P < 0.001). The use of rescue analgesia was lower in those receiving SWIs compared to placebo (OR = 0.24, 95% CI: 0.10, 0.59, P = 0.002) and other analgesics (OR = 0.46, 95% CI: 0.29, 0.74, P = 0.001). No significant side effects were attributed to SWI use. SWIs demonstrated superior pain relief and reduced rescue analgesia requirements, compared to placebo and standard treatment, offering a promising alternative for patients where traditional options are unsuitable.