Effect of opioids on constipation in critically ill patients: A meta-analysis

This meta-analysis evaluated the effect of opioids on constipation in ICU patients. Systematic review and meta-analysis. PubMed, Embase, Cochrane Library, China National Knowledge Infrastructure (CNKI), and Wanfang DATA databases. Random or fixed-effects meta-analyses were used. Subgroup analysis was performed according to the definition of constipation (three vs. six days), opioids (fentanyl vs. morphine), study design (prospective vs. retrospective), adjustment of confounders (No vs. Yes), and patient's age (adults vs. children). We used sensitivity analysis to test the robustness of results with significant statistical heterogeneity. Seven studies (2264 patients) were included. Opioid use in ICU patients was associated with an increased risk of constipation (relative risk [RR]=1.14; 95% confidence interval [CI]=1.05 to 1.24; I2=49.8%). Subgroup analysis further showed that adjustment form, category of opioid, study design, and patient's age significantly influenced the relationship between opioid use and the risk of constipation. Sensitivity analysis confirmed the robustness of pooled results. Opioids significantly increase the risk of constipation in critically ill patients, especially children. It is worth noting that the adjustment of the constipation definition used for ICU significantly influenced the relationship between opioid use and the risk of constipation. Therefore, It is necessary to clearly define ICU constipation and conduct time-based layered treatment. Additional prospective studies are needed to investigate the consistent definition of ICU constipation.