Background Many people receiving palliative care have reduced oral intake during their illness, and particularly at the end of their life. Management of this can include the provision of medically assisted hydration (MAH) with the aim of improving their quality of life (QoL), prolonging their life, or both. This is an updated version of the original Cochrane Review published in Issue 2, 2008, and updated in February 2011 and March 2014. Objectives To determine the effectiveness of MAH compared with placebo and standard care, in adults receiving palliative care on their QoL and survival, and to assess for potential adverse events. Search methods We searched for studies in the Cochrane Central Register of Controlled Trials (CENTRAL), MEDLINE, Embase, CINAHL, CANCERLIT, CareSearch, Dissertation Abstracts, Science Citation Index and the reference lists of all eligible studies, key textbooks, and previous systematic reviews. The date of the latest search conducted on CENTRAL, MEDLINE, and Embase was 17 November 2022. Selection criteria We included all relevant randomised controlled trials (RCTs) of studies of MAH in adults receiving palliative care aged 18 and above. The criteria for inclusion was the comparison of MAH to placebo or standard care. Data collection and analysis Three review authors independently reviewed titles and abstracts for relevance, and two review authors extracted data and performed risk of bias assessment. The primary outcome was QoL using validated scales; secondary outcomes were survival and adverse events. For continuous outcomes, we measured the arithmetic mean and standard deviation (SD), and reported the mean difference (MD) with 95% confidence interval (CI) between groups. For dichotomous outcomes, we estimated and compared the risk ratio (RR) with 95% CIs between groups. For time-to-event data, we planned to calculate the survival time from the date of randomisation and to estimate and express the intervention effect as the hazard ratio (HR). We assessed the certainty of evidence using GRADE and created two summary of findings tables. Main results We identified one new study (200 participants), for a total of four studies included in this update (422 participants). All participants had a diagnosis of advanced cancer. With the exception of 29 participants who had a haematological malignancy, all others were solid organ cancers. Two studies each compared MAH to placebo and standard care. There were too few included studies to evaluate different subgroups, such as type of participant, intervention, timing of intervention, and study site. We considered one study to be at high risk of performance and detection bias due to lack of blinding; otherwise, risk of bias was assessed as low or unclear. MAH compared with placebo Quality of life One study measured change in QoL at one week using Functional Assessment of Cancer Therapy - General (FACT-G) (scale from 0 to 108; higher score = better QoL). No data were available from the other study. We are uncertain whether MAH improves QoL (MD 4.10, 95% CI -1.63 to 9.83; 1 study, 93 participants, very low-certainty evidence). Survival One study reported on survival from study enrolment to last date of follow-up or death. We were unable to estimate HR. No data were available from the other study. We are uncertain whether MAH improves survival (1 study, 93 participants, very low-certainty evidence). Adverse events One study reported on intensity of adverse events at two days using a numeric rating scale (scale from 0 to 10; lower score = less toxicity). No data were available from the other study. We are uncertain whether MAH leads to adverse events (injection site pain: MD 0.35, 95% CI -1.19 to 1.89; injection site swelling MD -0.59, 95% CI -1.40 to 0.22; 1 study, 49 participants, very low-certainty evidence). MAH compared with standard care Quality of life No data were available for QoL. Survival One study measured survival from randomisation to last date of follow-up at 14 days or death. No data were available from the other study. We are uncertain whether MAH improves survival (HR 0.36, 95% CI 0.22 to 0.59; 1 study, 200 participants, very low-certainty evidence). Adverse events Two studies measured adverse events at follow-up (range 2 to 14 days). We are uncertain whether MAH leads to adverse events (RR 11.62, 95% CI 1.62 to 83.41; 2 studies, 242 participants, very low-certainty evidence). Authors' conclusions Since the previous update of this review, we have found one new study. In adults receiving palliative care in the end stage of their illness, there remains insufficient evidence to determine whether MAH improves QoL or prolongs survival, compared with placebo or standard care. Given that all participants were inpatients with advanced cancer at end of life, our findings are not transferable to adults receiving palliative care in other settings, for non-cancer, dementia or neurodegenerative diseases, or for those with an extended prognosis. Clinicians will need to make decisions based on the perceived benefits and harms of MAH for each individual's circumstances, without the benefit of high-quality evidence to guide them.
