Medically assisted hydration for adult palliative care patients Stable (no update expected for reasons given in 'What's new')

Abstract

Background

Many palliative care patients have reduced oral intake during their illness. The management of this can include the provision of medically assisted hydration with the aim of prolonging the life of a patient, improving their quality of life, or both. This is an updated version of the original Cochrane review published in Issue 2, 2008, and updated in February 2011.

Objectives

To determine the effect of medically assisted hydration in palliative care patients on their quality and length of life.

Search methods

We identified studies by searching 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 March 2014.

Selection criteria

All relevant randomised controlled trials (RCTs) or prospective controlled studies of medically assisted hydration in palliative care patients.

Data collection and analysis

We identified six relevant studies for this update. These included three RCTs (222 participants), and three prospective controlled trials (360 participants). Two review authors independently assessed the studies for quality and validity. The small number of studies and the heterogeneity of the data meant that a quantitative analysis was not possible, so we included a description of the main findings.

Main results

One study found that sedation and myoclonus (involuntary contractions of muscles) scores were improved more in the intervention group. Another study found that dehydration was significantly higher in the non‐hydration group, but that some fluid retention symptoms (pleural effusion, peripheral oedema and ascites) were significantly higher in the hydration group. The other four studies (including the three RCTs) did not show significant differences in outcomes between the two groups. The only study that had survival as an outcome found no difference in survival between the hydration and control arms.

Authors' conclusions

Since the last version of this review, we found one new study. The studies published do not show a significant benefit in the use of medically assisted hydration in palliative care patients; however, there are insufficient good‐quality studies to inform definitive recommendations for practice with regard to the use of medically assisted hydration in palliative care patients.

Author(s)

Phillip Good, Russell Richard, William Syrmis, Sue Jenkins‐Marsh, Jane Stephens

Abstract

Plain language summary

Medically assisted hydration to assist palliative care patients 

Background 

It is common for palliative care patients to have reduced fluid intake during their illness. Management of this condition includes discussion with the patient, family and staff involved, and may include the provision of fluids with medical assistance. This can be performed using a small plastic tube inserted into a vein or under the skin, or via a tube inserted into the stomach. It is unknown whether this treatment helps people to feel better or live longer.

Study characteristics 

We searched the international literature for randomised controlled trials looking at the effects of medically assisted hydration in adults receiving palliative care. Randomised controlled trials allocate patients to one of two or more treatment groups in a random manner and provide the most accurate information on the best treatment. We conducted the searches in April 2013 and March 2014.

Key results and quality of evidence 

We found only six studies looking at this issue. The studies did not show a significant benefit in the use of medically assisted hydration in palliative care patients; however, there are insufficient good‐quality studies to make any definitive recommendations. . As a result, it is not possible to define the benefits and harms of this treatment clearly.

Author(s)

Phillip Good, Russell Richard, William Syrmis, Sue Jenkins‐Marsh, Jane Stephens

Reviewer's Conclusions

Authors' conclusions 

Implications for practice 

Since the last version of this review, we found one new study. The studies published show no significant benefit in the use of medically assisted hydration in palliative care patients; however, there are insufficient good quality studies to inform definitive recommendations for practice with regard to the use of medically assisted hydration in palliative care patients.

There are a few good‐quality studies that examine the benefits and harms of the use of medically assisted hydration in this population. Two randomised controlled trials (RCTs) in this review had a short duration of hydration (two days) to assess effects, and no information on the effect hydration may have on survival. The other RCT was of longer duration, and found little difference in outcomes between the hydration and control groups. It also found no difference in survival between the two groups. The results from one included study suggest that there may be some benefit in terms of improvement in sedation and myoclonus, but another study showed that there may be some harm in terms of worsening of fluid retention symptoms (pleural effusion, peripheral oedema and ascites) and these results need to be taken in the context of low participant numbers, limited palliative care settings and narrow palliative care patient population groups. Clinicians will need to make a decision based on the perceived benefits and harms of medically assisted hydration in individual patient circumstances, without the benefit of high‐quality evidence to guide them.

Implications for research 

Study design

High‐quality studies in the palliative care population have proven very difficult to perform successfully. The difficulty of research in a vulnerable population such as palliative care patients has been discussed in the literature. These difficulties start with consent, are followed by recruitment, elimination of confounders and end with retention of participants throughout a study period (Rinck 1997). There have been some innovative suggestions about how to overcome the issue of consent (Rees 2003), and some studies have used this methodology with success (Breitbart 2002). Other studies have shown that large numbers are not always needed to show a benefit (Abernethy 2003), but the question of safety is difficult to answer due to the small numbers of participants commonly being found in palliative care studies. This has been illustrated by the fact that there were only two RCTs of a high quality in this review. Despite being methodologically sound, the results were limited by lack of recruitment. Perhaps of more interest was that the issue of medically assisted hydration in palliative care patients causes such divergent views, yet there are so few studies to guide clinical practice properly. As well as examining further RCTs in this area, the evidence base will be improved with at least more prospective controlled trials.

Participant groups

The studies in this review had narrowly defined patient populations. Palliative care is performed in hospitals, inpatient palliative care units and in the community. Studies need to be performed in all these areas to allow external validity to different palliative care populations. It would also be helpful to define at what stage of their illness participants are being given medically assisted hydration. The reasons and aims of hydration in the last few days/weeks of life may be very different to those participants with a longer prognosis. An agreed diagnostic criteria for hydration status is essential for future trials, both to assess at entry and to assess as an outcome. In addition, all the participants in the included studies had advanced cancer, and it is important to examine medically assisted hydration in non‐cancer populations. The prospective prediction of prognosis is difficult, and it may be better to stratify participants according to their performance status.

Interventions

Medically assisted hydration can be given by many different routes. The studies included in this review used either the subcutaneous or intravenous route. We found no studies that used the enteral route for hydration. Further studies are needed to determine the optimum route and dose.

Outcomes

It is important that clinically relevant outcomes are clearly defined and are the most clinically useful. In this patient population, this should include symptoms (such as sedation, fatigue, hallucinations and myoclonus) as well as diagnoses such as delirium. Despite much controversy about the effect medically assisted hydration may have on length of life, it was only included as an outcome in one study in this review. Future studies should include the survival of participants as an outcome. It is equally important that adverse events are well defined so that the risk of treatment can be balanced against any benefits.

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