Key messages
- In people with central neurological diseases, some non-drug treatments, such as probiotics and abdominal massage, may improve self-reported symptoms of constipation, while others, such as holistic nursing assessment, may improve self-reported symptoms of faecal incontinence (FI).
- The evidence is very uncertain whether some non-drug treatments (probiotics and nursing assessment) have any effect on people’s quality of life, the time they need to spend on bowel care, or their risk of harmful or unwanted effects from the treatment.
- Further research, including specific core outcome measures, is needed in this area. The development of outcome measures needs to depend upon the key quality of life symptoms that are important to this group of individuals.
How do constipation and FI affect people with central neurological diseases?
People with central neurological diseases, such as Parkinson’s disease, spinal cord injury, multiple sclerosis and stroke, often suffer from bowel problems. These include constipation and FI, with some people experiencing both conditions. It can be very difficult to manage constipation without causing faecal leakage or stop it without causing constipation. People with central neurological diseases often need to spend more time emptying their bowels, which can cause great anxiety, distress and reduce their quality of life.
How are constipation and FI managed in people with central neurological diseases?
Constipation and FI in people with central neurological diseases can be managed in several ways. Non-drug options for bowel management include conservative treatments, such as making dietary modifications (e.g. taking probiotics or prebiotics). Physical therapies include exercise, massaging the area around the belly, or using water to clear the bowel of faeces. Surgery is also a non-drug treatment option.
What did we want to find out?
We wanted to find out how effective non-drug interventions were for treating people with constipation, FI, or both, as a result of a central neurological disease.
What did we do?
We searched for studies that investigated conservative management options, physical therapies or surgery compared with either no treatment, usual care (care delivered at home or in a hospital by a healthcare professional) or “dummy” treatments that do not contain any medicine in people with constipation, FI, or both, as a result of having a central neurological disease. We compared and summarised the results of these studies and rated our confidence in those results, based on factors such as the study methods and their size.
What did we find?
We found 25 studies involving 1598 people with a central neurological disease and either constipation, FI, or both. Eight studies included people with Parkinson's disease, seven included people with spinal cord injury, five included people with stroke, two included participants with multiple sclerosis, one with participants with spina bifida, one with people with dementia and one included people with severe learning disabilities. Nearly all the studies took place in high-income countries. Two of the included studies were sponsored by industry and three did not report funding sources. One study declared that the authors had received no financial support. The remaining studies were funded either by research grants, hospitals or local authorities, charities, or non-profit organisations.
Main results
We found 13 studies comparing conservative management options with usual care, no active treatment or placebo. Conservative management options may result in a large reduction in self-reported faecal incontinence symptoms, and they may also improve constipation symptoms. Additionally, conservative interventions may lead to a reduction in the average time taken on bowel care. However, the evidence is very uncertain whether conservative interventions are effective in improving people’s condition-specific well-being, or how many side effects these treatments might lead to. None of the studies reported on the Neurogenic Bowel Dysfunction Score, a tool used to measure bowel dysfunction in people with central neurological diseases.
We found 12 studies that compared physical therapies to usual care, no active treatment or placebo. Physical therapies may make little to no difference in symptoms of faecal incontinence but may lead to a moderate improvement in constipation. However, physical therapies may make little to no difference to the Neurogenic Bowel Dysfunction Score. The evidence is very uncertain whether physical therapies are effective in improving people’s condition-specific well-being, the amount of time they need to spend on bowel care or how many side effects these treatments might lead to.
What are the limitations of the evidence?
Generally, we have little confidence in the evidence because of how studies were conducted. In many studies, it was possible for people to know what treatment they were getting, which may have affected results, and many studies had issues with the way they reported results. Additionally, studies often had very few people participating in them. There is a lack of uniform measurements within the research that would allow different pieces of research to be compared and information on the potential side effects of these treatments was very limited.
How up to date is this evidence?
The evidence is up to date to 27 March 2023.
There remains little research on this common and, for patients, very significant issue of bowel management. The available evidence is almost uniformly of low methodological quality. The clinical significance of some of the research findings presented here is difficult to interpret, not least because each intervention has only been addressed in individual trials, against control rather than compared against each other, and the interventions are very different from each other.
Understanding whether there is a clinically-meaningful difference from the results of available trials is largely hampered by the lack of uniform outcome measures. This is due to an absence of core outcome sets, and development of these needs to be a research priority to allow studies to be compared directly. Some studies used validated constipation, incontinence or condition-specific measures; however, others used unvalidated analogue scales to report effectiveness. Some studies did not use any patient-reported outcomes and focused on physiological outcome measures, which is of relatively limited significance in terms of clinical implementation.
There was evidence in favour of some conservative interventions, but these findings need to be confirmed by larger, well-designed controlled trials, which should include evaluation of the acceptability of the intervention to patients and the effect on their quality of life.
People with central neurological disease or injury have a much higher risk of both faecal incontinence (FI) and constipation than the general population. There is often a fine line between the two symptoms, with management intended to ameliorate one risking precipitating the other. Bowel problems are observed to be the cause of much anxiety and may reduce quality of life in these people. Current bowel management is largely empirical, with a limited research base. The review is relevant to individuals with any disease directly and chronically affecting the central nervous system (post-traumatic, degenerative, ischaemic or neoplastic), such as multiple sclerosis, spinal cord injury, cerebrovascular disease, Parkinson's disease and Alzheimer's disease.
This is an update of a Cochrane Review first published in 2001 and subsequently updated in 2003, 2006 and 2014.
To assess the effects of conservative, physical and surgical interventions for managing FI and constipation in people with a neurological disease or injury affecting the central nervous system.
We searched the Cochrane Incontinence Specialised Register (searched 27 March 2023), which includes searches of the Cochrane Central Register of Controlled Trials (CENTRAL), MEDLINE, MEDLINE In-Process, MEDLINE Epub Ahead of Print, ClinicalTrials.gov, WHO ICTRP as well as handsearching of journals and conference proceedings; and all reference lists of relevant articles.
We included randomised, quasi-randomised (where allocation is not strictly random), cross-over and cluster-randomised trials evaluating any type of conservative, physical or surgical intervention against placebo, usual care or no intervention for the management of FI and constipation in people with central neurological disease or injury.
At least two review authors independently assessed the risk of bias in eligible trials using Cochrane's 'Risk of bias' tool and independently extracted data from the included trials using a range of prespecified outcome measures. We produced summary of findings tables for our main outcome measures and assessed the certainty of the evidence using GRADE.
We included 25 studies with 1598 participants. The studies were generally at high risk of bias due to lack of blinding of participants and personnel to the intervention. Half of the included studies were also at high risk of bias in terms of selective reporting. Outcomes were often reported heterogeneously across studies, making it difficult to pool data. We did not find enough evidence to be able to analyse the effects of interventions on individual central neurological diseases. Additionally, very few studies reported on the primary outcomes of self-reported improvement in FI or constipation, or Neurogenic Bowel Dysfunction Score.
Conservative interventions compared with usual care, no active treatment or placebo
Thirteen studies assessed this comparison. The interventions included assessment-based nursing, holistic nursing, probiotics, psyllium, faecal microbiota transplantation, and a stepwise protocol of increasingly invasive evacuation methods.
Conservative interventions may result in a large improvement in faecal incontinence (standardised mean difference (SMD) -1.85, 95% confidence interval (CI) -3.47 to -0.23; 3 studies; n = 410; low-certainty evidence). We interpreted SMD ≥ 0.80 as a large effect.
It was not possible to pool all data from studies that assessed improvement in constipation, but the evidence suggested that conservative interventions may improve constipation symptoms (data not pooled; 8 studies; n = 612; low-certainty evidence). Conservative interventions may lead to a reduction in mean time taken on bowel care (data not pooled; 5 studies; n = 526; low-certainty evidence). The evidence is uncertain about the effects of conservative interventions on condition-specific quality of life and adverse events. Neurogenic Bowel Dysfunction Score was not reported.
Physical therapy compared with usual care, no active treatment or placebo
Twelve studies assessed this comparison. The interventions included massage therapy, standing, osteopathic manipulative treatment, electrical stimulation, transanal irrigation, and conventional physical therapy with visceral mobilisation.
Physical therapies may make little to no difference to self-reported faecal continence assessed using the St Mark's Faecal Incontinence Score, where the minimally important difference is five, or the Cleveland Constipation Score (MD -2.60, 95% CI -4.91 to -0.29; 3 studies; n = 155; low-certainty evidence). Physical therapies may result in a moderate improvement in constipation symptoms (SMD -0.62, 95% CI -1.10 to -0.14; 9 studies; n = 431; low-certainty evidence). We interpreted SMD ≥ 0.5 as a moderate effect. However, physical therapies may make little to no difference in Neurogenic Bowel Dysfunction Score as the minimally important difference for this tool is 3 (MD -1.94, 95% CI -3.36 to -0.51; 7 studies; n = 358; low-certainty evidence). We are very uncertain about the effects of physical therapies on the time spent on bowel care, condition-specific quality of life and adverse effects (all very low-certainty evidence).
Surgical interventions compared with usual care, no active treatment or placebo
No studies were found for surgical interventions that met the inclusion criteria for this review.