S Mihaylov,¹ C Stark,² E McColl,¹ N Steen,¹ A Vanoli,² G Rubin,^3,4 R Curless,^5–7 R Barton^5,6 and J Bond^1,7*

¹ Clinical Trials Unit, Institute of Health and Society, Newcastle University, UK
² Formerly Centre for Health Services Research, Newcastle University, UK
³ Department of Primary Care, University of Sunderland, UK
⁴ Northern Primary Care Research Network, Stockton on Tees, UK
⁵ School of Clinical Medical Sciences, Newcastle University, UK
⁶ North Tyneside General Hospital, Northumbria Healthcare Trust, UK
⁷ Institute for Ageing and Health, Newcastle University, UK

* Corresponding author

Background

Constipation may often be regarded as a trivial medical problem, but for people with chronic constipation the impact on their quality of life is considerable and the burden on healthcare resources, in terms of medical care visits, gastrointestinal-related procedures, laboratory tests and medications, is substantial.

Objectives

Trial

The aims of the Stepped Treatment of Older adults on Laxatives (STOOL) trial were:

• to investigate the clinical effectiveness and cost-effectiveness of bulk-forming, stimulant and osmotic laxatives
• to investigate the clinical effectiveness and cost-effectiveness of adding a second type of laxative agent in the treatment of patients whose constipation is not resolved by a single agent.

Add-on qualitative study

The aims of this study were:

• to define the meaning of constipation in older people from the perspective of GPs and older patients
• to investigate the use of prescribed and non-prescribed treatments for constipation in older people
• to investigate the adherence by older people to prescribed treatments for constipation.

Methods

Trial

Design

A multicentre pragmatic, factorial randomised controlled trial with economic evaluation.

Health technologies being assessed

Six stepped-treatment strategies using three classes of laxatives: bulk, stimulant and osmotic preparations, singly and in combination.

Setting

General practices in north-east England.

Participants

People aged 55 years or over with chronic constipation living in private households. Participants were identified as patients who had been prescribed laxatives three or more times in the previous 12 months, or with a recorded diagnosis of chronic functional constipation, or who had been prescribed a laxative continuously for the previous 12 months.

Outcome measures

The primary outcome was the constipation-specific Patient Assessment of Constipation – Symptoms/Patient Assessment of Constipation – Quality of Life. Secondary outcomes included EuroQoL 5 Dimensions, reported number of bowel movements per week, the presence/absence of the other Rome II criteria for constipation, adverse effects of treatment and relapse rates.

Qualitative study

In-depth interviews with older patients (target populations as for the trial) and their GPs, and focus-group interviews with practice and community nurses were undertaken using a purposive maximum variation sampling strategy (older people: variation by age, gender, socio-economic status, experience of constipation and use of different constipation treatments; health professionals: variation by age, gender, professional training, specialist interest and characteristics of the practice).

Results

Trial

Recruitment to the trial was difficult and the trial was closed after recruiting 19 participants.

Qualitative study

GP participants provided patient-centred definitions that focused on the idea of a change from the norm as defined by the individual patient and 'textbook definitions' that focused on reduced frequency of defecation associated with a range of unpleasant sensations and other clinical symptoms. Nurses' definitions of constipation included both a patient-centred perspective and the description of particular symptoms associated with constipation. Older participants defined constipation in terms of frequency of bowel movements and changes in normal bowel routine.

Older participants perceived that constipation is linked to specific diseases, medical conditions or health problems; caused by the consumption of specific medications or surgical procedures; caused by diet or eating habits; part of the ageing process; due to not going to the toilet when having the urge to defecate; hereditary; caused by stress or worry; and caused by environmental exposure. GP participants suggested that constipation is due to changes in diet and lifestyle; the physiology and degenerative processes of ageing; and the iatrogenic impact of opiate medications. Nurse participants identified that constipation is linked to decreased mobility, decreased food intake, decreased fluid intake and consumption of certain medications.

For many older people their constipation emerged as a problem over a period of time; for some the 'condition' had existed for many years. Self-management of constipation had typically been their first response to the symptoms and continued once professional help had been sought. Older participants had a wide experience of different management strategies and treatments for constipation, and at the time of the study had firm preferences about the laxatives they would use.

GP participants recognised the experience and use of laxatives of their patients. They exhibited strong personal preferences for different laxatives, often prescribing them in combination. Nurses were more likely than GPs to treat and prevent constipation using non-laxative measures; these included providing advice on appropriate dietary changes, increasing fluid intake and, if possible, encouraging exercise and mobility.

Conclusions

Constipation means different things to different people. There is little shared understanding between patients and professionals about 'normal' bowel function. There is little consensus in general practice regarding the optimum management strategies for chronic constipation and there is continuing uncertainty about the most effective strategies to use.

Chronic constipation is seen as less important than other conditions prevalent in general practice (e.g. diabetes) because it is not an agreed management target within national frameworks. Consequently, practitioners had little interest in constipation as a research topic.

Patient preferences and the absence of patient equipoise formed an enormous barrier to the recruitment of patients in the implementation of the STOOL trial. The successful involvement of patients and professionals in health technology assessments requires obvious uncertainty about treatment and management options and a clear interest in the topic by all parties.

The implementation of the Human Rights Act in the post-Alder Hey Inquiry environment and the increased stringencies resulting from the enactment of the EU Clinical Trials Directive have increased the barriers to health services research more widely. The implementation of research governance and ethical review processes in response to this new research environment has not allowed an appropriate balance between the rights of the individual and the collective rights of society, and typically does not involve a risk-based approach. Ethical guidance that opting-out recruitment strategies were too coercive and that recruitment of all participants should use opting-in strategies is a considerable barrier to study recruitment.

Recommendations for further research

The following studies could be undertaken in the future:

• studies to investigate different methods of recruitment within the constraints of current ethical guidelines on 'opting in'
• studies to identify barriers and facilitators to recruitment to complex trials in general
• patient preference trials and natural cohort observational studies to investigate the effectiveness or cost-effectiveness of different laxatives and treatment strategies in the management of chronic constipation.

Publication

Mihaylov S, Stark C, McColl E, Steen N, Vanoli A, Rubin G, et al. Stepped treatment of older adults on laxatives. The STOOL trial. Health Technol Assess 2008;12(13).

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