How useful is docusate in patients at risk for constipation? A systematic review of the evidence in the chronically ill.

The effectiveness of docusate for constipation has not been studied in the terminally ill. Controversy also exists concerning its effectiveness in the chronically ill. Because chronically ill patients and terminally ill patients have several risk factors for constipation in common, we undertook a systematic review of prospective controlled trials of oral docusate in the chronically ill to clarify the utility of this drug in populations with advanced disease. The data sources were Medline 1966-April 1997, CINAHL 1982-April 1997, Current Contents August 1996-April 1997, Cochrane Library, a hand search of Index Medicus 1940-1966, three palliative care journals, references in relevant articles and texts, and direct contact with experts. Prospective controlled trials evaluating oral docusate in humans with chronic illness and identifiable risk factors for, or preexisting, constipation were selected. Only materials abstracted in English or French were considered. Information was collected by two independent reviewers and included patient demographic data, study design, dose of docusate, outcomes of stool consistency, stool frequency, need for other laxatives, and assessment of methodologic and reporting quality. Of nine identified studies, four were eligible. These incorporated three different designs and sample sizes that ranged from 15 to 74. Quality assessment scores were low (range 0.46-0.52 with a perfect score being 1.0). Three studies were flawed in blinding of treatment allocation and the use of co-interventions. All studies showed a small trend toward increased stool frequency on docusate. Because of significant clinical heterogeneity in the identified studies, pooled data analysis was not feasible. At present, the use of docusate for constipation in palliative care is based on inadequate experimental evidence. Randomized controlled trials with chronically ill patients and patients with advanced disease are needed to determine its role in prevention and treatment of constipation.