Chronic constipation may predispose affected patients to developing colorectal cancer and benign neoplasms, according to an analysis of data from a large retrospective U.S. claims database.
The risk of developing colorectal cancer was 1.78 times higher among 28,854 adults with chronic constipation than among 86,562 controls without chronic constipation, and the risk of developing benign neoplasms was 2.7 times higher in those with chronic constipation, Dr. Nicholas Talley reported in a poster at the annual meeting of the American College of Gastroenterology.
The risk of colorectal cancer and benign neoplasms among those with chronic constipation remained "consistently high" after researchers controlled for potential confounding factors, including age, gender, family history of malignancies, and other nongastrointestinal morbidities, said Dr. Talley of the University of Newcastle, Callaghan, New South Wales, Australia.
Patients included adults aged older than 18 years who received at least two diagnoses of chronic constipation 60-365 days apart between January 1999 and September 2011. Those with irritable bowel syndrome or diarrhea were excluded, as were those who did not remain enrolled in their health plans for at least 12 months from the date of their first eligible diagnosis of constipation.
The investigators matched control subjects, who had never been diagnosed with constipation and never had a prescription filled for a laxative during the observation period, with case patients in a 1:3 ratio based on year of birth, sex, and region of residence.
Patients and controls had a mean age of 61.9 years, and one-third were men. The mean observation period was nearly 4 years.
The prevalence of colorectal cancer in this study was 2.7% in the patients and 1.7% in the controls; the prevalence of benign neoplasms was 24.8% in the patients and 11.9% in the controls, Dr. Talley said.
Although the findings do not prove a causal link between chronic constipation and colorectal cancer or benign neoplasms, they do suggest a strong association, he said in a press statement.
"The postulated causal link is that longer transit times increase the duration of contact between the colonic mucosa and concentrated carcinogens such as bile acids in the lumen," he said.
This association deserves further investigation to more thoroughly explore and to better understand possible causal elements, he added.
This is particularly important because prospective cohort studies have failed to identify a similar association to that seen in this retrospective review, suggesting that those findings are affected by recall bias, he said.
While further study is needed, practitioners should be aware of the potential relationship between chronic constipation and development of colorectal cancer and benign neoplasms, and should monitor and treat patients accordingly, he concluded.
Dr. Talley received research support from Takeda Pharmaceuticals International, which supported the study. Coauthors were employed by Takeda or by Analysis Group Inc., which has received consulting fees from Takeda.