Predictors of Colonoscopy Non-attendance and the Efficacy of a SMS Reminder to Reduce Non-attendance Rate

The Chinese University of Hong Kong logo

The Chinese University of Hong Kong




Ultilization of Out-patient Colonoscopy Service


Other: Non-SMS reminder
Other: SMS reminder

Study type


Funder types



NAC Study

Details and patient eligibility


To conduct a prospective randomized controlled study to identify predictors for colonoscopy non-attendance and examine the efficacy of SMS reminder to improve the non-attendance rate.

Full description

Implementation of colorectal screening programs has been shown to decrease, the incidence of colorectal cancer due to the early detection and removal of pre-cancerous colonic polyps. Colonoscopy is therefore one of the most common medical procedures performed in the United States with 14 million procedures performed in 2003. Aside from screening, colonoscopy is also essential for other aspects of colorectal cancer management including post-resection surveillance and palliative treatments. Use of computer simulation models showed that the demand for colonoscopy in the United States exceeds current capacity regardless of screening strategy. The incidence of colorectal cancer has been increasing in Hong Kong and has been associated with progressive increase in the colonoscopy waiting times in the public health care system. The progressive increase in the demand for colonoscopy therefore poses a significant burden on the healthcare systems of all developed countries. Methods to increase the capacity and efficiency of the colonoscopy service are needed.

Non-attendance rates of gastrointestinal endoscopy appointments may range from 12% to 27% 5-6 and results in inefficient use of healthcare resources, delay in diagnosis and an increase in waiting times. Adams et al. conducted a prospective cohort study which showed that younger age, long waiting times and referral from a non-gastroenterologist were significantly associated with non-attendance. In an another prospective cohort study, Sola-Vera et al. also showed that the waiting time and source of referral were independent predictive factors for non-attendance 7. Studies on gynecological endoscopy non-attendance revealed that predictors of non-attendance include unemployment, current smokers, younger age, long follow up periods, lower social class, lower education levels and lack of understanding of the endoscopic procedure 8-10.

Telephone reminders have been used to improve non-attendance rates; Adams et al. had decreased the non-attendance rate from 12.2% to 9% after introduction of telephone reminder 1 week prior to the examination. The Mayo clinic open-access endoscopy system, which incorporates a standard telephone reminder 3-7 days prior to the procedure, has a non-attendance rate of only 4.1%.


2,225 patients




18+ years old


No Healthy Volunteers

Inclusion criteria

  • All patients referred for an outpatient colonoscopy at the Alice Ho Miu Ling Nethersole Hospital Combined Endoscopy Unit

Exclusion criteria

  • Age ≤ 18
  • Lack of informed consent

Trial design

Primary purpose

Health Services Research



Interventional model

Parallel Assignment


Single Blind

2,225 participants in 2 patient groups

SMS reminder
Active Comparator group
A text message reminder via Short Message Service (SMS) will be sent to remind subjects 7-10 days before his colonoscopy appointment
Other: SMS reminder
Other: Non-SMS reminder
Non-SMS reminder
No Intervention group
No text message reminder via Short Message Service (SMS) will be sent

Trial contacts and locations



Data sourced from

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