| BackgroudColonoscopy is currently the gold standard in luminal diagnosis of the rectum, colonand terminal ileum. The success of colonoscopy depends on the high-quality bowelpreparation by patients. However, despite advances in bowel preparation methods, up toone-third of all colonoscopies have inadequate bowel preparation in reported series ofpatients undergoing colonoscopy. Inadequate bowel cleansing results in negativeconsequences for the examination, including incomplete visualisation of the colon,missed detection of lesions(22%-48%), procedural difficulties, prolonged procedure timeand reduced interval time for follow-up. Furthermore, inadequate bowel preparation hasbeen estimated to result in an estimated12-22%increase in overall colonoscopy cost.The effectiveness of a bowel preparation is closely linked to patient compliance with both pharmacy and dietary instructions. Previous work of Ness RM et al showedthat18%of the people with poor preparation failed to follow preparation instructions,which may be even higher because it is “socially undesirable” to report failure for apatient. Another study performed in Asia showed that non-compliance to bowelpreparation instructions, lower education level and long waiting time for colonoscopyappointment were independent risk factors for poor bowel preparation, among which theformer had the highest odd ratio (OR=4.76). A survey among doctors showed thatgastroenterologists with the highest level of inadequate bowel preparation believed thatpatients are unwilling to follow preparation instructions, struggle with the prescribed diet,and are unable to tolerate the full course of purgative. It is rationale that efforts toimprove education and maximize patient compliance during the preparatory period willenhance the efficacy of bowel preparation.Up to date, several methods had been tried to enhance patient education andcompliance on the quality of bowel preparation, while the results were inconsistent.Nurse delivered education with brochures, instructions plus educational pamphlet, anovel designed patient educational booklet and education with cartoon visual aidsincreased the quality of bowel preparation. However, other interventions, such asphotographs of “clean” and “dirty” colons in addition to writing instructions, orinstructions plus a question and answer session to provide additional information basedon responses to a questionnaire failed to improve bowel preparation quality.MethodsPatientsThis is a prospective, endoscopist-blinded, randomized, controlled study includingconsecutive outpatients undergoing colonoscopy at Endoscopy Center of Xijing Hospitalof Digestive Diseases in China. The study protocol and informed consent form wereapproved by Institutional Review Board of the Xijing Hospital, and registered withClinicalTrials.gov (NCT01584817).Outpatients aged18–75years undergoing colonoscopy and providing writteninformed consent were eligible for participation in the study. Exclusion criteria included: 1, history of colorectal surgery;2, severe colonic stricture or obstructing tumor;3, dysphagia;4, compromised swallowing reflex or mental status;5, significant gastroparesis or gastric outlet obstruction or ileus;6, known or suspected bowel obstruction or perforation;7, severe chronic renal failure (creatinine clearance<30mL/minute);8, severe congestive heart failure (New York Heart Association class III or IV);9, uncontrolled hypertension (systolic blood pressure>170mm Hg, diastolic bloodpressure>100mm Hg);10, toxic colitis or megacolon;11, dehydration;12, disturbance of electrolytes;13, pregnant or lactating women;14, patients who cannot give informed consent and those who are hemodynamicallyunstable.Patients were randomized to either the re-education or control group at the time ofappointment for colonoscopy by opening an opaque and sealed envelope. The envelopeswere randomized by using a computer-generated random numbers by an investigator(LZG) who kept the randomization key under lock until the inclusion of the last patient.At least two telephone numbers of all patients or their relatives living together wererecorded in case of failed connection latter. All patients were instructed not to tellcolonoscopists, nurses and investigators about their preparation method before, during,and after the procedure.Education on bowel preparationAt the time of an appointment for colonoscopy was made, one nurse (LJ) provideeducation about colonoscopy, including the importance of bowel preparation, the sideeffects of agents used, and the exact preparation instructions. Then a booklet with clear,written instructions was given to all patients. Patients were prescribed with polyethylene glycol electrolytes powder (PEG-ELP, each sachet containing polyethylene glycol400059g, sodium chloride1.46g, sodium sulfate5.68g, potassium chloride0.74g, sodiumbicarbonate1.68g, WanHe Pharmaceutical Co., Shenzhen, China) or sodium phosphate(SP, Fleet Phospho-soda, C.B. Fleet Company, Switzerland) for bowel preparation.Baseline demographic and clinical characteristics of all the patients were recorded.The preparation method has previously been reported with acceptable preparationcleansing rate and tolerance. Briefly, all patients were instructed to have a regular mealfor lunch and only clear liquids for dinner the day before the colonoscopy. They wereasked to drink two sachets of PEG-ELP dissolved in2L of water or90ml SP dissolved in1.5L of water at4:00-5:00AM within two hours on the same day of colonoscopy.Patients were encouraged to drink more clear liquids after purgatives for adequatehydration before colonoscopy. All colonoscopy were performed at9:00-13:00.For the patients allocated to re-education group, a telephone re-education was doneby one investigator (LH) at9:00-11:00on the day before colonoscopy. The importance ofbowel preparation, the direction for use and side effects of purgatives, the proper foodtype, and the beginning time of bowel preparation were especially emphasized. Patientswere given a telephone number and were encouraged to contact with the investigator ifthey have any question about bowel preparation. Patients in control group received thesame education and booklet on the day of appointment by the same nurse as those inre-education group, but they did not receive telephone re-education on the day beforecolonoscopy.Data collection and colonoscopyBefore colonoscopy, methods of bowel preparation, details how purgatives wereused, the food type, the beginning time of bowel preparation, side effects, sleepingquality and willingness to repeat bowel preparation were interviewed by one investigator(LH) who was not involved in the endoscopic procedure. Colonoscopies were carried outby one of five colonoscopists (ZLH, WXP, LZG, PYL and GXG) each with a minimumexperience of1000colonoscopies. The Fujinun colonoscope (CV-240, Japan) was usedfor each procedure. All colonoscopies were conducted without conscious sedation. Quality of bowel preparation, cecal intubation time, withdrawal time andcolonoscopic findings of all patients were recorded by only one investigator (LXD) whowas blinded to the methods of bowel preparation.Outcome measuresThe primary outcome was adequate bowel preparation quality at the time ofcolonoscopy defined by total Ottawa score<6. The bowel preparation was consideredinadequate if(1) inadequate visualization on colonoscopy defined by Ottawa score≥6;(2) the colonoscopy was cancelled because of poor bowel preparation or personalreasons;(3) incomplete colonoscopy. The secondary outcomes included polyp detection rate,uncompliance rate to instruction, willingness to repeat bowel preparation, cecalintubation rate, cecal intubation time and withdrawal time.Bowel cleansing was evaluated using the Ottawa scale (Gastrointestinal Endoscopy,2004,482-486). Each section of the colon, i.e. right, transverse and left is rated for levelof cleansing according to a5-point scale (0–4). In addition, the overall colonic fluid israted according to a3-point scale (0–2). As a result, the total score ranges from0to14.Non-compliance to bowel preparation was defined as improper beginning time to takepurgatives, non-adherence to dietary restrictions, the admitted failure to followinstructions including volume of bowel preparation solution to be taken, duration withinwhich the bowel preparation solution should be completed and adequate hydration.Sleeping quality was divided to excellent or good (the same to usual), fair or bad (worsethan usual) as reported previously.Sample size calculationAt the beginning of the study, a sample size calculation was performed, assuming a10%difference in the rate of colonic cleansing. The rate of adequate bowel preparation inour endoscopic center was about80%. To detect the difference with a significance level(α) of.05and a power of80%with a2-tailed test, we calculated that at least398patientswere needed for each group. However, about10%of patients may cancel their colonoscopy or have a failed colonoscopy based on our previous experience, weestimated that totally600patients would be enough for intention-to-treat detection of thedifference of primary outcome.StatisticsIntention-to-treat (ITT) analysis was used to assess primary outcome andcolonoscopic findings from all evaluable patients. Categorical variables were analysedusing Chi-square tests or Fisher’s exact test, as appropriate. Continuous variables wereexpressed as means with SD and analysed with Student’s t test. To assess factorsassociated with inadequate bowel preparation (Ottawa score≥6), multivariate analysiswas performed using variables with p values of <0.1in the univariate analysis. Analyseswere performed with SPSS software V.19.0for Windows. A p value of <0.05wasconsidered significant.ResultsPatient characteristicsFrom Feb to July in2012,1127outpatients aged18–75years undergoing unsedatedcolonoscopy were enrolled, of whom522subjects were excluded, including348metexclusion criteria and174unwilling to participate in the study. Then totally605subjectswere randomized to the re-education group (n=305) and the control group (n=300). Afterrandomization,29subjects in re-education group and27in control group cancelled theircolonoscopy appointments because of “bad” bowel preparation (2vs.6, p=0.11) orpersonal reasons (27vs.21, p=0.14). Finally,276subjects in re-education group and273in control group underwent unsedated colonoscopy. All baseline characteristics (age,BMI, education level, indication for the colonoscopy, history of constipation or surgery,et al) between the two groups were well balanced.Outcomes of bowel preparation and colonoscopyIn an intention-to-treat analyses of the primary outcome (the rate of adequate bowelpreparation) and colonoscopic findings, an adequate preparation was found in81.6%vs.70.3%of re-education and control patients, respectively (p<0.001). Polyp detection ratewas38.0%vs.24.7%in re-education and control group respectively (p<0.001). More diverticulum were found in re-education subjects (p=0.048). Colonoscopy in14subjectsof re-education group and40of control group was failed (p<0.001). The incompletecolonoscopy due to inadequate preparation was1.8%vs.10.6%in re-education andcontrol group respectively (p<0.001), while those due to technical difficulty or stricturewas not significantly different (p=0.619). The cecal intubation rate was higher inre-education group (94.9%vs.85.4%, p<0.001). Among patients with successfulcolonoscopy, the Ottawa scores were3.0±2.3in re-education group and4.9±3.2incontrol group (p<0.001). No significant differences were observed between the twogroups regarding the mean time to reach the cecum (p=0.806). However, less withdrawaltime was used in re-education group compared with control group (6.2±2.3vs.7.8±2.8min, p<0.001).Procedure of bowel preparationthe rate of uncompliance to instructions was significantly lower in re-educationgroup compared with control (9.4%vs.32.6%, p<0.001). More in detail, significantdifferences were found regarding improper begining time of bowel preparation (12vs.34,p<0.001) and improper diet restriction (11vs.58, p<0.001) between re-education andcontrol groups, while the difference of failure to follow purgative instruction (includingproper volume, duration and adequate hydration) between the two groups was notsignificant (p=0.811). More patients reported excellent or good sleep quality inre-education group compared with control (214vs.177, p=0.002). No significantdifferences were observed between the two groups in side effects (p=0.573) andwillingness to have a repeat bowel preparation (p=0.409).Factors associated with inadequate bowel preparationLogistic regression analyses were performed to identify any significant factors forinadequate bowel preparation. The factors analyzed were age, gender, BMI, history ofsurgery, bowel preparation and constipation, interval time of appointment, indication forcolonoscopy, purgative type, telephone re-education and patient compliance toinstructions. The univariate analysis indicated that constipation (OR=1.99, p=0.013),interval time from appointment to colonoscopy (OR=1.97, p=0.036), telephone re-education (OR=3.54, p<0.001), improper beginning time of bowel preparation(OR=6.68, p<0.001) and improper diet restriction (OR=4.21, p<0.001) were significantlyassociated with poor bowel preparation for colonoscopy defined by Ottawa score≥6. Themultivariate analysis revealed that constipation (OR1.96, p=0.026), telephonere-education (OR=2.43, p=0.002), improper beginning time of bowel preparation(OR=3.50, p<0.001) and improper diet restriction (OR=2.65， p=0.009) were factorssignificantly associated with poor bowel preparation for colonoscopy.StatisticsIntention-to-treat (ITT) analysis was used to assess primary outcome andcolonoscopic findings from all evaluable patients. Categorical variables were analysedusing Chi-square tests or Fisher’s exact test, as appropriate. Continuous variables wereexpressed as means with SD and analysed with Student’s t test. To assess factorsassociated with inadequate bowel preparation (Ottawa score≥6), multivariate analysiswas performed using variables with p values of <0.1in the univariate analysis. Analyseswere performed with SPSS software V.19.0for Windows. A p value of <0.05wasconsidered significant.ConclusionsTelephone re-education (TRE) about the details of bowel preparation on the daybefore colonoscopy increases the quality of bowel preparation and the rate of detection ofpolyps. Plausible explanations include a reduction in the rate of non-compliance with thestart time and diet restriction. The study identified many significant factors forinadequate bowel preparation. |
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