Development and evaluation of a risk assessment tool to improve clinical triage accuracy for colonoscopic investigations

Diagnostic accuracy of fecal calprotectin in predicting significant gastrointestinal diseases

Background and Aim

It is often unreliable to triage patients for timely endoscopic investigations based on symptoms alone. We need an objective assessment to differentiate between organic gastrointestinal diseases and functional bowel symptoms. We evaluated the diagnostic accuracy of fecal calprotectin (FC) in predicting organic gastrointestinal diseases.

Methods

In a prospective observational study, consecutive patients referred for colonoscopy to the Department of Medicine and Geriatrics at the Kwong Wah Hospital in Hong Kong were recruited. Stool samples were collected within 24 h before colonoscopy. FC was measured by a commercial kit. Upper endoscopy investigations were then proceeded if normal colonoscopy but elevated FC.

Results

Two hundred and seventy out of 429 patients had FC above 50 μg/g. Eighty‐six out of 270 with elevated FC had significant colonoscopy pathological findings. The sensitivity, specificity, positive predictive value (PPV), and negative predictive value (NPV) of FC test for diagnosing a significant organic colonoscopy or upper endoscopy disease were 91.7, 55.6, 57.0, and 91.2%, respectively. The NPV of FC for colorectal cancer, high risk polyp, and colon inflammation were 98.7, 96.2, and 98.1%, respectively. The NPV of FC in the condition of altered bowel habit or abdominal pain in predicting colorectal cancer and inflammation were 93.8 and 100%, respectively.

Conclusions

FC is a reliable marker of ruling out organic bowel diseases. A single negative FC test could be used as a triage tool to prioritize the need and urgency of further investigation, particularly in the setting of altered bowel habits and abdominal pain.

Validation of Australian and Victorian guidelines for colonoscopy triage

BACKGROUND AND AIMS

This study aimed to assess the diagnostic performance of National and Victorian colonoscopy triage guidelines and potential redistribution of triage categories.

METHODS

Diagnostic validation study comparing colonoscopy triage guidelines against a reference colonoscopy dataset.

PARTICIPANTS

reference dataset of 2,378 colonoscopies from 1 October 2014 to 30 June 2016. Comparison with triage categorisation determined using: National Cancer Council Australia guidelines; Victorian triage guidelines; Optimal Cancer Care Pathways recommendations.

MAIN OUTCOME MEASURES

i. Proportion of colonoscopies assigned to each triage category; ii. detection rate (proportion of cancers assigned to triage Category 1); iii. conversion rate (proportion of triage Category 1 colonoscopies which diagnose a cancer).

RESULTS

After adjusting for data absent in referrals, the National and Victorian guidelines reduced the proportion of Category 1 colonoscopies compared with the reference triage (National 76.3% vs 58.6%; 95% CI for difference 15.0 - 20.3% p<0.0001. Victorian 76.3% vs 66.3%; 95% CI for difference 7.4 - 12.6% p<0.0001). Victorian guidelines were associated with the highest detection rate (91.4%) and a conversion rate of 5.4% although the number of cancers limited the power to detect significant differences on these metrics. There was a higher proportion of unclassifiable colonoscopies using the National guidelines than the Victorian ones due to their focus on symptomatic indications.

CONCLUSIONS

The Victorian guidelines could reduce the proportion of Category 1 colonoscopies by 10% without reducing conversion or detection rates. This would require improvements in the quality of referrals and ordering faecal occult blood tests in 6% of symptomatic patients. This article is protected by copyright. All rights reserved.

Evaluating a risk assessment tool to improve triaging of patients to colonoscopies

BACKGROUND

Colonoscopy is the gold standard in the diagnosis of significant bowel disease (SBD), including colorectal cancer, high-risk adenoma and inflammatory bowel disease. As the demand for colonoscopy services is placing significant pressure on hospital resources, new solutions are needed to manage patients more efficiently and effectively.

AIM

We investigated the impact of using a risk assessment tool (RAT) to improve selection of patients for colonoscopy procedures to detect SBD.

METHODS

A hybrid simulation model was constructed to replicate the current patient triage bookings and waiting times in a large metropolitan hospital. The model used data on 327 patients who were retrospectively assessed for risk of SBD. Risk assessment incorporated blood and faecal immunochemical test results, gender and age in addition to patient symptoms. The model was calibrated over 12 months to current outcomes and was compared with the RAT and a third scenario where low-risk patients did not proceed to a colonoscopy. One-way sensitivity analyses were undertaken.

RESULTS

Using the RAT was expected to shorten waiting times by 153 days for moderately-urgent patients and 138 days for non-urgent patients. If low-risk patients did not proceed to colonoscopy, waiting times were expected to reduce for patients with SBD by 17 days producing cost-savings of AU$373 824 through avoided colonoscopies.

CONCLUSIONS

A hybrid model that combines patient-level characteristics with hospital-level resource constraints can demonstrate improved efficiency in a hospital clinic. Further research on risk assessment is required to improve quality patient care and reduce low-value service delivery.