A predictive model of longitudinal, patient-specific colonoscopy results

Cost-effectiveness Analysis of Colorectal Cancer Screening Strategies Using Active Learning and Monte Carlo Simulation

INTRODUCTION

Detection of colorectal cancer (CRC) in the early stages through available screening tests increases the patient's survival chances. Multimodal screening policies can benefit patients by providing more diverse screening options and balancing the risks and benefits of screening tests. We investigate the cost-effectiveness of a wide variety of multimodal CRC screening policies.

METHODS

We developed a Monte Carlo simulation framework to model CRC dynamics. We proposed an innovative calibration process using machine learning models to estimate age- and size-specific adenomatous polyps' progression and regression rates. The proposed approach significantly expedites the model parameter space search.

RESULTS

Two multimodal proposed policies (i.e., 1] colonoscopy at 50 y and fecal occult blood test annually between 60 and 75 y and 2] colonoscopy at 50 and 60 y and fecal immunochemical test annually between 70 and 75 y) are identified as efficient frontier policies. Both policies are cost-effective at a willingness to pay of $50,000. Sensitivity analyses were performed to assess the sensitivity of results to a change in screening test costs as well as adherence behavior. The sensitivity analysis results suggest that the proposed policies are mostly robust to the considered changes in screening test costs, as there is a significant overlap between the efficient frontier policies of the baseline and the sensitivity analysis cases. However, the efficient frontier policies were more sensitive to changes in adherence behavior.

CONCLUSION

Generally, combining stool-based tests with visual tests will benefit patients with higher life expectancy and a lower expected cost compared with unimodal screening policies. Colonoscopy at younger ages (when the colonoscopy complication risk is lower) and stool-based tests at older ages are shown to be more effective.

HIGHLIGHTS

We propose a detailed Markov model to capture the colorectal cancer (CRC) dynamics. The proposed Markov model presents the detailed dynamics of adenomas progression to CRC.We use more than 44,000 colonoscopy reports and available data in the literature to calibrate the proposed Markov model using an innovative approach that leverages machine learning models to expedite the calibration process.We investigate the cost-effectiveness of a wide variety of multimodal CRC screening policies and compare their performances with the current in-practice policies.

Evaluating the Cost-Effective Use of Follow-Up Colonoscopy Based on Screening Findings and Age

Introduction

Colorectal cancer (CRC), if not detected early, can be costly and detrimental to one's health. Colonoscopy can identify CRC early as well as prevent the disease. The benefit of screening colonoscopy has been established, but the optimal frequency of follow-up colonoscopy is unknown and may vary based on findings from colonoscopy screening and patient age.

Methods

A partially observed Markov process (POMP) was used to simulate the effects of follow-up colonoscopy on the development of CRC. The POMP uses adenoma and CRC growth models to calculate the probability of a patient having colorectal adenomas and CRC. Then, based on mortality, quality of life, and the costs associated with diagnosis, treatment, and surveillance of colorectal cancer, the overall costs and increase in quality-adjusted life years (QALYs) are calculated for follow-up colonoscopy scenarios.

Results

At the $100,000/QALY gained threshold, only one follow-up colonoscopy is cost-effective only after screening at age 50 years. The optimal follow-up is 8.5 years, which gives 84.0 QALYs gained/10,000 persons. No follow-up colonoscopy was cost-effective at the $50,000 and $75,000/QALY gained thresholds. The intervals were insensitive to the findings at screening colonoscopy.

Conclusion

Follow-up colonoscopy is cost-effective following screening at age 50 years but not if screening occurs later. Following screening at age 50 years, the optimal follow-up interval is close to the currently recommended 10 years for an average risk screening but does not vary by colonoscopy result.

Improving the work efficiency of healthcare-associated infection surveillance using electronic medical records

In this study, we developed an integrated hospital-associated urinary tract infection (HAUTI) surveillance information system (called iHAUTISIS) based on existing electronic medical records (EMR) systems for improving the work efficiency of infection control professionals (ICPs) in a 730-bed, tertiary-care teaching hospital in Taiwan. The iHAUTISIS can automatically collect data relevant to HAUTI surveillance from the different EMR systems, and provides a visualization dashboard that helps ICPs make better surveillance plans and facilitates their surveillance work. In order to measure the system performance, we also created a generic model for comparing the ICPs' work efficiency when using existing electronic culture-based surveillance information system (eCBSIS) and iHAUTISIS, respectively. This model can demonstrate a patient's state (unsuspected, suspected, and confirmed) and corresponding time spent on surveillance tasks performed by ICPs for the patient in that state. The study results showed that the iHAUTISIS performed better than the eCBSIS in terms of ICPs' time cost. It reduced the time by 73.27 s, when using iHAUTISIS (114.26 s) and eCBSIS (187.53 s), for each patient on average. With increased adoption of EMR systems, the development of the integrated HAI surveillance information systems would be more and more cost-effective. Moreover, the iHAUTISIS adopted web-based technology that enables ICPs to online access patient's surveillance information using laptops or mobile devices. Therefore, our system can further facilitate the HAI surveillance and reduce ICPs' surveillance workloads.

A risk index for advanced neoplasia on the second surveillance colonoscopy in patients with previous adenomatous polyps

BACKGROUND

Predicting the risk of advanced colorectal neoplasia on the second surveillance colonoscopy could help tailor surveillance.

OBJECTIVE

To derive and validate a risk index for advanced neoplasia on the second surveillance colonoscopy.

DESIGN

Retrospective cohort.

SETTING

Single-specialty practice; Veterans Affairs Medical Center.

PATIENTS

A total of 965 patients with baseline adenomatous polyps, 2 surveillance colonoscopies, and no reported family history of colorectal cancer; validation cohort of 372.

INTERVENTIONS

Multivariable logistic regression including demographics and previous colonoscopy results; derivation and validation of a risk index.

MAIN OUTCOME MEASUREMENTS

Advanced adenoma (≥1 cm in size, villous histology, or high-grade dysplasia) on the second surveillance colonoscopy.

RESULTS

Mean age was 57.8 ± 9.8 years, 62% were men, and 36% had an advanced adenoma on the index colonoscopy. Associated with advanced adenoma on the second surveillance colonoscopy were age at index colonoscopy (scored 0 for younger than 55 years of age, 1 for 55-59 years of age, 2 for 60-64 years of age, and 3 for older than 65 years of age) and previous findings (non-neoplastic, nonadvanced, advanced [scored 0, 1, and 2, respectively]) on index colonoscopy and the first surveillance colonoscopy, with scores ranging from 1 to 7. Risks of advanced adenoma on the second surveillance colonoscopy with scores of 5 or less and more than 5 were 4.8% (95% confidence interval, 3.5%-6.4%) and 14.9% (95% confidence interval, 7.4%-25.7%), respectively, comprising 93% and 7%, respectively, of the cohort. Corresponding results in the validation cohort were 5.6% and 19.2%, respectively, comprising 86.1% and 13.9%, respectively, of the cohort.

LIMITATIONS

Retrospective study with potential for selection bias.

CONCLUSION

This index stratifies the risk of advanced adenoma on the second surveillance colonoscopy. If validated independently, it may be useful for tailoring surveillance.

Emergency department utilization can indicate early diagnosis of digestive tract cancers: A population-based study in Taiwan

BACKGROUND AND OBJECTIVE

Patients who visit emergency department (ED) may have symptoms of occult cancers.

METHODS

We studied a random cohort of one million subjects from Taiwan National Health Insurance Research Database between 2000 and 2008 to evaluate the ED utilization of individuals who were subsequently diagnosed with digestive tract cancers. The case group was digestive tract cancer patients and the control group was traumatic fracture patients. We reviewed record of ED visits only from 4 to 15 months before the cancer diagnoses.

RESULTS

There were 2635 and 6665 in the case and control groups respectively. Patients' adjusted odds ratio with 95% confidence interval for the case group were 1.36 (1.06-1.74) for Abdominal ultrasound, 2.16 (1.61-2.90) pan-endoscopy, 1.72 (1.33-2.22) guaiac fecal-occult blood test, 1.42 (1.28-1.58) plain abdominal X-rays, 1.20 (1.09-1.32) SGOT, 1.27 (1.14-1.40) SGPT, 1.66 (1.41-1.95) total bilirubin, 2.41 (1.89-3.08) direct bilirubin, 1.21 (1.01-1.46) hemoglobin and 3.63 (2.66-4.94) blood transfusion, respectively. Blood transfusion in the ED was a significant predictor of the individual subsequently diagnosed with digestive tract cancer.

CONCLUSIONS

The health system could identify high risk patients early by real-time review of their ED utilization before the diagnosis of digestive tract cancers. We proposed a follow-up methodology for daily screening of patients with high risk of digestive tract cancer by informatics system in the ED.

Development of polyps and cancer in patients with a negative colonoscopy: a follow-up study of more than 20 years

Background. Adenomas are missed during colonoscopy. Aim. Assess the occurrence of colorectal cancer (CRC) and polyps in patients with a negative index colonoscopy (IC). Patients and Methods. All patients with a IC in 1992–1994, aged 40 and 60 years, were included. Exclusion criterion was presence of abnormalities, a family history, or surveillance. At the end of 2013 all records were studied in order to gather follow-up information. Results. 394 patients were included in four groups: group 1 patients who died, group 2 patients who were not in the hospital systems anymore, group 3 patients still visiting the hospital but not the department of gastroenterology, and group 4 patients undergoing new colonoscopies. In group 1, 2 patients died of CRC and 4 developed a polyp. No data were available from the patients in group 2. Patients in group 3 visited the outpatient clinics but did not undergo new colonoscopy. Patients in group 4 underwent additional colonoscopies. The yield was 35 patients polyps and three CRCs. Five patients (1.3%) developed CRC, and 39 (9%) developed a polyp. Conclusion. Given these results the number of potentially missed adenomas in IC is very low and the consequences of missed adenomas are highly exaggerated.