Amino acid formula as a new strategy for diagnosing cow's milk allergy in infants: is it cost-effective?

AIMS

To estimate the cost-effectiveness of a new strategy that uses an amino acid formula in the elimination diet of infants with suspected cow's milk allergy (CMA).

MATERIALS AND METHODS

This pharmacoeconomic study was developed from the perspective of the Brazilian Public Healthcare System. The new strategy proposes using an amino acid formula in the diagnostic elimination diet of infants (≤24 months) with suspected CMA. The rationale is that infants who do not respond to the amino acid formula do not suffer from CMA. Patients with a positive oral challenge test receive a therapeutic elimination diet based on Brazilian Food Allergy Guidelines. This approach was compared to the current recommendations of the Brazilian Food Allergy Guidelines. A decision model was constructed using TreeAge Pro 2012 software. Model inputs were based on a literature review and the opinions of a panel of experts. A univariate sensitivity analysis of incremental cost-effectiveness ratios was performed.

RESULTS

The mean cost per patient of the new amino acid formula strategy was R$3,341.57, while the cost of the current Brazilian guidelines strategy was R$3,641.08. The mean number of symptom-free days per patient, which was used as an indicator of effectiveness, was 900.6 and 875.7 days, respectively. The new strategy is, therefore, dominant. In the sensitivity analysis, the dominance was maintained with parameter variation.

LIMITATIONS

In the absence of information in the literature, some premises were defined by a panel of specialists.

CONCLUSIONS

The new strategy, which uses an amino acid formula in the elimination diagnostic diet followed by an oral food challenge, is a dominant pharmacoeconomic approach that has a lower cost and results in an increased number of symptom-free days.

[On the question of the development of medical-economic standard of diagnostics of oncologic diseases of the upper gastrointestinal tract in outpatient clinics of Saint Petersburg]

The authors investigated general principles and specific development of medico-economic standard-based data-processing system, "Expert-MES", for early diagnosis of tumors of the upper gastrointestinal tract. The method of calculating the actual cost of diagnostic measures is demonstrated with regard to necessary volumes. The possibilities of monitoring the implementation of MES in request of patients for examination in outpatient clinics are evaluated.

Implementation of colon cancer screening: techniques, costs, and barriers

Colorectal cancer and breast cancer are the only cancer sites for which evidence on the efficacy of screening is available from randomized trials. The trials on colon cancer screening in the United States and Europe used the fecal occult blood test as the primary screen, but randomized trial data are not yet available on endoscopy (flexible sigmoidoscopy to 60 cm), and no randomized, controlled trials of colonoscopy as a screening test are in progress. This article reviews colorectal cancer screening from an epidemiologist's perspective to provide the theoretic evidence-based underpinning for the role of the gastroenterologist in colorectal screening.

Which test is best for Helicobacter pylori? A cost-effectiveness model using decision analysis

GPs face a potential dilemma in deciding which test to use for detection of Helicobacter pylori. For patients with dyspepsia, the National Institute for Health and Clinical Excellence (NICE) advises primary care practitioners to adopt a 'test and treat' policy before considering a referral for gastroscopy. There are many ways of testing: serology, urea breath test, and faecal antigen test. NICE does not advocate any preferred single test for detecting H. pylori. In the current study a multi-stakeholder 2-day workshop was established to agree and populate a cost-effectiveness decision analysis model. The aim was to analyse the three types of tests available for H. pylori and to determine which is the most practical and cost effective. Agreement on the costs and diagnostic values to be entered into the decision-analytic model was achieved. Results indicate that the faecal antigen test was the most effective in terms of true outcomes and cost. One thousand virtual patients were allocated to each of the three tests. Serology had 903, urea breath test had 961, and the faecal antigen test had 968 true positive outcomes. Data indicate that the faecal antigen test is the preferable strategy for diagnosis of H. pylori in primary care. This has implications for implementing new testing processes and for commissioning new diagnostic pathways for use in primary care.

Transient elastography (FibroScan) for non-invasive assessment of liver fibrosis

(1) Liver fibrosis is associated with significant morbidity and mortality. The major cause is hepatitis C, which affects 240,000 Canadians. (2) Assessing the degree of liver fibrosis is critical to its management. Liver biopsy, an invasive procedure, is considered to be the diagnostic gold standard. (3) FibroScan is a rapid, non-invasive technology that uses low frequency vibration and ultrasound to assess the stiffness of liver tissue. (4) The diagnostic performance of FibroScan is good for identifying severe fibrosis or cirrhosis, but it is less accurate for milder presentations. (5) FibroScan is a promising technology, but large multi-centre trials comparing a range of emerging non-invasive fibrosis staging technologies are required.

Clinical application of polymerase chain reaction to diagnose Clostridium difficile in hospitalized patients with diarrhea

BACKGROUND & AIMS

Clostridium difficile is a common cause of diarrhea in hospitalized patients and is associated with significant morbidity and cost. The current diagnostic standard, enzyme immunoassay (EIA), has low sensitivity, leading to duplicate testing and empiric treatment. We sought to show the usefulness and potential cost effectiveness of polymerase chain reaction (PCR) amplification of toxin B gene for diagnosis of C. difficile-induced diarrhea.

METHODS

A total of 148 stool samples from academic and community-based hospitals were sent for EIA testing and were evaluated prospectively for the presence of toxin B gene by PCR. Results were compared with EIA regarding sensitivity, specificity, and predictive values. Medical charts were reviewed to determine the following: (1) number of EIAs sent per admission, (2) number sent within a 24-hour time period, and (3) how caregivers practiced based on EIA results.

RESULTS

The mean age of 130 patients was 55 years. EIA and PCR were positive in 6.8% and 13.6% of patients, respectively. EIA sensitivity was 40%, specificity was 98%, and positive and negative predictive values were 80% and 91%, respectively. The cost of the PCR was $22/sample. Empiric treatment for C. difficile was given unnecessarily in 42% of EIA-negative results. Thirty percent of patients had 3 or more EIAs sent during their hospital admission. Of patients with multiple samples sent, 57% had more than 1 sample sent in a 24-hour period.

CONCLUSIONS

Many physicians do not conform to practice guidelines regarding recommended diagnosis and empiric treatment of C. difficile. Toxin B gene PCR represents a more sensitive and potentially cost-effective method to diagnose C. difficile-induced diarrhea than EIA and should be considered for use as an alternative diagnostic standard.

Estimating medical costs of gastroenterological diseases

AIM: To estimate the direct medical costs of gastroenterological diseases within the universal health insurance program among the population of local residents in Taiwan.

METHODS: The data sources were the first 4 cohort datasets of 200 000 people from the National Health Insurance Research Database in Taipei. The ambulatory, inpatient and pharmacy claims of the cohort in 2001 were analyzed. Besides prevalence and medical costs of diseases, both amount and costs of utilization in procedures and drugs were calculated.

RESULTS: Of the cohort with 183 976 eligible people, 44.2% had ever a gastroenterological diagnosis during the year. The age group 20-39 years had the lowest prevalence rate (39.2%) while the elderly had the highest (58.4%). The prevalence rate was higher in women than in men (48.5% vs. 40.0%). Totally, 30.4% of 14 888 inpatients had ever a gastroenterological diagnosis at discharge and 18.8% of 51 359 patients at clinics of traditional Chinese medicine had such a diagnosis there. If only the principal diagnosis on each claim was considered, 16.2% of admissions, 8.0% of outpatient visits, and 10.1% of the total medical costs (8 469 909 US dollars/ 83 830 239 US dollars) were attributed to gastroenterological diseases. On average, 46.0 US dollars per insured person in a year were spent in treating gastroenterological diseases. Diagnostic procedures related to gastroenterological diseases accounted for 24.2% of the costs for all diagnostic procedures and 2.3% of the total medical costs. Therapeutic procedures related to gastroenterological diseases accounted for 4.5% of the costs for all therapeutic procedures and 1.3% of the total medical costs. Drugs related to gastroenterological diseases accounted for 7.3% of the costs for all drugs and 1.9% of the total medical costs.

CONCLUSION: Gastroenterological diseases are prevalent among the population of local residents in Taiwan, accounting for a tenth of the total medical costs. Further investigations are needed to differentiate costs in screening, ruling out, confirming, and treating.

Motility and GI function studies billing and coding guidelines: a position paper of the American Motility Society

Tests that measure gastrointestinal function, such as esophageal motility testing, ambulatory twenty-four hour pH, electrogastrography, gastroduodenal, sphincter of Oddi, and anorectal manometry, as well as hydrogen breath testing are now an essential part in the evaluation of patients with functional gastrointestinal disorders. They are widely performed in a variety of clinical settings. In this paper we outline the position of the American Motility Society on billing and coding for these studies, and review the issues for these studies under the current United States Relative Value Scale system. We have also provided an outline for standardization of reports for these procedures, and propose changes and modifications of current medical necessity diagnoses.

The end of diagnosis: when to stop testing

Defining the end of diagnosis and deciding when to stop further testing represent crucial features of many medical pursuits. The aim of this article is to analyze the principles that govern the decision to discontinue a chain of consecutive diagnostic tests. Using Bayes formula and threshold analysis, four common "stop rules" of medical diagnostics can be derived. The first rule relates to a lack of therapeutic consequence associated with continued testing. The second rule concerns empirical therapy, that is, the use of a benign, effective, and specific type of therapy to cap a diagnostic chain and use therapeutic success as confirmation for a diagnostic suspicion. The third rule states that the benefit of a suspected diagnosis should stay higher than the costs of a test invested in confirming its presence. Lastly, as the fourth rule, the cumulative test costs should not exceed the expected risks of a missed diagnosis. Although in clinical practice the ambiguities and variations among patients may compromise the calculation of exact stop values for each rule, knowledge of these underlying general principles may be sufficiently helpful in managing the individual patient.

A new optics-based gastroesophageal reflux probe

This work was carried out with the purpose of developing a new method of gastroesophageal reflux (GOR) detection. It is based on the emission of a light beam to the inferior part of the oesophagus and on the detection and analysis of the corresponding reflected light intensity. The optical properties of the oesophageal lumen are then used to identify the GOR episodes, solving, in this way, the existing drawback of using pH probes that fail in the cases where GOR episodes are neutral or short duration acid. The necessary instrumentation for the application of this new technique, including the probe itself and its associated optics, was developed. The result is a low-cost portable instrument, based on the Microchip microcontroller PIC16C77, with enough flexibility to be used in other biomedical applications. This new simple apparatus only needs an adequate light source - diode laser - and an adequate photosensor - photodiode - to make the interface to the probe that guides the light to and from oesophagus. Our results show the capability of this new technique to make the identification of GOR episodes.

Economic constraints in the diagnosis of peptic ulcer disease

BACKGROUND

The discovery of Helicobacter pylori and its role in upper gastrointestinal disease has changed the outlook on diagnosis of peptic ulcer disease.

OBJECTIVES

To address the questions of what types of diagnostic tests and how many of each type are needed to diagnose among patients with dyspepsia as many ulcers as possible at least cost.

METHODS

Bayes' formula and a decision tree were used to follow the outcomes of alternative test combinations for ulcer diagnosis.

RESULTS

Assuming unlimited resources, only endoscopy of all subjects results in the correct diagnoses of all ulcers, but costs $5600 per diagnosis. Barium swallow followed by endoscopy is less expensive ($2980), but misses 5% of all ulcers. Serology for H. pylori followed by endoscopy or barium meal provides relatively high diagnostic yields (85 or 81% of all ulcers detected) at lower costs ($2900 or $1050 per ulcer diagnosis, respectively). In general, a higher number of ulcers is found at a lower cost if the cheap tests are used to screen patients before subjecting them to the more expensive tests.

CONCLUSIONS

The ideal work-up depends on the urgency of a correct diagnosis, the willingness to miss some ulcer diagnoses and the availability of resources. H. pylori serology followed by endoscopy or barium meal represents two cost-effective strategies.