True versus Apparent Malaria Infection Prevalence: The Contribution of a Bayesian Approach

AIMS: To present a new approach for estimating the "true prevalence" of malaria and apply it to datasets from Peru, Vietnam, and Cambodia. METHODS: Bayesian models were developed for estimating both the malaria prevalence using different diagnostic tests (microscopy, PCR & ELISA), without the need of a gold standard, and the tests' characteristics. Several sources of information, i.e. data, expert opinions and other sources of knowledge can be integrated into the model. This approach resulting in an optimal and harmonized estimate of malaria infection prevalence, with no conflict between the different sources of information, was tested on data from Peru, Vietnam and Cambodia. RESULTS: Malaria sero-prevalence was relatively low in all sites, with ELISA showing the highest estimates. The sensitivity of microscopy and ELISA were statistically lower in Vietnam than in the other sites. Similarly, the specificities of microscopy, ELISA and PCR were significantly lower in Vietnam than in the other sites. In Vietnam and Peru, microscopy was closer to the "true" estimate than the other 2 tests while as expected ELISA, with its lower specificity, usually overestimated the prevalence. CONCLUSIONS: Bayesian methods are useful for analyzing prevalence results when no gold standard diagnostic test is available. Though some results are expected, e.g. PCR more sensitive than microscopy, a standardized and context-independent quantification of the diagnostic tests' characteristics (sensitivity and specificity) and the underlying malaria prevalence may be useful for comparing different sites. Indeed, the use of a single diagnostic technique could strongly bias the prevalence estimation. This limitation can be circumvented by using a Bayesian framework taking into account the imperfect characteristics of the currently available diagnostic tests. As discussed in the paper, this approach may further support global malaria burden estimation initiatives

RENAL SAFETY EVALUATION AFTER DOTAREM-ENHANCED-MRI COMPARED WITH NON-ENHANCED-MRI IN PATIENTS AT HIGH RISK OFDEVELOPING CONTRAST MEDIUM INDUCED NEPHROPATHY

In patients at high risk of developing contrast medium nephropathy is evaluate renal safety after MRI-enhanced with Dotarem, compared with patients submit non enhanced MR

Renal safety evaluation after Dotarem®-enhanced-MRI compared with non-enhanced-MRI in patients at high risk of developing contrast medium induced nephropathy

With the common use of contrast media (CM) in diagnostic and interventional procedures, contrast-induced nephropathy (CIN) has become one of the leading cause of hospital acquired acute renal injury. Although CIN has been well studied for iodinated CM, it remains under-investigated for gadolinium-based contrast agents (GBCAs). GBCAs are generally regarded as non-nephrotoxic, but their safety in high-risk patient populations still remains controversial. As of today, there is a lack of prospective studies including control group (i.e. patients not receiving CM) evaluating the influence of GBCAs on CIN incidence. Moreover, mechanisms involved in adverse drug reactions (ADRs) to contrast agents, their characteristics, frequency and risk factors are still a matter of debate. Nevertheless, it has been observed that GBCAs may be responsible for Nephrogenic Systemic Fibrosis (NSF), especially in severe renal impaired patients. The purpose of the study is to prospectively compare the renal safety of meglumine gadoterate (Dotarem®)-enhanced MRI to a control group (unenhanced-MRI) in at-risk patients (with at least moderate renal insufficiency)