Comparison of validity of assessment methods using indices of adjusted agreement

Field Evaluation of the Performance of Two Rapid Diagnostic Tests for Meningitis in Niger and Burkina Faso

New lateral flow tests for the diagnosis of Neisseria meningitidis (Nm) (serogroups A, C, W, X, and Y), MeningoSpeed, and Streptococcus pneumoniae (Sp), PneumoSpeed, developed to support rapid outbreak detection in Africa, have shown good performance under laboratory conditions. We conducted an independent evaluation of both tests under field conditions in Burkina Faso and Niger, in 2018–2019. The tests were performed in the cerebrospinal fluid of suspected meningitis cases from health centers in alert districts and compared to reverse transcription polymerase chain reaction tests performed at national reference laboratories (NRLs). Health staff were interviewed about feasibility. A total of 327 cases were tested at the NRLs, with 26% confirmed Nm (NmC 63% and NmX 37%) and 8% Sp. Sensitivity and specificity were, respectively, 95% (95% CI: 89–99) and 90% (95% CI: 86–94) for Nm and 92% (95% CI: 75–99) and 99% (95% CI: 97–100) for Sp. Positive and negative predictive values were, respectively, 77% (95% CI: 68–85) and 98% (95% CI: 95–100) for Nm and 86% (95% CI: 67–96) and 99% (95% CI: 98–100) for Sp. Concordance showed 82% agreement for Nm and 97% for Sp. Interviewed staff evaluated the tests as easy to use and to interpret and were confident in their readings. Results suggest overall good performance of both tests and potential usefulness in meningitis outbreak detection.

Assessment of Nonradioactive Multispectral Optoacoustic Tomographic Imaging With Conventional Lymphoscintigraphic Imaging for Sentinel Lymph Node Biopsy in Melanoma

Importance

The metastatic status of sentinel lymph nodes (SLNs) is the most relevant prognostic factor in breast cancer, melanoma, and other tumors. The conventional standard to label SLNs is lymphoscintigraphy with technetium Tc 99m. A worldwide shortage and known disadvantages of Tc 99m have intensified efforts to establish alternative, nonradioactive imaging techniques.

Objective

To assess a new nonradioactive method using multispectral optoacoustic tomographic (MSOT) imaging in comparison with conventional lymphoscintigraphic imaging for SLN biopsy (SLNB) in melanoma.

Design, Setting, and Participants

Analysis of a cross-sectional study was conducted at the University Hospital-Essen, Skin Cancer Center, Essen, Germany. Between June 2, 2014, and February 22, 2019, 83 patients underwent SLNB with an additional preoperative indocyanine green (ICG) application. Sentinel lymph node basins were preoperatively identified by MSOT imaging, and ICG-labeled SLNs were intraoperatively detected using a near-infrared camera. The surgeons were blinded to the lymphoscintigraphic imaging results in the beginning of the SLNB. Use of a γ probe was restricted until the SLNB procedure was attempted by the nonradioactive method.

Main Outcomes and Measures

Concordance of SLN basins and SLNs identified by MSOT imaging plus near-infrared camera vs lymphoscintigraphic imaging plus single-photon emission computed tomographic or computed tomographic imaging was assessed.

Results

Of the 83 patients (mean [SD] age, 54.61 [17.53] years), 47 (56.6%) were men. In 83 surgical procedures, 165 SLNs were excised. The concordance rate of ICG-labeled and Tc 99m-marked detected SLN basins was 94.6% (n = 106 of 112). Intraoperatively, 159 SLNs were detected using a near-infrared camera and 165 were detected by a γ probe, resulting in a concordance rate of 96.4%. Multispectral optoacoustic tomographic imaging visualized SLNs in all anatomic regions with high penetration depth (5 cm).

Conclusions and Relevance

The findings of this study suggest that nonradioactive SLN detection via MSOT imaging allows identification of SLNs at a frequency equivalent to that of the current radiotracer conventional standard. Multispectral optoacoustic tomographic imaging appears to be a viable nonradioactive alternative to detect SLNs in malignant tumors.

Development of an instrument to evaluate intrapartum care quality in Senegal: evaluation quality care

OBJECTIVE

To evaluate the reliability of direct observation for measuring intrapartum care and compare this method with clinical audits using objective criteria based on patients' medical charts.

DESIGN

Cross-sectional study, data collected by two independent evaluators.

SETTING

Hospital in Dakar, Senegal.

PARTICIPANTS

Thirty consecutive intrapartum care episodes provided by midwives and the corresponding medical charts. Outcome Measure The presence or absence of each of twelve criteria selected on the basis of national and international norms for monitoring of labour and delivery (six criteria) and the immediate postpartum period (six criteria).

RESULTS

For direct observation, the labour and delivery mean quality scores ranged from 5.34 to 5.77. In contrast, for the chart-based method, the scores ranged from 0.32 to 0.45. For postpartum care evaluated only with direct observation, the scores were also high (5.21-5.65). For direct observation, inter-evaluator agreement was high: kappa coefficients varied from 0.78 to 0.93 depending on the criterion (total score ICC = 0.74). For the chart-based method, inter-evaluator agreement was also high: 0.66 to 1 (total score ICC = 0.72). Comparison of the two methods showed strong differences by items and subscores.

CONCLUSION

Using direct observation, the quality of obstetric care was high for both the monitoring of labour and delivery and postpartum care. Both measurement instruments showed high reliability. The chart-based method underestimated the quality of care because of poor medical record documentation. Medical-record-based measurement may not be appropriate for the evaluation of the quality of obstetric care in Senegal and other low-income settings.

Analyzing methods for path mining with applications in metabolomics

Metabolomics is one of the key approaches of systems biology that consists of studying biochemical networks having a set of metabolites, enzymes, reactions and their interactions. As biological networks are very complex in nature, proper techniques and models need to be chosen for their better understanding and interpretation. One of the useful strategies in this regard is using path mining strategies and graph-theoretical approaches that help in building hypothetical models and perform quantitative analysis. Furthermore, they also contribute to analyzing topological parameters in metabolome networks. Path mining techniques can be based on grammars, keys, patterns and indexing. Moreover, they can also be used for modeling metabolome networks, finding structural similarities between metabolites, in-silico metabolic engineering, shortest path estimation and for various graph-based analysis. In this manuscript, we have highlighted some core and applied areas of path-mining for modeling and analysis of metabolic networks.