Research and statistics: likelihood ratio in diagnosis

Diagnostic value of biomarkers for paediatric urinary tract infections in primary care: systematic review and meta-analysis

Background

Accurate diagnosis of urinary tract infection is essential as children left untreated may suffer permanent renal injury.

Aim

To compare the diagnostic values of biomarkers or clinical prediction rules for urinary tract infections in children presenting to ambulatory care.

Design and setting

Systematic review and meta-analysis of ambulatory care studies.

Methods

Medline, Embase, WOS, CINAHL, Cochrane library, HTA and DARE were searched until 21 May 2021. We included diagnostic studies on urine or blood biomarkers for cystitis or pyelonephritis in children below 18 years of age. We calculated sensitivity, specificity and likelihood ratios. Data were pooled using a bivariate random effects model and a Hierarchical Summary Receiver Operating Characteristic analysis.

Results

Seventy-five moderate to high quality studies were included in this review and 54 articles in the meta-analyses. The area under the receiver-operating-characteristics curve to diagnose cystitis was 0.75 (95%CI 0.62 to 0.83, n = 9) for C-reactive protein, 0.71 (95% CI 0.62 to 0.80, n = 4) for procalcitonin, 0.93 (95% CI 0.91 to 0.96, n = 22) for the dipstick test (nitrite or leukocyte esterase ≥trace), 0.94 (95% CI 0.58 to 0.98, n = 9) for urine white blood cells and 0.98 (95% CI 0.92 to 0.99, n = 12) for Gram-stained bacteria. For pyelonephritis, C-reactive protein < 20 mg/l had LR- of 0.10 (95%CI 0.04–0.30) to 0.22 (95%CI 0.09–0.54) in children with signs suggestive of urinary tract infection.

Conclusions

Clinical prediction rules including the dipstick test biomarkers can support family physicians while awaiting urine culture results. CRP and PCT have low accuracy for cystitis, but might be useful for pyelonephritis.

Supplementary Information

The online version contains supplementary material available at 10.1186/s12875-021-01530-9.

Clinical Features for the Diagnosis of Pediatric Urinary Tract Infections: Systematic Review and Meta-Analysis

PURPOSE

Accurate diagnosis of urinary tract infection in children is essential because children left untreated can experience permanent renal injury. We aimed to assess the diagnostic value of clinical features of pediatric urinary tract infection.

METHODS

We performed a systematic review and meta-analysis of diagnostic test accuracy studies in ambulatory care. We searched the PubMed, Embase, Web of Science, Cumulative Index to Nursing and Allied Health Literature, Cochrane Central Register of Controlled Trials, Health Technology Assessment, and Database of Abstracts of Reviews of Effects databases from inception to January 27, 2020 for studies reporting 2 × 2 diagnostic accuracy data for clinical features compared with urine culture in children aged <18 years. For each clinical feature, we calculated likelihood ratios and posttest probabilities of urinary tract infection. To estimate summary parameters, we conducted a bivariate random effects meta-analysis and hierarchical summary receiver operating characteristic analysis.

RESULTS

A total of 35 studies (N = 78,427 patients) of moderate to high quality were included, providing information on 58 clinical features and 6 prediction rules. Only circumcision (negative likelihood ratio [LR-] 0.24; 95% CI, 0.08-0.72; n = 8), stridor (LR- 0.20; 95% CI, 0.05-0.81; n = 1), and diaper rash (LR- 0.13; 95% CI, 0.02-0.92; n = 1) were useful for ruling out urinary tract infection. Body temperature or fever duration showed limited diagnostic value (area under the receiver operating characteristic curve 0.61; 95% CI, 0.47-0.73; n = 16). The Diagnosis of Urinary Tract Infection in Young Children score, Gorelick Scale score, and UTIcalc (https://uticalc.pitt.edu) might be useful to identify children eligible for urine sampling.

CONCLUSIONS

Few clinical signs and symptoms are useful for diagnosing or ruling out urinary tract infection in children. Clinical prediction rules might be more accurate; however, they should be validated externally. Physicians should not restrict urine sampling to children with unexplained fever or other features suggestive of urinary tract infection.

Diagnostic accuracy of adenosine deaminase for tuberculous peritonitis: a meta-analysis

INTRODUCTION

Tuberculous peritonitis remains a diagnostic challenge for clinicians. Many studies have investigated the usefulness of adenosine deaminase (ADA) in ascites for the diagnosis of tuberculous peritonitis; however, the overall diagnostic accuracy of ADA for tuberculous peritonitis remains unclear. The aim of the present meta-analysis was to determine the overall accuracy of ADA measurements in the diagnosis of tuberculous peritonitis.

MATERIAL AND METHODS

We performed a systematic search in PubMed and Embase to identify published studies that evaluated the diagnostic role of ADA for tuberculous peritonitis. Quality was assessed according to standardized Quality Assessment of Diagnostic Accuracy Studies criteria. Sensitivity, specificity and other measures of accuracy of ADA assay in order to diagnose tuberculous peritonitis were pooled using random effects models. Summary receiver operating characteristic curve (SROC) was used to summarize overall test performance.

RESULTS

Sixteen studies met inclusion criteria for the present meta-analysis. The pooled sensitivity and specificity for diagnosing tuberculous peritonitis were 0.93 (95% CI: 0.89-0.95) and 0.96 (95% CI: 0.94-0.97), respectively. The positive likelihood ratio was 15.80 (95% CI: 10.87-22.95), negative likelihood ratio was 0.09 (95% CI: 0.05-0.16) and diagnostic odds ratio was 249.28 (95% CI: 113.11-549.39). The area under the SROC was 0.98.

CONCLUSIONS

Ascitic ADA determination is a relatively sensitive and specific test for the diagnosis of tuberculous peritonitis. Measurement of ADA in ascites is thus likely to be a useful diagnostic method for tuberculous peritonitis.

Efficacy of Canadian computed tomography head rule in predicting the need for a computed-axial tomography scans among patients with suspected head injuries

Context:

The use of imaging modalities is crucial in the diagnostic field of critical medicine. However, the ethical and economic use of these techniques has become a major concern especially in resource-poor settings. The Canadian computed tomography Head Rule (CCHR) is being increasingly used all over the world to evaluate the necessity of a Computer-assisted Tomography (CT) scan in patients with suspected head injury.

Aim:

The aim of the current study is to evaluate the efficacy of CCHR to predict the occurrence of head injury, as evidenced radiologically by a CT Head, at a government tertiary care clinical setting in south India.

Setting and Design:

The design was that of a hospital-based cross-sectional survey conducted at the Medical College Hospital, Thiruvananthapuram (Kerala, India).

Materials and Methods:

The study subjects were patients with suspected head injury evaluated at the Surgical Casualty Department of the study setting. Fifty consecutive patients with suspected head injury were enrolled in the study.

Statistical Analysis:

The Chi-square test was used to assess the statistical significance of association between the outcome variable and the exposure characteristics. The diagnostic ability of the Glasgow Coma Scale (GCS) and CCHR were expressed in terms of sensitivity and specificity by considering CT diagnosed Head injury as the gold standard diagnostic tool.

Results:

Clinical manifestations as measured by a GCS score < 13 failed to significantly predict a head injury in the CT scan. However, the same became statistically significant when the CCHR was added to the GCS score as a predictor (P value < 0.001). The sensitivity of the tool in predicting a head injury rose from 23.3 to 96.7%.

Conclusion:

The current study suggested that the CCHR could act as an excellent decision rule to indicate the need of a CT scan. The need of a decision rule was warranted in the context of the growth of newer diagnostic imaging facilities in India.