Systematic reviews of the effects of healthcare interventions are now quite common. There are currently more than 2 600 full Cochrane reviews in The Cochrane Library, with protocols published for 1 600 more. There are also thousands of systematic reviews published in other journals. However, the science of systematic reviewing is still relatively young. Most of the reviews available today rely on randomised trials, but there are also some reviews of non-randomised trials and of diagnostic test accuracy and these may become more common in the next few years. In this essay, I discuss some of the challenges of doing these newer types of systematic review, and show how experience gained in the last few decades of systematic reviews of randomised trials might help to meet these challenges.
Objective To evaluate the diagnosis value of purified protein derivative (PPD) antibody tests in childhood tuberculosis. Methods We reviewed 126 cases of hospitalization children tested body fluid PPD antibody by Enzyme-Linked Immunosorbent Assay (ELISA). Twenty-two them were diagnosed with tuberculosis. We determined the sensitivity, specificity, diagnostic likelihood ratio, positive prognostic value, negative prognostic value, post-test probability, respectively. Results The following accuracy statistics for the PPD body liquid antibody tests in this study: sensitivity, 45.45%; specificity, 91.35%; diagnostic likelihood ratio positive, 5.25; diagnostic likelihood ratio negative, 0.597; positive predictive value, 52.63%; negative predictive value, 88.79% and post-test probability, 48.09% in 15% of prevalence. Conclusion This study shows that body fluid PPD tests have limited value for diagnosis of tuberculosis in pediatric tuberculosis. Clinic physicians should be wary of the positive results of body fluid PPD antibody tests. The value of diagnosis is related to prevalence of tuberculosis in the specific hospital.
ObjectiveTo evaluate the diagnostic accuracy and efficacy of X-ray for evaluating the tip position of umbilical venous catheterization (UVC). MethodsThe PubMed, Embase, Cochrane Library, CBM, CNKI, VIP and WanFang Data databases were electronically searched to collect diagnostic tests for UVC tip localisation from inception to 1 May 2023. Two reviewers independently screened the literature according to the inclusion and exclusion criteria, extracted the data and assessed the quality of the studies using the QUADAS-2 tool. Then, meta-analysis was performed by using Stata 16.0 software. Results Twelve articles involving 1 055 patients were included. The sensitivity and specificity of Negar Yazdani’s study were both 100%. The results of the meta-analysis (the remaining eleven articles, n=951) indicated a pooled sensitivity of 0.7 (95%CI 0.6 to 0.8), a pooled specificity of 0.8 (95%CI 0.7 to 0.9), a positive likelihood ratio of 4.0 (95%CI 2.0 to 8.1), a negative likelihood ratio of 0.4 (95%CI 0.2 to 0.6) and a diagnostic odds ratio of 11 (95%CI 3 to 36) with an area under the cumulative receiver operating characteristic curve of 0.8 (95%CI 0.8 to 0.9). A subgroup analysis was performed according to the different methods of judging X, the 8th–9th thoracic, the 9th–10th thoracic and combined judgement of the diaphragmatic plane + the vertebral body + the heart shadow. The sensitivities of the 3 groups were 0.8 (95%CI 0.5 to 0.9), 0.5 (95%CI 0.4 to 0.7) and 0.8 (95%CI 0.6 to 0.9); the specificities of the 3 groups were 0.8 (95%CI 0.6 to 0.9), 0.76 (95%CI 0.6 to 0.9) and 0.91 (95%CI 0.79 to 0.96). The areas under the cumulative receiver operating characteristic curve were 0.9 (95%CI 0.8 to 0.9), 0.7 (95%CI 0.6 to 0.7) and 0.92 (95%CI 0.89 to 0.94). ConclusionSome error is present when determining the catheter tip position by X-ray, in which the evaluation of the umbilical vein catheter tip position through a comprehensive evaluation of the diaphragmatic plane, the heart margin and the vertebral body is more powerful than the evaluation of the vertebral body alone.