Background: The aim of this study is to assess the prevalence of abnormal urine analysis and kidney dysfunction in COVID-19 patients and to determine the association of acute kidney injury (AKI) with the severity and prognosis of COVID-19 patients. Methods: The electronic database of Embase and PubMed were searched for relevant studies. A meta-analysis of eligible studies that reported the prevalence of abnormal urine analysis and kidney dysfunction in COVID-19 was performed. The incidences of AKI were compared between severe versus non-severe patients and survivors versus non-survivors. Results: A total of 24 studies involving 4963 confirmed COVID-19 patients were included. The proportions of patients with elevation of sCr and BUN levels were 9.6% (95% CI 5.7–13.5%) and 13.7% (95% CI 5.5–21.9%), respectively. Of all patients, 57.2% (95% CI 40.6–73.8%) had proteinuria, 38.8% (95% CI 26.3–51.3%) had proteinuria +, and 10.6% (95% CI 7.9–13.3%) had proteinuria ++ or +++. The overall incidence of AKI in all COVID-19 patients was 4.5% (95% CI 3.0–6.0%), while the incidence of AKI was 1.3% (95% CI 0.2–2.4%), 2.8% (95% CI 1.4–4.2%), and 36.4% (95% CI 14.6–58.3%) in mild or moderate cases, severe cases, and critical cases, respectively. Meanwhile, the incidence of AKI was 52.9%(95% CI 34.5–71.4%), 0.7% (95% CI − 0.3–1.8%) in non-survivors and survivors, respectively. Continuous renal replacement therapy (CRRT) was required in 5.6% (95% CI 2.6–8.6%) severe patients, 0.1% (95% CI − 0.1–0.2%) non-severe patients and 15.6% (95% CI 10.8–20.5%) non-survivors and 0.4% (95% CI − 0.2–1.0%) survivors, respectively. Conclusion: The incidence of abnormal urine analysis and kidney dysfunction in COVID-19 was high and AKI is closely associated with the severity and prognosis of COVID-19 patients. Therefore, it is important to increase awareness of kidney dysfunction in COVID-19 patients.

The relationship between albumin corrected anion gap (ACAG) and mortality in acute kidney injury (AKI) patients who received continuous renal replacement therapy (CRRT) has not been investigated in any previous studies. This study aimed to investigate the relationship between ACAG at CRRT initiation and all-cause mortality among these patients in the intensive care unit (ICU). Patients diagnosed with AKI and treated with CRRT in the ICU from the Medical Information Mart for Intensive Care-IV version 1.0 (MIMIC IV) database and Huzhou Central Hospital were retrospectively enrolled. Participants were divided into two groups: the normal ACAG group (12–20 mmol/L) and high ACAG group (> 20 mmol/L). The Kaplan–Meier method and log-rank test were used to compare the survival rate between the two groups. Restricted cubic spine (RCS) and Cox proportional-hazards models were utilized to analyze the relationship between ACAG at CRRT initiation and ICU all-cause mortality of these patients. A total of 708 patients met the inclusion criteria in the study. The all-cause mortality of these patients during ICU hospitalization was 41.95%. Patients in the high ACAG group exhibited significantly higher ICU all-cause mortality rate than patients in the normal ACAG group (all P < 0.001). The Kaplan–Meier survival curves showed that the normal ACAG group had a higher ICU cumulative survival rate than the high ACAG group (log-rank test, χ₁²= 13.620, χ₂² = 12.460, both P < 0.001). In the multivariate COX regression analyses, patients with higher ACAG (> 20 mmol/L) levels at the time of CRRT initiation in the MIMIC IV database and Huzhou Central Hospital were significantly correlated with ICU all-cause mortality after adjusting multiple potential confounding factors with hazard ratios of 2.852 (95% CI 1.718–4.734) and 2.637(95% CI 1.584–4.389), respectively. In critically AKI patients who undergo CRRT, higher ACAG (> 20 mmol/L) level at the initiation of CRRT was significantly correlated with ICU all-cause mortality. Therefore, clinicians should pay more attention to those patients with a higher ACAG value.

Background The aim of this meta-analysis is to assess the prevalence of coagulation dysfunction in Chinese COVID-19 patients and to determine the association of coagulopathy with the severity and prognosis of COVID-19. Methods A meta-analysis of the prevalence of different abnormal coagulation indicators in COVID-19 patients in China was performed. The difference of coagulation indicators and the incidence of DIC were compared between severe cases and nonsevere cases as well as nonsurvivors and survivors, respectively. Results A total of 22 Chinese studies involving 4,889 confirmed COVID-19 inpatients were included. The average D-dimer value of COVID-19 patients is 0.67 µg/mL (95% confidence interval [CI]: 0.56–0.78), and 29.3% (95% CI: 20.1–38.5%) of patients showed elevated D-dimer values. Severe patients had significantly higher D-dimer levels and prolonged prothrombin time (PT) compared with nonsevere patients. Nonsurvivors had significantly higher D-dimer levels, prolonged PT, and decreased platelet count compared with survivors. In total, 6.2% (95% CI: 2.6–9.9%) COVID-19 patients were complicated by disseminated intravascular coagulation (DIC), in which the log risk ratio in nonsurvivors was 3.267 (95% CI: 2.191–4.342, Z = 5.95, p < 0.05) compared with that in survivors. Conclusion The prevalence of coagulopathy in Chinese COVID-19 inpatients is high, and both the abnormal coagulation indicators and DIC are closely associated with the severity and poor prognosis of these COVID-19 patients. Therefore, attention should be paid to coagulation dysfunction in COVID-19 patients. Closely monitoring of coagulation indicators and application of appropriate anticoagulation may improve the prognosis of COVID-19 inpatients in China. All the authors have participated in literature retrieval and viewpoint discussion in this article. S.J. and Y.J. contributed in writing this article. Y.J. did the statistics. X.Y. revised the article. All authors read and approved the final manuscript. The study does not require ethical approval because the meta-analysis is based on published research and the original data are anonymous. ^* These authors contributed equally to this article.

Non-invasive imaging in the near-infrared region (NIR) offers enhanced tissue penetration, reduced spontaneous fluorescence of biological tissues, and improved signal-to-noise ratio (SNR), rendering it more suitable for in vivo deep tissue imaging. In recent years, a plethora of NIR photoresponsive materials have been employed for disease diagnosis, particularly acute kidney injury (AKI). These encompass inorganic nonmetallic materials such as carbon (C), silicon (Si), phosphorus (P), and upconversion nanoparticles (UCNPs); precious metal nanoparticles like gold and silver; as well as small molecule and organic semiconductor polymer nanoparticles with near infrared responsiveness. These materials enable effective therapy triggered by NIR light and serve as valuable tools for monitoring AKI in living systems. The review provides a concise overview of the current state and pathological characteristics of AKI, followed by an exploration of the application of nanomaterials and photoresponsive nanomaterials in AKI. Finally, it presents the design challenges and prospects associated with NIR photoresponsive materials in AKI.