Although randomised controlled trials are considered the gold standard in clinical research, they are not always feasible due to limitations in the study population, challenges in obtaining evidence, high costs and ethical considerations. As a result, single-arm trial designs have emerged as one of the methods to address these issues. Single-arm trials are commonly applied to study advanced-stage cancer, rare diseases, emerging infectious diseases, new treatment methods and medical devices. Single-arm trials have certain ethical advantages over randomised controlled trials, such as providing equitable treatment, respecting patient preferences, addressing rare diseases and timely management of adverse events. While single-arm trials do not adhere to the principles of randomisation and blinding in terms of scientific rigour, they still incorporate principles of control, balance and replication, making the design scientifically reasonable. Compared with randomised controlled trials, single-arm trials require fewer sample sizes and have shorter trial durations, which can help save costs. Compared with cohort studies, single-arm trials involve intervention measures and reduce external interference, resulting in higher levels of evidence. However, single-arm trials also have limitations. Without a parallel control group, there may be biases in interpreting the results. In addition, single-arm trials cannot meet the requirements of randomisation and blinding, thereby limiting their evidence capacity compared with randomised controlled trials. Therefore, researchers consider using single-arm trials as a trial design method only when randomised controlled trials are not feasible.

Objectives: To evaluate (1) the relationship between heating, ventilation, and air conditioning (HVAC) systems and bioaerosol concentrations in hospital rooms, and (2) the effectiveness of laminar air flow (LAF) and high efficiency particulate air (HEPA) according to the indoor bioaerosol concentrations. Methods: Databases of Embase, PubMed, Cochrane Library, MEDLINE, and Web of Science were searched from 1st January 2000 to 31st December 2020. Two reviewers independently extracted data and assessed the quality of the studies. The samples obtained from different areas of hospitals were grouped and described statistically. Furthermore, the meta-analysis of LAF and HEPA were performed using random-effects models. The methodological quality of the studies included in the meta-analysis was assessed using the checklist recommended by the Agency for Healthcare Research and Quality. Results: The mean CFU/m³ of the conventional HVAC rooms and enhanced HVAC rooms was lower than that of rooms without HVAC systems. Furthermore, the use of the HEPA filter reduced bacteria by 113.13 (95% CI: -197.89, -28.38) CFU/m³ and fungi by 6.53 (95% CI: -10.50, -2.55) CFU/m³. Meanwhile, the indoor bacterial concentration of LAF systems decreased by 40.05 (95% CI: -55.52, -24.58) CFU/m³ compared to that of conventional HVAC systems. Conclusions: The HVAC systems in hospitals can effectively remove bioaerosols. Further, the use of HEPA filters is an effective option for areas that are under-ventilated and require additional protection. However, other components of the LAF system other than the HEPA filter are not conducive to removing airborne bacteria and fungi. Limitation of study: Although our study analysed the overall trend of indoor bioaerosols, the conclusions cannot be extrapolated to rare, hard-to-culture, and highly pathogenic species, as well as species complexes. These species require specific culture conditions or different sampling requirements. Investigating the effects of HVAC systems on these species via conventional culture counting methods is challenging and further analysis that includes combining molecular identification methods is necessary. Strength of the study: Our study was the first meta-analysis to evaluate the effect of HVAC systems on indoor bioaerosols through microbial incubation count. Our study demonstrated that HVAC systems could effectively reduce overall bioaerosol concentrations to maintain better indoor air quality. Moreover, our study provided further evidence that other components of the LAF system other than the HEPA filter are not conducive to removing airborne bacteria and fungi. Practical implication: Our research showed that HEPA filters are more effective at removing bioaerosols in HVAC systems than the current LAF system. Therefore, instead of opting for the more costly LAF system, a filter with a higher filtration rate would be a better choice for indoor environments that require higher air quality; this is valuable for operating room construction and maintenance budget allocation.

Background: The global burden of diet-related chronic diseases and their future projections remain unclear. To address this gap, we present the latest data on deaths and disability-adjusted life years attributable to dietary factors from 1990 to 2021, focusing on noncommunicable diseases worldwide. Additionally, we provide predictions of mortality rates across different age groups through 2030.Methods: Data from the Global Burden of Disease Study 2021 were analyzed to evaluate correlations between dietary factors and trends in chronic disease burden over a 30-year period. Moreover, we predicted the burden of chronic dietary diseases up to 2030.Results: From 1990 to 2021, global age-standardized mortality rates and disability-adjusted life year (DALY) rates associated with dietary factors decreased by approximately one-third for neoplasms and cardiovascular diseases (CVDs). In high sociodemographic index (SDI) regions, neoplasm-related deaths showed a stronger correlation with dietary factors, particularly high red meat intake. In cardiovascular diseases, the leading dietary factors are low-grain diets, whereas in diabetes, it is due to increased intake of processed meat. In low-SDI regions, diets low in vegetables showed the strongest association with neoplasm-related mortality, while diets low in fruits were significantly linked to CVD and diabetes burden. High-sodium diet was a significant risk factor for CVD in the middle-SDI regions. Moreover, the 2030 projections indicated a decline in mortality from neoplasms and CVDs, with a slight increase in mortality rates from diabetes.Conclusion: The global burden of chronic diseases linked to dietary factors shows varying trends across different countries and regions, particularly influenced by their economic development levels. This variation underscores the necessity of enhancing dietary structures to mitigate chronic disease prevalence and foster overall health.

Background. Hematopoietic stem cell transplantation (HSCT) has become the main treatment for acute myeloid leukemia (AML) and has been studied in many systematic reviews (SRs), but strong conclusions have not been drawn yet. Objective. This study aimed to summarize and critically evaluate the methodological and evidence quality of SRs and meta‐analysis on this topic. Methods. PubMed, Embase, the Cochrane Library, and Web of Science were searched for SRs/meta‐analyses regarding HSCT for AML. Two reviewers assessed the quality of SRs/meta‐analyses in line with AMSTAR‐2 and evaluated the strength of evidence quality with the grading of the evaluation system (GRADE) for concerned outcomes independently. Results. 12 SR/Meta articles were included, and the AMSTAR‐2 scale showed that the quality grade of all articles was low or very low. GRADE results showed 29 outcomes, 2 of which were high, 12 were moderate, and 15 were low. Limitations and inconsistency were the most important factors leading to degradation, followed by imprecision and publication bias. Allo‐SCT had better OS and DFS benefits than auto‐SCT and significantly reduced the relapse in intermediate‐risk AML/CR1 patients. Auto‐SCT was associated with lower TRM than allo‐SCT but generally had higher relapse. The results should be confirmed further for the low or moderate evidence quality. Conclusion. Current SRs show that allo‐SCT in the treatment of AML might improve the OS, RFS, and DFS. Auto‐SCT has significantly lower TRM but higher RR. Whether bone marrow transplantation is superior to nonmyeloablative chemotherapy remains to be evaluated. Meanwhile, the quality of methodology needs to be further improved. The intensity of evidence was uneven, and the high‐quality evidence of outcomes was lacking. Considering the limitations of our overview, more rigorous and scientific studies are needed to fully explore the efficacy of different interventions of HSCT in AML, and clinicians should be more cautious in the treatment.

Published studies have reported conflicting and heterogeneous results regarding the association between human leukocyte antigen (HLA)-DRB1 polymorphisms and alopecia areata (AA). This study aimed to review and quantitatively analyze the association between HLA-DRB1 polymorphisms and AA. In this study, all relevant publications were searched through December 2016. Odds ratios (ORs) and confidence intervals (CIs) for comparisons between case and control groups were calculated. Stata 14.0 software was used to perform statistical analysis. This research does not require formal ethical approval because the data used in this analysis do not involve personal information and thus do not affect privacy. Twelve articles were identified. For HLA-DRB1*04 and HLA-DRB1*16 polymorphisms, the OR (95% CIs) was 1.49 (1.24–1.78) and 1.61 (1.08–2.41), and P was <.01 and <.01, respectively. For HLA-DRB1*0301, HLA-DRB1*09, and HLA-DRB1*13 polymorphisms, the OR (95% CIs) was 0.42 (0.28–0.63), 0.74 (0.55–0.99), and 0.62 (0.40–0.98), and P was <.01, <.01, and <.01, respectively. Statistical evidence revealed no publication bias (P > .05). The present meta-analysis suggested that HLA-DRB1*04 and HLA-DRB1*16 polymorphisms might be associated with increased AA risk, while HLA-DRB1*0301, HLA-DRB1*09, and HLA-DRB1*13 polymorphisms might decrease the AA risk. Studies with adequate methodological quality on gene–gene and gene–environment interactions are needed to validate the results in the future.