Observational studies - should we simply ignore them in assessing transfusion outcomes?

Mechanical versus manual cardiopulmonary resuscitation (CPR): an umbrella review of contemporary systematic reviews and more

BACKGROUND

High-quality cardiopulmonary resuscitation (CPR) can restore spontaneous circulation (ROSC) and neurological function and save lives. We conducted an umbrella review, including previously published systematic reviews (SRs), that compared mechanical and manual CPR; after that, we performed a new SR of the original studies that were not included after the last published SR to provide a panoramic view of the existing evidence on the effectiveness of CPR methods.

METHODS

PubMed, EMBASE, and Medline were searched, including English in-hospital (IHCA) and out-of-hospital cardiac arrest (OHCA) SRs, and comparing mechanical versus manual CPR. A Measurement Tool to Assess Systematic Reviews (AMSTAR-2) and GRADE were used to assess the quality of included SRs/studies. We included both IHCA and OHCA, which compared mechanical and manual CPR. We analyzed at least one of the outcomes of interest, including ROSC, survival to hospital admission, survival to hospital discharge, 30-day survival, and survival to hospital discharge with good neurological function. Furthermore, subgroup analyses were performed for age, gender, initial rhythm, arrest location, and type of CPR devices.

RESULTS

We identified 249 potentially relevant records, of which 238 were excluded. Eleven SRs were analyzed in the Umbrella review (January 2014-March 2022). Furthermore, for a new, additional SR, we identified eight eligible studies (not included in any prior SR) for an in-depth analysis between April 1, 2021, and February 15, 2024. The higher chances of using mechanical CPR for male patients were significantly observed in three studies. Two studies showed that younger patients received more mechanical treatment than older patients. However, studies did not comment on the outcomes based on the patient's gender or age. Most SRs and studies were of low to moderate quality. The pooled findings did not show the superiority of mechanical compared to manual CPR except in a few selected subgroups.

CONCLUSIONS

Given the significant heterogeneity and methodological limitations of the included studies and SRs, our findings do not provide definitive evidence to support the superiority of mechanical CPR over manual CPR. However, mechanical CPR can serve better where high-quality manual CPR cannot be performed in selected situations.

Transfusion strategy trials excluding patients transfused outside the trial study period are more likely to report a trend favoring restrictive strategies: a meta-analysis

OBJECTIVES

Some large, randomized trials investigating red cell transfusion strategies have significant numbers of transfusions administered outside the trial study period. We sought to investigate the potential impact of this methodological issue.

STUDY DESIGN AND SETTING

Meta-analysis of randomized controlled trials (RCTs) comparing liberal vs restrictive transfusion strategies in cardiac surgery and acute myocardial infarction patients. The outcome of interest was 30-day or in-hospital mortality.

RESULTS

In cardiac surgery, the pooled risk ratio for mortality was 0.83 (95% confidence interval [CI] 0.62-1.12, P = .22) times lower in the restrictive group when compared to the liberal group in trials applying a transfusion strategy throughout the patient's entire perioperative period, and 1.33 (95% CI 0.84-2.11, P = .22) times higher in the restrictive group in trials not applying transfusion strategies throughout the entire perioperative period. When combined, the risk ratio for mortality was 0.98 (95% CI 0.73-1.32, P = .89). In patients with acute myocardial infarction, the risk ratio for mortality was 0.72 (95% CI 0.40-1.28, P = .26) times lower in the restrictive group when compared to the liberal group in 1 trial excluding patients administered the intervention prerandomization and 1.19 (95% CI 0.96-1.47, P = .11) times higher in the restrictive group in 1 trial including patients receiving the intervention prerandomization. When combined the risk ratio for mortality was 1.00 (0.62-1.59, P = .99).

CONCLUSION

Though not statistically significant, there was a consistent difference in trends between RCTs administering significant numbers of transfusion outside the trial study period compared to those that did not. The implications of our results may extend to RCTs in other settings that ignore if and how frequently an investigated therapy is administered outside the trial window.

Consensus of the Brazilian association of hematology, hemotherapy and cellular therapy on patient blood management: History and scenario of patient blood management in the world and in Brazil

Patient Blood Management (PBM) is a multidimensional approach that seeks to optimize the use of blood and its components in patients. This matter emerged as a response to the need to reduce unnecessary exposure to blood transfusions and their potential risks. In the past, blood transfusion was often overused resulting in complications and high costs. The advent of Patient Blood Management has caused a paradigm shift, highlighting anemia prevention, bleeding control and maximizing the production of blood cells by the organism itself. Patient Blood Management guidelines include the early identification of anemia, strategies to minimize blood loss during surgery, intraoperative blood conservation techniques, preoperative hemoglobin optimization and evidence-based approaches to the rational use of blood transfusions. Aiming to improve clinical outcomes, decrease transfusion-related complications and reduce associated costs, this multidisciplinary approach counts on doctors, nurses, pharmacists and other healthcare professionals. Based on research and clinical evidence, Patient Blood Management continues to evolve thereby promoting safer, more effective patient-centered practices. Its implementation has proven beneficial in various medical contexts thereby contributing to improvements in the quality of care provided to patients. Our goal with this Consensus is to present readers with a broad and diverse view of Patient Blood Management so that they have the building blocks to implement this new technique.

Patient Blood Management: Improving Outcomes for Millions While Saving Billions. What Is Holding It Up?

Patient blood management (PBM) offers significantly improved outcomes for almost all medical and surgical patient populations, pregnant women, and individuals with micronutrient deficiencies, anemia, or bleeding. It holds enormous financial benefits for hospitals and payers, improves performance of health care providers, and supports public authorities to improve population health. Despite this extraordinary combination of benefits, PBM has hardly been noticed in the world of health care. In response, the World Health Organization (WHO) called for its 194 member states, in its recent Policy Brief, to act quickly and decidedly to adopt national PBM policies. To further support the WHO's call to action, this article addresses 3 aspects in more detail. The first is the urgency from a health economic perspective. For many years, growth in health care spending has outpaced overall economic growth, particularly in aging societies. Due to competing economic needs, the continuation of disproportionate growth in health care spending is unsustainable. Therefore, the imperative for health care leaders and policy makers is not only to curb the current spending rate relative to the gross domestic product (GDP) but also to simultaneously improve productivity, quality, safety of patient care, and the health status of populations. Second, while PBM meets these requirements on an exceptional scale, uptake remains slow. Thus, it is vital to identify and understand the impediments to broad implementation. This includes systemic challenges such as the so-called "waste domains" of failure of care delivery caused by malfunctions of health care systems, failure of care coordination, overtreatment, and low-value care. Other impediments more specific to PBM are the misperception of PBM and deeply rooted cultural patterns. Third, understanding how the 3Es-evidence, economics, and ethics-can effectively be used to motivate relevant stakeholders to take on their respective roles and responsibilities and follow the urgent call to implement PBM as a standard of care.

Perioperative inappropriate red blood cell transfusions significantly increase total costs in elective surgical patients, representing an important economic burden for hospitals

Background

Red blood cell (RBC) transfusions in surgical patients are associated with increased morbidity a hospital stay. However, little is known about how clinical and economic outcomes differ between appropriately and inappropriately transfused patients. We hypothesized that inappropriate RBC transfusions in elective surgical patients would significantly increase hospital cost. The aim of this study was to quantify the economic burden associated with inappropriate RBC transfusions.

Methods

We retrospectively included all adult patients admitted for elective non-cardiac surgery between January 2014 and March 2020. Patients were divided into three groups (not transfused, appropriately transfused and inappropriately transfused). The primary outcome was the excess in hospital cost in patients inappropriately transfused compared to non-transfused patients. Costs were calculated using a bottom–up approach and involving cost calculation on a granular level. According to international guidelines, transfusions were considered appropriate if administered with an ASA score of 1–2 and the last hemoglobin level measured before transfusion < 70 g/L, or with an ASA score ≥ 3 and the last hemoglobin level < 80 g/L. Cases where RBC transfusions were deemed necessary regardless of the Hb levels were reviewed by the patient blood management (PBM) board and classified accordingly. Secondary outcomes included total transfusion rate, transfusion index, and length of hospital stay. Statistical analysis was carried out by multivariable regression models.

Results

During the study period there were 54,922 consecutive surgical admissions, of these 1,997 received an RBC transfusion, with 1,125 considered inappropriate. The adjusted cost of each inappropriate RBC transfusions was estimated in United States dollars (USD) 9,779 (95% CI, 9,358 – 10,199; p < 0.001) and totaled USD 11,001,410 in our series. Inappropriately transfused patients stayed 1.6 times (95% CI, 1.5–1.6; p < 0.001) longer in hospital (10.6 days vs. 6.7 days) than non-transfused patients and a mean 2.35 RBC units per patient were administered.

Conclusion

Inappropriate RBC transfusions in elective surgical patients seem to be common and may represent a significant economic burden. In our experience, inappropriate transfusions significantly increased hospital costs by an average of USD 9,779 compared to non-transfused patients. Through specific PBM policy, hospitals may improve cost-effectiveness of their elective surgical activity by lowering inappropriate transfusions.

External validation of lung function predictions in real-world cohorts of COPD

BACKGROUND

An individualized FEV₁ prediction model has recently been developed based on the Lung Health Study (LHS). An ongoing evaluation of the utility of prediction models in representative settings outside the setup of clinical trials is needed.

OBJECTIVE

To evaluate the external validity of the LHS FEV₁ prediction model in a representative sample of Canadian ever-smoker COPD patients.

METHODS

We used the sample of ever-smokers with spirometrically-confirmed COPD from the Canadian Cohort of Obstructive Lung Disease (CanCOLD), an ongoing prospective, longitudinal, multicenter population-based cohort study. We compared the mean predicted against the mean observed FEV₁ at follow-up visits. We calculated the root mean square error (RMSE) and the actual coverage probability of the 95% individualized prediction intervals.

RESULTS

The final CanCOLD sample consisted of 360 ever-smoker COPD patients, contributing to 970 FEV₁ observations over an average of 3 years of follow-up (standard deviation (SD): 0.6 years). The mean observed vs. predicted FEV₁ for the first follow-up visit (1.67 years from baseline) was 2.28L vs. 2.28L, and for the second visit (3.13 years from baseline) was 2.19L vs. 2.18L. The RMSE of the predictions was 0.205L, and the actual coverage probability of the 95% prediction intervals was 93%. The model had a similar performance across multiple subgroups.

CONCLUSIONS

The model showed robust performance in predicting FEV₁ in the entire sample and in several subgroups of CanCOLD. Our results demonstrate that LHS predictions are valid for at least three years in the general COPD population.

Independent Supported Housing for non-homeless individuals with severe mental illness: Comparison of two effectiveness studies using a randomised controlled and an observational study design

BACKGROUND

No randomised controlled study (RCT) on the effectiveness of Independent Supported Housing (ISH) vs. housing as usual (HAU) settings for non-homeless individuals with severe mental illness (SMI) has been conducted to date because of limited feasibility. Alternative designs, such as observational studies, might be suitable for providing adequate evidence if well conducted. To test this hypothesis, this article reports on a prospective, direct comparison of the designs of two parallel studies in this field.

METHODS

A two-centre, parallel-group non-inferiority effectiveness study was conducted at two locations in Switzerland using identical instruments and clinical hypotheses. One centre applied an RCT design and the other an observational study (OS) design with propensity score methods (ClinicalTrials.gov: NCT03815604). The comparability of the two study centres was investigated in terms of participants, procedures, and outcomes. The primary outcome was social inclusion and the secondary outcomes were quality of life and psychiatric symptoms.

RESULTS

The study included 141 participants (RCT: n = 58; OS: n = 83). Within one year, 27% study dropouts occurred (RCT: 34%; OS: 22%). A similar balance of sample characteristics was achieved in the RCT and the OS using propensity score methods (inverse probability of treatment weighting). After one year, ISH was non-inferior to the control condition regarding social inclusion (mean differences [95% CI]) in the RCT (6.28 [-0.08 to 13.35]) and the OS (2.24 [-2.30 to 6.77]) and showed no significant differences in quality of life (RCT: 0.12 [-0.52 to 0.75]; OS: 0.16 [-0.26 to 0.58]) and symptoms (RCT: -0.18 [-0.75 to 0.40]; OS: 0.21 [-0.17 to 0.60]) in both study centres. However, strong and persistent preferences for ISH in the RCT control group reduced participants' willingness to participate. Because of several limitations in the RCT, the results of the RCT and the OS are not comparable.

CONCLUSION

Participants were comparable in both study sites. However, there were significant problems in conducting the RCT because of strong preferences for ISH. The OS with propensity score methods provided results of more stable groups of participants and revealed balanced samples and valid outcome analysis. Our results do not support further investment in RCTs in this field.

Prophylactic Probiotic Supplementation for Preterm Neonates-A Systematic Review and Meta-Analysis of Nonrandomized Studies

Systematic review and meta-analyses of randomized controlled trials (RCTs) show that probiotics reduce the risk of necrotizing enterocolitis (NEC ≥ Stage II), late onset sepsis (LOS), all-cause mortality, and feeding intolerance in preterm neonates. Data from observational studies is important to confirm probiotic effects in clinical practice. We aimed to compare outcomes before and after implementing routine probiotic supplementation (RPS) in preterm neonates (<37 weeks of gestation) by performing a systematic review of non-RCTs using Cochrane methodology. Databases including PubMed, The Cumulative Index to Nursing and Allied Health Literature (CINAHL), Embase, Cochrane Central library, and Google Scholar were searched in May 2020. A meta-analysis was performed using a random effects model. Categorical measure of effect size was expressed as OR and 95% CI. Statistical heterogeneity was assessed by the chi-squared test, I2 statistic. The level of evidence (LOE) was summarized using GRADE (Grading of Recommendations Assessment, Development, and Evaluation) guidelines. Primary outcomes were NEC ≥ Stage II, LOS, and all-cause mortality. Secondary outcomes included probiotic sepsis. Thirty good-quality non-RCTs (n = 77,018) from 18 countries were included. The meta-analysis showed RPS was associated with significantly reduced: 1) NEC ≥ Stage II (30 studies, n = 77,018; OR: 0.60; 95% CI: 0.50, 0.73; P <0.00001, I2: 65%; LOE: Moderate), 2) LOS: (21 studies, n = 65,858; OR: 0.85; 95% CI: 0.74, 0.97; P = 0.02, I2: 74%; LOE: Low), and 3) all-cause mortality (27 non-RCTs, n = 70,977; OR: 0.77; 95% CI: 0.68, 0.88; P = 0.0001, I2: 49%; LOE: Low). Subgroups: 1) extremely low birth weight (ELBW: birth weight <1000 g) neonates: RPS was associated with significantly reduced NEC ≥ Stage II (4.5% compared with 7.9%). However, there was no difference in LOS and mortality. 2) Multistrain RPS was more effective than single strain. One study reported 3 nonfatal cases of probiotic sepsis. In summary, moderate- to low-quality evidence indicates that RPS was associated with significantly reduced NEC ≥ Stage II, LOS, and all-cause mortality in neonates <37 weeks of gestation and NEC ≥ Stage II in ELBW neonates.

Randomized Controlled Immunotherapy Clinical Trials for GBM Challenged

Simple Summary

Although multiple meta-analyses on active specific immunotherapy treatment for glioblastoma multiforme (GBM) have demonstrated a significant prolongation of overall survival, no single research group has succeeded in demonstrating the efficacy of this type of treatment in a prospective, double-blind, placebo-controlled, randomized clinical trial. In this paper, we explain how the complexity of the tumor biology and tumor–host interactions make proper stratification of a control group impossible. The individualized characteristics of advanced therapy medicinal products for immunotherapy contribute to heterogeneity within an experimental group. The dynamics of each tumor and in each patient aggravate comparative stable patient groups. Finally, combinations of immunotherapy strategies should be integrated with first-line treatment. We illustrate the complexity of a combined first-line treatment with individualized multimodal immunotherapy in a group of 70 adults with GBM and demonstrate that the integration of immunogenic cell death treatment within maintenance chemotherapy followed by dendritic cell vaccines and maintenance immunotherapy might provide a step towards improving the overall survival rate of GBM patients.

Abstract

Immunotherapies represent a promising strategy for glioblastoma multiforme (GBM) treatment. Different immunotherapies include the use of checkpoint inhibitors, adoptive cell therapies such as chimeric antigen receptor (CAR) T cells, and vaccines such as dendritic cell vaccines. Antibodies have also been used as toxin or radioactive particle delivery vehicles to eliminate target cells in the treatment of GBM. Oncolytic viral therapy and other immunogenic cell death-inducing treatments bridge the antitumor strategy with immunization and installation of immune control over the disease. These strategies should be included in the standard treatment protocol for GBM. Some immunotherapies are individualized in terms of the medicinal product, the immune target, and the immune tumor–host contact. Current individualized immunotherapy strategies focus on combinations of approaches. Standardization appears to be impossible in the face of complex controlled trial designs. To define appropriate control groups, stratification according to the Recursive Partitioning Analysis classification, MGMT promotor methylation, epigenetic GBM sub-typing, tumor microenvironment, systemic immune functioning before and after radiochemotherapy, and the need for/type of symptom-relieving drugs is required. Moreover, maintenance of a fixed treatment protocol for a dynamic, deadly cancer disease in a permanently changing tumor–host immune context might be inappropriate. This complexity is illustrated using our own data on individualized multimodal immunotherapies for GBM. Individualized medicines, including multimodal immunotherapies, are a rational and optimal yet also flexible approach to induce long-term tumor control. However, innovative methods are needed to assess the efficacy of complex individualized treatments and implement them more quickly into the general health system.

Alternative causal inference methods in population health research: Evaluating tradeoffs and triangulating evidence

Population health researchers from different fields often address similar substantive questions but rely on different study designs, reflecting their home disciplines. This is especially true in studies involving causal inference, for which semantic and substantive differences inhibit interdisciplinary dialogue and collaboration. In this paper, we group nonrandomized study designs into two categories: those that use confounder-control (such as regression adjustment or propensity score matching) and those that rely on an instrument (such as instrumental variables, regression discontinuity, or differences-in-differences approaches). Using the Shadish, Cook, and Campbell framework for evaluating threats to validity, we contrast the assumptions, strengths, and limitations of these two approaches and illustrate differences with examples from the literature on education and health. Across disciplines, all methods to test a hypothesized causal relationship involve unverifiable assumptions, and rarely is there clear justification for exclusive reliance on one method. Each method entails trade-offs between statistical power, internal validity, measurement quality, and generalizability. The choice between confounder-control and instrument-based methods should be guided by these tradeoffs and consideration of the most important limitations of previous work in the area. Our goals are to foster common understanding of the methods available for causal inference in population health research and the tradeoffs between them; to encourage researchers to objectively evaluate what can be learned from methods outside one's home discipline; and to facilitate the selection of methods that best answer the investigator's scientific questions.

Efficacy, Safety and Long-term Outcomes of Nicorandil Use in Patients with Stable Ischemic Heart Disease According to the Results of Randomized and Observational Studies

Working Group of the NIKEA Study. Yekaterinburg: Akulina E.N., Reznik I.I.; Izhevsk: Grebnev S.A., Yezhov A., Shinkareva S.E.; Krasnodar: Kudryashov E.A., Skibitsky A.V., Skibitsky V.V., Fendrikova A.V.; Krasnoyarsk: Altayev V.D., Matyushin G.V., Nemik D.B., Pitaev R.R., Samokhvalov E.V., Stolbikov Yu.Yu.; Moscow: Balashov I.S., Voronina V.P., Gaisenok O.V., Dmitrieva N.A., Zagrebelny A.V., Zakharova A.V., Zelenova T.I., Kolganova E.V., Leonov A.S., Lerman O.V., Maximova M.A., Sladkova T.A., Shestakova G.N.; Novosibirsk: Kuimov A.D., Shurkevich A.A.; Omsk: Goodilin V.A., Loginova E.N., Nechaeva G.I.; Orel: Zhuravleva L.L., Lobanova G.N., Luneva M.M., Mitroshina T.N.; Orenburg: Kondratenko V.Yu., Libis R.A.; Rostov-on-Don: Dubishcheva N.F., Kalacheva N.M., Kolomatskaya O.E., Romadina G., Skarzhinskaya N.S., Chesnikova A.I., Chugunova I.B.; Ryazan: Dobrynina N.V., Nikolaev A.S., Trofimova Ya.M., Yakushin S.S.; Tula: Berberfish L.D., Gomova T.A., Gorina G.I., Dabizha V.G., Zubareva L.A., Nadezhkina K.N., Nikitina V.F., Renko I.E., Soin I.A., Yunusova K.N.

Background. Nicorandil is an antianginal drug for which, the ability to positively influence the prognosis of patients (pts) with stable ischemic heart disease (IHD) was confirmed in a randomized controlled trial (RCT) of IONA (the Impact Of Nicorandil in Angina). To study whether the results of RCTs are reproduced in real clinical practice seems to be an actual scientific and practical task.

Aim. To compare the data on the effectiveness and safety of nicorandil in pts with stable IHD obtained in the NIKEA observational study (OS) and in the IONA randomized study.

Material and methods. 590 pts with IHD and stable angina pectoris were included in the OS NIKEA. All pts were recommended to take nicorandil in addition to the standard antiischemic therapy. 21 months after being included in the study, 524 pts received a phone call. During the telephone contact with pts or their relatives, the life status of pts was determined. According to these results of the survey data were obtained, that 15 people died and 509 pts were alive. The events included in the primary combined endpoint (PCEP) were also determined: death from all causes, new cases of acute myocardial infarction and acute cerebrovascular accident, unscheduled operations of myocardial revascularization, hospitalization for decompensation of chronic heart failure, atrial fibrillation, unstable angina, information on taking nicorandil and other drug therapy, adverse events of drug treatment have been reported. A comparative analysis of the results of the OS NIKEA and RCT IONA was carried out. The results of the IONA study were taken according to the publication in the Lancet 2002. A comparative analysis of the results of the effectiveness of nicorandil in real practice (according to the OS results) was performed with the data obtained in the RCT: the nicorandil/placebo groups in the RCT were compared with the adherent/non-adherent nicorandil groups in the OS.

Results. The follow-up duration in both studies was similar and averaged 1.6±0.5 years at RCT IONA and 1.8±0.4 years at NIKEA study. The average age of pts was 67,0±8,0 years in RCT and 65.1±9.6 years in OS. In pts of OS more pronounced comorbidity was noted (cardiovascular diseases, diabetes mellitus). Drugs that favorably affect the prognosis in pts with IHD were more often prescribed to NIKEA study pts (p<0.05). In both RCTs and OS, the antianginal effectiveness of nicorandil was confirmed. According to the OS results, a reduction in the number of angina attacks and a decrease in the need for short-acting nitrates were demonstrated. The frequency of PCEP components was higher in RCT.

Conclusion. Long-term outcomes according to the NIKEA observational program for various components of the PCEP turned out to be similar to the results of RCT IONA. It is demonstrated the efficacy of nicorandil in real clinical practice. 

Sepsis calculator for neonatal early onset sepsis - a systematic review and meta-analysis

BACKGROUND

Over investigation and overuse of empirical antibiotics is a concern in management of neonatal early onset sepsis (EOS) using the Centers for Disease Control and Prevention guidelines. "Sepsis calculator" is a risk-based prediction model for managing neonates at risk of EOS.

OBJECTIVE

To compare outcomes of neonatal EOS using of sepsis calculator versus conventional approach.

METHODS

A systematic review of randomized controlled trials (RCT) and non-RCTs reporting on outcomes after implementation of sepsis calculator for EOS for neonates >34-week gestation was conducted using the Cochrane methodology. Databases PubMed, CINAHL, Embase, Cochrane Central library and Google Scholar were searched in May 2019. Primary outcomes were antibiotics usage and laboratory tests for managing EOS. Secondary outcomes included hospital admissions and readmissions, blood culture positive EOS and mortality. The level of evidence (LOE) was summarized using the GRADE guidelines.

RESULTS

A total of 387 articles were retrieved after initial search. Six high quality non-RCTs fulfilled inclusion criteria. Meta-analysis (random effects model) showed that implementation of sepsis calculator was associated with reduced antibiotic usage [N = 172,385; OR = 0.22 (0.14-0.36); p < .00001; heterogeneity (I²) = 97%, Number needed to treat (NNT): 22], laboratory tests [N = 168,432; OR = 0.14 (0.08-0.27); p < .00001; I² = 99%, NNT = 8], and admissions to neonatal unit [N = 16,628; OR = 0.24 (0.11-0.51); p = .0002; I² = 98%, NNT = 7]; LOE: moderate. There was no difference in mortality, culture positive EOS, and readmissions.

CONCLUSION

Moderate quality evidence indicates that the implementation of a sepsis calculator was associated with reduced usage of antibiotics, laboratory tests and admission to neonatal unit with no increase in mortality and readmissions.

The prognostic role of perioperative allogeneic blood transfusions in gastric cancer patients undergoing curative resection: A systematic review and meta-analysis of non-randomized, adjusted studies

The impact of allogeneic perioperative blood transfusions (APTs) on the prognosis of gastric cancer patients undergoing curative-intent gastrectomy is still a highly debated topic. Two meta-analyses were published in 2015, and new studies report conflicting results. A literature review was conducted using PubMed, Scopus, the Cochrane Central Register of Controlled Trials and the Cochrane Database of Systematic Reviews, updated to March 1, 2016. Thirty-eight non-randomized studies reporting data on overall survival (OS), disease-free survival (DFS), disease-specific survival (DSS) and postoperative complications (PCs) were included. An inverse variance random-effects meta-analysis was conducted. APTs showed an association with worse OS, DFS, DSS and an increased number of PCs. The hazard ratio (HR) for OS was 1.49, with a 95% confidence interval (95% CI) of 1.32-1.69 (p < .00001; Q-test p = .001, I-squared = 56%). After outlier exclusion, the HR for OS was 1.34 (95% CI = 1.23-1.45, p < .00001; Q-test p = .64, I-squared = 0%). The HR for DFS was 1.48 (95% CI = 1.18-1.86, p = .0007; Q-test p = .31, I-squared = 16%), and the HR for DSS was 1.66 (95% CI = 1.5-2.19, p = .0004; Q-test p = .96, I-squared = 0%). The odds ratio for PCs was 3.33 (95% CI = 2.10-5.29, p < .00001; Q-test p = .14, I-squared = 42%). This meta-analysis showed a significant association between transfusions and OS, DFS, DSS and PCs. The quality of the evidence was low. Aggregation, selection and selective reporting bias were detected. The biases shifted the results towards significance. Further studies using accurate adjustment methods are needed. Until such additional studies are performed, caution in administering transfusions and optimization of cancer patient blood management are warranted.

Randomized controlled trials vs. observational studies: why not just live together?

Randomized controlled trials (RCTs) are considered the gold standard for clinical research, thus having a high impact on clinical guidelines and our daily patients’ care. However, various treatment strategies which we consider “evidence based” have never been subject to a prospective RCT, as we would rate it unethical to withheld an established treatment to individuals in an placebo controlled trial.

In a recent BMC Anesthesiology publication, Trentino et al. analyzed the usefulness of observational studies in assessing benefit and risk of different transfusion strategies. The authors nicely reviewed and summarized similarities and differences, advantages and limitations, between different study types frequently used in transfusion medicine. In this interesting article, the authors conclude, that ‘when comparing the results of observational studies with RCTs assessing transfusion outcomes, it is important that one consider not only the study method, but also the key elements of the study design’. Thus, in this commentary we now discuss the pro’s and con’s of different study types, even irrespective of transfusion medicine.