Can propensity score matching replace randomized controlled trials?

Randomized controlled trials(RCTs)have long been recognized as the gold standard for establishing causal relationships in clinical research.Despite that,various limitations of RCTs prevent its widespread implementation,ranging from the ethicality of withholding potentially-lifesaving treatment from a group to relatively poor external validity due to stringent inclusion criteria,amongst others.However,with the introduction of propensity score matching(PSM)as a retrospective statistical tool,new frontiers in establishing causation in clinical research were opened up.PSM predicts treatment effects using observational data from existing sources such as registries or electronic health records,to create a matched sample of participants who received or did not receive the intervention based on their propensity scores,which takes into account characteristics such as age,gender and comorbidities.Given its retrospective nature and its use of observational data from existing sources,PSM circumvents the aforementioned ethical issues faced by RCTs.Majority of RCTs exclude elderly,pregnant women and young children;thus,evidence of therapy efficacy is rarely proven by robust clinical research for this population.On the other hand,by matching study patient characteristics to that of the population of interest,including the elderly,pregnant women and young children,PSM allows for generalization of results to the wider population and hence greatly increases the external validity.Instead of replacing RCTs with PSM,the synergistic integration of PSM into RCTs stands to provide better research outcomes with both methods complementing each other.For example,in an RCT investigating the impact of mannitol on outcomes among participants of the Intensive Blood Pressure Reduction in Acute Cerebral Hemorrhage Trial,the baseline characteristics of comorbidities and current medications between treatment and control arms were significantly different despite the randomization protocol.Therefore,PSM was incorporated in its analysis to create samples from the treatment and control arms that were matched in terms of these baseline characteristics,thus providing a fairer comparison for the impact of mannitol.This literature review reports the applications,advantages,and considerations of using PSM with RCTs,illustrating its utility in refining randomization,improving external validity,and accounting for non-compliance to protocol.Future research should consider integrating the use of PSM in RCTs to better generalize outcomes to target populations for clinical practice and thereby benefit a wider range of patients,while maintaining the robustness of randomization offered by RCTs.

Endovenous laser treatment vs conventional surgery for great saphenous vein varicosities: A propensity score matching analysis

BACKGROUND Varicosis is a common venous condition,which is typically treated surgically.However,selection of the optimal surgical approach can be challenging.Previous studies comparing endovenous laser treatment(EVLT)and conventional surgery were retrospective and observational in nature and the results may therefore have been influenced by selection bias and the presence of other confounding factors.In this study,we used propensity score matching to reduce selection bias when comparing EVLT and conventional surgery for the treatment of varicose great saphenous veins.METHODS We retrospectively reviewed the records of 1063 patients treated for primary varicosis of the great saphenous vein at the Second Affiliated Hospital of Xuzhou Medical University between January 2009 and December 2019.Among them,56 patients were excluded owing to additional small saphenous varicose vein involvement,81 owing to recurring varicose veins,83 owing to complicated varicose veins(CEAP clinical classification C5-C6),and 6 owing to perioperative phlebitis.Finally,772 patients were enrolled in this study.Standard demographic and clinicopathological data were collected from the medical records of the patients.For propensity score matching,522 patients(261 who underwent EVLT and 261 who underwent conventional surgery)were randomly matched 1:1 by age,sex,onset time,smoking status,presence of diabetes,family history,stress therapy,C class,and the affected leg.RESULTS Of the 772 patients included in the study,467 underwent EVLT and 305 underwent conventional surgery.There were significant differences in age,onset time,smoking and diabetes status,and family history between the two groups.Following propensity score matching,no significant differences in patients’characteristics remained between the two groups.ELVT was associated with a shorter operation time and hospital stay than conventional surgery,both before and after propensity score matching.There were no differences in complications between the two groups after propensity score matching.Patients who underwent EVLT had a higher recurrence rate during the two-year follow-up period than those who underwent conventional surgery(33.33%vs 21.46%,χ^(2)=11.506,P=0.001),and a greater percentage of patients who underwent EVLT experienced pain one week after the procedure(39.85%vs 19.54%,P=0.000).CONCLUSION EVLT may not always be the best option for the treatment of great saphenous vein varicosis.

Does gastric stump cancer really differ from primary proximal gastric cancer? A multicentre, propensity score matching-used, retrospective cohort study

BACKGROUND Although the location of proximal cancer of the remnant stomach is the same as that of primary proximal cancer of the stomach,its clinical characteristics and prognosis are still controversial.AIM To evaluate the clinicopathological features and prognosis factors of gastric stump cancer(GSC)and primary proximal gastric cancer(PGC).METHODS From January,2005 to December,2016,178 patients with GSC and 957 cases with PGC who received surgical treatment were enrolled.Patients in both groups underwent 1:1 propensity score matching analysis,and both clinical and pathological data were systematically collected for statistical purposes.Quality of RESULTS One hundred and fifty-two pairs were successfully matched after propensity score matching analysis.Of the 15 demographic and pathological variables collected,the analysis further revealed that the number of lymph nodes and positive lymph nodes were different prognostic and clinicopathological factors between PGC and GSC.Univariate and multivariate analyses showed that gender,differentiation degree and tumor-node-metastasis stage were independent risk factors for patients with GSC.Gender,vascular invasion,differentiation degree,depth of infiltration,positive lymph nodes,and tumor-node-metastasis stage were independent risk factors for patients with PGC.The 5-year overall survival and cancer-specific survival of patients with GSC were significantly lower than those in the PGC group,the scores for overall quality of life in the GSC-malignant group were lower than the GSC-benign,and the differences were statistically significant.CONCLUSION The differences in clinicopathological characteristics between GSC and PGC were clarified,and PGC had a better prognosis than GSC.

Effects of Continuous Non-Invasive Blood Pressure Monitoring on Intraoperative Hemodynamics and Postoperative Myocardial Injury in Craniotomy:Comparison Between Groups Based on Self-Control and Propensity Score Matching

Objective:To explore the effect of continuous non-invasive blood pressure monitoring on intraoperative hemodynamics and postoperative myocardial injury in craniotomy.Methods:120 cases of elective craniotomy were divided into the self-control group(continuous non-invasive blood pressure monitoring and intermittent cuff non-invasive blood pressure monitoring,CNAP group)and propensity score matching group(only intermittent cuff non-invasive blood pressure measurement in previous craniotomy,PSM group);Goal-directed hemodynamic management in CNAP group included heart rate(HR),blood pressure(BP),stroke volume(SV),stroke variability(SVV),and systemic vascular resistance index(SVRI).The main index is to compare the troponin level within 72 hours after operation between the CNAP group and the PSM group;The secondary indicators are the comparison of the hemodynamic conditions between the CNAP group and the PSM at 10 specific time points.Results:The incidence of postoperative myocardial injury in the CNAP group was significantly lower than that in the PSM group(12%vs.30%,P=0.01);in the CNAP group hypotensive episodes(6 vs.3,P=0.01),positive balance of fluid therapy(700 vs.500 mL,P<0.001),more use of vasoactive drugs(29 vs.18,P=0.04),more stable hemodynamics medical status(P=0.03)were recorded.Conclusion:The hemodynamic management strategy based on continuous non-invasive blood pressure monitoring can reduce the incidence of myocardial injury after elective craniotomy and maintain a more stable hemodynamic state.

Progress in hepatitis B virus-related acute-on-chronic liver failure treatment in China:A large,multicenter,retrospective cohort study using a propensity score matching analysis

Background:Hepatitis B virus-related acute-on-chronic liver failure(HBV-ACLF)has a high short-term mortality.However,the treatment progression for HBV-ACLF in China in the past decade has not been well characterized.The present study aimed to determine whether the HBV-ACLF treatment has significantly improved during the past decade.Methods:This study retrospectively compared short-term(28/56 days)survival rates of two different nationwide cohorts(cohort I:2008-2011 and cohort II:2012-2015).Eligible HBV-ACLF patients were enrolled retrospectively.Patients in the cohorts I and II were assigned either to the standard medical therapy(SMT)group(cohort I-SMT,cohort II-SMT)or artificial liver support system(ALSS)group(cohort IALSS,cohort II-ALSS).Propensity score matching analysis was conducted to eliminate baseline differences,and multivariate logistic regression analysis was used to explore the independent factors for 28-day survival.Results:Short-term(28/56 days)survival rates were significantly higher in the ALSS group than those in the SMT group(P<0.05)and were higher in the cohort II than those in the cohort I(P<0.001).After propensity score matching,short-term(28/56 days)survival rates were higher in the cohort II than those in the cohort I for both SMT(60.7%vs.53.0%,50.0%vs.39.8%,P<0.05)and ALSS(66.1%vs.56.5%,53.0%vs.44.4%,P<0.05)treatments.The 28-day survival rate was higher in patients treated with nucleos(t)ide analogs than in patients without such treatments(P=0.046).Multivariate logistic regression analysis revealed that ALSS(OR=0.962,95%CI:0.951-0.973,P=0.038),nucleos(t)ide analogs(OR=0.927,95%CI:0.871-0.983,P=0.046),old age(OR=1.028,95%CI:1.015-1.041,P<0.001),total bilirubin(OR=1.002,95%CI:1.001-1.003,P=0.004),INR(OR=1.569,95%CI:1.044-2.358,P<0.001),COSSH-ACLF grade(OR=2.683,95%CI:1.792-4.017,P<0.001),and albumin(OR=0.952,95%CI:0.924-0.982,P=0.002)were independent factors for 28-day mortality.Conclusions:The treatment for patients with HBV-ACLF has improved in the past decade.

Survival difference between EGFR Del19 and L858R mutant advanced non-small cell lung cancer patients receiving gefitinib:a propensity score matching analysis

Objective： Although superior clinical benefits of epidermal growth factor receptor （EGFR） tyrosine kinase inhibitors （TKIs） in the treatment of advanced non-small-cell lung cancer （NSCLC） had been reported, the survival difference between exon 19 deletion （Dell9） and exon 21 Leu858Arg substitution （L858R） remains controversial. The purpose of this study is to investigate the differences in progression-free survival （PFS） and overall survival （OS） between different EGFR mutant subtypes among advanced NSCLC patients receiving gefitinib. Methods： There were 204 advanced NSCLC patients with EGFR mutations treated with gefitinib were enrolled in this retrospective cohort study. Patients were divided into the EGFR Dell9 group and the L858R mutated group according to their mutant subtype. Propensity score matching （PSM） was conducted by using a nearest-neighbor algorithm （1：1） to adjust for demographical and clinical covariates. Survival curves were constructed with the Kaplan-Meier method and compared by using the log-rank test. Results： The PFS in Dell9 group was similar to that in the L858R group [before PSM 8.6 vs. 7.2 months, P=0.072; after PSM 7.3 vs. 7.2 months, P=0.155]. No differences were detected in OS between the L858R and the Dell9 group （before PSM 17.8 vs. 13.1 months, P=0.253; after PSM 16.9 vs. 13.1 months, P=0.339）. The Dell9 group was significantly younger compared with the L858R mutation group in age （P=0.015）. Conclusions： No significant difference was found in the PFS or OS between the Dell9 and L858R mutant NSCLC patients receiving gefitinib. The age gap might contribute to the survival differences between Dell9 and L858R groups. PSM is of important value to the elimination of potential bias.

Cholecystectomy is associated with higher risk of recurrence after microwave ablation of hepatocellular carcinoma:a propensity score matching analysis

Objective:To explore the association between cholecystectomy and the prognostic outcomes of patients with hepatocellular carcinoma(H CC)who underwent microwave ablation(MWA).Methods:Patients with HCC(«=921)who underwent MWA were included and divided into cholecystectomy(n=114)and non-cholecystectomy groups(n=807).After propensity score matching(PSM)at a 1:2 ratio,overall survival(OS)and disease-free survival(DFS)rates were analyzed to compare prognostic outcomes between the cholecystectomy(«=114)and non-cholecystectomy groups(n=228).Univariate and multivariate Cox analyses were performed to assess potential risk factors for OS and DFS.Major complications were also compared between the groups.Results:After matching,no significant differences between groups were observed in baseline characteristics.The 1-,3-,and 5-year OS rates were 96.5%,82.1%,and 67.1%in the cholecystectomy group,and 97.4%,85.2%,and 74.4%in the non-cholecystectomy group(P=0.396);the 1-,3-,and 5-year DFS rates were 58.4%,34.5%,and 26.6%in the cholecystectomy group,and 73.6%,44.7%,and 32.2%in the non-cholecystectomy group(P=0.026),respectively.The intrahepatic distant recurrence rate in the cholecystectomy group was significantly higher than that in the non-cholecystectomy group(P=0.026),and the local tumor recurrence and extrahepatic recurrence rates did not significantly differ between the groups(P=0.609 and P=0.879).Multivariate analysis revealed that cholecystectomy(HR=1.364,95%Cl 1.023-1.819,P=0.035),number of tumors(2 vs.1:HR=2.744,95%Cl 1.925-3.912,P<0.001;3 vs.1:HR=3.411,95%Cl 2.021-5.759,P<0.001),and y-GT levels(HR=1.003,95%Cl 1.000-1.006,P<0.024)were independent risk factors for DFS.The best y-GT level cut-off value for predicting median DFS was 39.6 U/L(area under the curve=0.600,P<0.05).A positive correlation was observed between cholecystectomy and y-GT level(r=0.108,95%Cl-0.001-0.214,P=0.047).Subgroup analysis showed that the DFS rates were significantly higher in the non-cholecystectomy group than the cholecystectomy group when Y-GT>39.6 U/L(i3=0.044).The 5-,10-,15-,20-,and 25-year recurrence rates from the time of cholecystectomy were 2.63%,21.93%,42.11%,58.77%,and 65.79%,respectively.A significant positive correlation was observed between cholecystectomy and the time from cholecystectomy to recurrence(r=0.205,95%Cl 0.016-0.379,P=0.029).There were no significant differences in complications between groups(P=0.685).Conclusions:Patients with HCC who underwent cholecystectomy were more likely to develop intrahepatic distant recurrence after MWA,an outcome probably associated with increased y-GT levels.Moreover,the recurrence rates increased with time.

Short-term and middle-term evaluation of laparoscopic hepatectomies compared with open hepatectomies: A propensity score matching analysis

AIM To compare short-term results between laparoscopic hepatectomy and open hepatectomy using a propensity score matching. METHODS A patient in the laparoscopic liver resection(LLR) groupwas randomly matched with another patient in the open liver resection(OLR) group using a 1:1 allocated ratio with the nearest estimated propensity score. Patients of the LLR group without matches were excluded. Matching criteria included age, gender, body mass index, American Society of Anesthesiologists score, potential co-morbidities, hepatopathies, size and number of nodules, preoperative chemotherapy, minor or major liver re-sections. Intraoperative and postoperative data were compared in both groups.RESULTS From January 2012 to January 2015, a total of 241 hepa-tectomies were consecutively performed, of which 169 in the OLR group(70.1%) and 72 in the LLR group(29.9%). The conversion rate was 9.7%(n = 7). The mortality rate was 4.2% in the OLR group and 0% in the LLR group. Prior to and after propensity score matching, there was a statistically significant difference favorable to the LLR group regarding shorter operative times(185 min vs 247.5 min; P = 0.002), less blood loss(100 m L vs 300 m L; P = 0.002), a shorter hospital stay(7 d vs 9 d; P = 0.004), and a significantly lower rate of medical complications(4.3% vs 26.4%; P < 0.001). CONCLUSION Laparoscopic liver resections seem to yield better short-term and mid-term results as compared to open hepatectomies and could well be considered a privileged approach and become the gold standard in carefully selected patients.

Laparoscopic vs open total gastrectomy for advanced gastric cancer following neoadjuvant therapy:A propensity score matching analysis

BACKGROUND Laparoscopic total gastrectomy(LTG)has drawn increasing attention over the years.Although LTG has shown surgical benefits compared to open TG(OTG)in early stage gastric cancer(GC),little is known about the surgical and oncological outcomes of LTG for advanced GC following neoadjuvant therapy(NAT).AIM To compare the long-and short-term outcomes of advanced GC patients who underwent LTG vs OTG following NAT.METHODS Advanced GC patients who underwent TG following NAT between April 2011 and May 2018 at the Cancer Hospital of the Chinese Academy of Medical Sciences were enrolled and stratified into two groups:LTG and OTG.Propensity score matching analysis was performed at a 1:1 ratio to overcome possible bias.RESULTS In total,185 patients were enrolled(LTG:78;OTG:109).Of these,138 were paired after propensity score matching.After adjustment for propensity score matching,baseline parameters were similar between the two groups.Compared to OTG,LTG was associated with a significantly shorter length of hospital stay(P=0.012).The rates of R0 resection,lymph node harvest,and postoperative morbidity did not significantly differ between the two groups.Overall survival(OS)outcomes were comparable between the two groups.Pathological T and N stages were found to be independent risk factors for OS.CONCLUSION LTG can be a feasible method for advanced GC patients following NAT,as it appears to be associated with better short-and comparable long-term outcomes compared to OTG.

Real-world local recurrence rate after cold polypectomy in colorectal polyps less than 10 mm using propensity score matching

BACKGROUND Cold polypectomy(CP)is a simple and safe procedure for polyps less than 10 mm in size;however,there is concern about local recurrence following CP because of unidentified margins of excised specimens and the lack of tumor suppression effect by coagulation.Some clinical trials have evaluated local persistent recurrence;their results suggest that a higher rate of local recurrence has not been documented so far.There were few reports that observed the course over long periods of time after CP in clinical practice.AIM To evaluate the presence of local recurrence following CP and hot polypectomy(HP)using propensity score matching.METHODS We analyzed 275 patients who underwent polypectomy for non-pedunculated colorectal polyps less than 10 mm(959 Lesions)between October 2016 and 2017 and underwent follow-up endoscopy subsequently.We divided them into the CP group(706 Lesions),wherein CP was performed,and the HP group(253 Lesions),wherein HP was performed.Using propensity score matching,we extracted 215 Lesions in each group and evaluated the local recurrence and content of CP in the real clinic and adverse events using medical records.RESULTS After propensity score matching,there were no significant differences in the patients’and their endoscopic background(age,use of antithrombotics,indications,size,morphology,location of polyps,and polypectomy device)between the groups.The mean duration between colorectal polypectomy and the next follow-up colonoscopy was 17.5±7.1(range,6-39)mo in the CP group and 15.7±6.0(range,6-35)mo in the HP group,which was significantly longer in the CP group(P=0.005).The local recurrence rate was 0.93%in the CP group and 0.93%in the HP group,without a significant difference(P=0.688).Additionally,no differences were observed in the macroscopic en bloc resection rate,histopathological complete resection rate,and pathological results between the groups.Adverse events did not occur in either group.CONCLUSION Local recurrence after CP was equivalent to that following HP in clinical practice.CP is useful and safe in the treatment of non-pedunculated polyps of less than 10 mm.

Clinicopathological characteristics and longterm survival of patients with synchronous multiple primary gastrointestinal stromal tumors: A propensity score matching analysis

BACKGROUND Multiple gastrointestinal stromal tumors(MGISTs)are specific and rare.Little is known about the impact of MGISTs on the survival of patients with gastrointestinal stromal tumors(GIST).The diagnosis,treatment and follow-up strategies of MGISTs is not specifically described in guidelines.AIM To compare the clinicopathological characteristics and prognosis of MGISTs and solitary GISTs(SGISTs)METHODS Patients diagnosed with primary GISTs from March 2010 to January 2020 were included.Due to the inhomogeneous distribution of several baseline characteristics and uneven MGIST and SGIST group sizes,propensity score matching was performed according to comorbidities,body mass index,tumor location,mitotic index,sex,age and American Society of Anesthesiologists score.Differences in clinicopathological characteristics and prognosis between patients with MGISTs and patients with SGISTs were compared.RESULTS Among the entire cohort of 983 patients,the incidence of MGISTs was 4.17%.Before matching,patients with MGISTs and those with SGISTs had disparities in body mass index,surgical approach,tumor size and mitotic index.After 1:4 ratio matching,the clinical baseline data were comparable.The 5-year progression-free survival rate was 52.17%in the MGIST group and 75.00%in the SGIST group(P=0.031).On multivariate analysis,tumor location,tumor size,mitotic index,imatinib treatment and MGISTs(hazard ratio=2.431,95%confidence interval=1.097-5.386,P=0.029)were identified as independent prognostic factors of progression-free survival.However,overall survival was similar between the SGIST and MGIST groups.CONCLUSION Patients with MGISTs had poorer progression-free survival than patients with SGISTs.Risk criteria and diagnostic and treatment strategies should be developed to achieve personalized precision therapy and maximize the survival benefit.

Colorectal adenocarcinoma patients with M1a diseases gain more clinical benefits from palliative primary tumor resection than those with M1b diseases: A propensity score matching analysis

BACKGROUND Surgical resection is regarded as the only potentially curative treatment option for patients with metastatic colorectal cancer(CRC).The National Comprehensive Cancer Network clinical practice guidelines do not recommend palliative surgery unless there is a risk of severe symptoms.However,accumulating evidence has shown that palliative surgery is associated with more favorable outcomes for patients with metastatic CRC.AIM To investigate the separate role of palliative primary tumor resection for patients with stage IVA(M1a diseases)and stage IVB(M1b diseases)colorectal adenocarcinoma(CRA).METHODS CRA patients diagnosed from 2010 to 2015 with definite M1a and M1b categories according to the 8th edition of American Joint Committee on Cancer staging system were selected from the Surveillance Epidemiology and End Results(SEER)database.To minimize potential selection bias,the data were adjusted by propensity score matching(PSM).Baseline characteristics,including gender,year of diagnosis,age,marital status,primary site,surgical information,race,grade,chemotherapy,and radiotherapy,were recorded and analyzed.Univariate and multivariate analyses were performed to explore the separate role of palliative surgery for patients with M1a and M1b diseases.RESULTS A total of 19680 patients with metastatic CRA were collected from the SEER database,including 10399 cases of M1a diseases and 9281 cases of M1b diseases.Common independent prognostic factors for both M1a and M1b patients included year of diagnosis,age,race,marital status,primary site,grade,surgery,and chemotherapy.After PSM adjustment,3732 and 3568 matched patients in the M1a and M1b groups were included,respectively.Patients receiving palliative primary tumor resection had longer survival time than those without surgery(P<0.001).For patients with M1a diseases,palliative resection could increase the median survival time by 9 mo;for patients with M1b diseases,palliative resection could prolong the median survival time by 7 mo.For M1a diseases,patients with lung metastasis had more clinical benefit from palliative resection than those with liver metastasis(15 mo for lung metastasis vs 8 mo for liver metastasis,P<0.001).CONCLUSION CRA patients with M1a diseases gain more clinical benefits from palliative primary tumor resection than those with M1b diseases.Those patients with M1a(lung metastasis)have superior long-term outcomes after palliative primary tumor resection.

Association between Self-Rated Health and Depressive Symptoms in Rural Chinese Adults:A Cohort Study Based on Propensity Score Matching

Health status is widely regarded as a correlate of depressive symptoms.However,health assessments based on clinical diagnosis in rural areas with poor medical conditions are very limited.Self-rated health(SRH)serves as a simple and convenient evaluation indicator,which may be used as an independent predictor of depressive symptoms.To confirm the relationship between SRH and depressive symptoms in rural adults,a longitudinal survey of rural households in China was conducted using the China Family Panel Studies(CFPS)from 2012 to 2016.Propensity score matching and logistic regression analysis were used to explore the association.After data cleansing,3,127 pairs(6,254 participants)aged 16 and older followed for 4 years were enrolled,of which the average age was(50.02±14.19)years old,and the proportions of male and female were 48.64%and 51.36%,respectively.The incidence rate of depressive symptoms within 4 years was 30.86%(95%CI:29.24–32.48)in the group with fair or poor SRH,and 21.59%(95%CI:20.14–23.03)in the group with good SRH.The difference between the two groups was statistically significant(χ^(2)=69.51,P<0.001).The results of univariate unconditional logistic regression analysis showed that there was a correlation between SRH and depressive symptoms in rural adults aged 30 and above(OR=1.65,95%CI:1.46–1.85,P<0.001).Thus,a simple and practical assessment tool based on SRH and other indicators should be established for early prevention and intervention in rural primary mental health care.

Evaluating the Impact of Adoption of Improved Maize Varieties on Yield in Uganda： A Propensity Score Matching Approach

The main objective of this study was to evaluate the impact of adopting improved maize varieties on crop yield in Uganda using propensity score matching （PSM） algorithms to control for hidden selection bias. The study employed cross-sectional household data collected in 2005/2006 by the Uganda Bureau of Statistics （UBOS） across the country. Data were divided into two parts; the full sample and smallholder farmer sub-sample （those that cultivated less than 5 acres or 2 Hectares of maize in 2004 and 2005）. Then estimation was made of the difference in yields between the adopters and non adopters, the average treatment effect on the treated （ATT） for the full sample and smallholder farmer sub-sample. Matching methods were used to control for hidden selection bias and the standardized bias measure was used to check for the quality of matching. The results indicate that adoption of improved maize seed had a robust positive and significant effect on yields obtained by farmers. The results were consistent for both the full and smallholder farmer sub-samples. Sensitivity analysis using Rosenbaum bounds indicated that the ATT results were fairly robust to hidden selection bias. That is, the results were not sensitive to unobserved selection bias. Therefore it is confidently asserted that the estimated average difference in maize yields between the adopters and non-adopters was due to the effect of planting improved maize seed.

Effects of Health Record Computerization in the Context of the COVID-19 Pandemic in Burundi’ Hospitals: Propensity Score Matching

Introduction: A great number of software are currently used to digitalize the patient records in order to optimize the quality of services offered to patients. The objective of this study was to evaluate the effects of Electronic Health Records use in Burundi’s hospitals, taking into account the COVID-19 pandemic context. Methods: This was a quasi-experimental study based on difference in difference method. Ten district hospitals were included in the study, five of them had the Electronic Health Records and five of which did not yet have the Electronic Health Records. The hospital’s control group were chosen using the propensity score matching method. The period before the project’s implementation was 2014 and the period after were 2019 and 2020. Results: After 5 years of the Electronic Health Record’s implementation, the results showed an increase in outpatient consultation (70%), deliveries (more than 100%), caesarean sections (56%) and major surgeries (43%) indicators. The overall quality score of hospitals’ care had a regressive effect of 37% and the income from performance-based funding had an increase by 31%. The indicators which were affected by the context of the COVID-19 pandemic were especially outpatient consultation, caesarian section, income from performance-based funding decreased by 3%, 5% and 20% respectively. Conclusion: The effects of Electronic Health Records use are effective. As the COVID-19 pandemic impacted the hospital’s indicators negatively, the resilient strategies alongside the potential shocks are recommended.

Effect of male HBV infection on the outcomes of IVF/ICSI cycles:a retrospective cohort study based on propensity score matching

This study aimed to investigate the effects of male hepatitis B virus(HBV)infection on male fertility,embryonic development,and in vitro fertilization/intracytoplasmic sperm injection(IVF/ICSI)outcomes.We performed a retrospective cohort study that included 3965 infertile couples who received fresh embryo transfer cycles for the first time at the Fujian Maternity and Child Health Hospital(Fuzhou,China)from January 2018 to January 2021.Infertile couples were categorized based on their HBV infection status into the HBV group(HBV-positive men and HBV-negative women)and the control group(HBV-negative couples).A 1:1 propensity score matching was performed with relatively balanced covariates.Baseline characteristics,semen parameters,laboratory outcomes,clinical outcomes,and obstetric and neonatal outcomes were compared between groups.After propensity score matching,821 couples were included in each group.Both groups had similar semen parameters and obstetric and neonatal outcomes.The HBV group showed a significantly lower live birth rate than the control group(P<0.05).The HBV group had a significantly higher abortion rate than the control group(P<0.05).The rates of high-quality embryos and blastocyst formation were significantly lower in the HBV group than those in the control group(both P<0.05).In conclusion,in couples who undergo IVF/ICSI,male HBV infection reduces the live birth rate and increases the risk of miscarriage.However,the incidence of low birth weight in women with IVF/ICSI does not increase with male HBV infection.

The Effect of Xu’s Influenza Decoction Combined with Oseltamivir on Influenza A:A Propensity Score Matching Study

Background:The resurgence of seasonal influenza virus circulation has been seen in 2021-2022 after the tempo-rary suppression in 2020-2021.Neuraminidase inhibitors(NAIs)are widely applied in the clinical treatment of influenza A despite several limitations.Objective:To access the efficacy of Xu’s influenza decoction(XID)in combination therapy with oseltamivir for the treatment of influenza A.Methods:In this retrospective cohort study,the eligible participants were diagnosed with influenza A between June 1,2018,and May 30,2022,in the First Affiliated Hospital of Zhejiang Chinese Medical University.According to whether Xu’s influenza decoction was applied,patients were divided into two groups:treated with or without XID.Propensity score matching(PSM)was used to further adjust the covariates between groups.The primary outcome was to compare time to defervescence via K-M curves,Breslow tests,and Cox regression analysis.In Cox proportional hazards model,a univariate analysis was performed to obtain preliminary results,while a further multivariate analysis was conducted to study the independent factors that influence defervescence.Subgroup analysis was conducted according to body temperature and time from onset to admission.The secondary outcome consisted of routine blood and C-reactive protein(CRP),length of stay,and medical costs.Results:A total of 336 patients with influenza A were enrolled in this study(i.e.,163 patients in the XID+oseltamivir group;173 patients in the oseltamivir group).After 1:1 matching via PSM,230 patients meeting the criteria were included in the analysis,with 115 in each arm.The XID+oseltamivir group had shorter time to defervescence(36 h vs 44 h,P=0.011),shorter length of stay(3 days vs 4 days,P=0.018),and higher defervescence possibility(HR=1.384,95%CI:1.054-1.818).Subgroup analysis indicated that for patients during non-window period(≥48 h)with medium-grade fever(38.1℃-39℃),the XID+oseltamivir combination therapy reduced time to defervescence(P=0.04995/0.004)with a higher defervescence possibility(HR=1.524/1.683).Meanwhile,there’s no statistical significance but observable trends of the XID+oseltamivir group in the lower medical costs(3068.07 yuan vs 3120.68 yuan),the lower neutrophils%(48.53%vs 51.00%)and the higher lymphocyte%(39.83%vs 37.72%).Conclusion:The combination of XID and oseltamivir can shorten the time to defervescence and length of stay in influenza A.Its antipyretic effect is mainly reflected in the medium-grade and non-window periods.

The Role of Family Migration in Child Development:A Propensity Score Matching Analysis Based on Migrant and Non-Migrant Infants and Young Children

Based on the survey data of 4,739 infants and young children(IYC)under 3 years old,the study uses the propensity score matching(PSM)method to examine the role of family migration in infant and young child development(IYCD).The study finds that the development of migrant IYC is significantly behind that of non-migrant IYC in the real-world situation.After controlling for confounders at the individual and family levels,there is no significant statistical difference in early development between migrant IYC and non-migrant IYC.Moreover,family migration does not play a significant role in IYCD in different subgroups after PSM.To protect the rights of migrant families and IYC in accessing public services,the Chinese government should build a social security policy system for migrant families and ensure starting point fairness for migrant IYC.

Evaluation of early liquid drinking after radical gastrectomy in gastric cancer:a Chinese multicenter propensity score matching analysis

Background:Enhanced recovery after surgery is used in gastrointestinal surgery.This study aimed to access the effects of early liquid drinking(ELD)on gastrointestinal function recovery in patients with gastric cancer(GC)who underwent radical gastrectomy,as high-quality evidence on the outcomes of ELD after gastrectomy is currently lacking.Methods:Clinicopathological data of patients with GC from 11 centers were retrospectively analysed.Clinical outcomes were investigated in 555 patients,including 225 who started drinking liquid within 48 h(ELD group)of surgery and 330 who started drinking liquid after flatus resumption(traditional liquid drinking[TLD]group).Propensity score matching(PSM)analysis was performed using a match ratio of 1:1 and 201 patients were selected from each group for the analysis.Primary outcome was time to first passage of flatus.Secondary outcomes included time to first defecation,post-operative hospitalization days,occurrence of short-term post-operative complications,and hospitalization costs.Results:After PSM,baseline characteristics were not significantly different between the two groups.The time to first flatus(2.7261.08 vs 3.3661.39 days),first defecation(4.3461.85 vs 4.7761.61 days),and post-operative hospital stay(8.2764.02 vs 12.9464.43 days)were shorter in the ELD group than in the TLD group(all P<0.05).The ELD group had lower hospitalization costs than the TLD group([7.8362.44 vs 8.7863.41]104 RMB,P=0.041).No significant differences were observed in the incidence of post-operative complications.Conclusions:Compared with TLD,post-operative ELD could promote rapid recovery of gastrointestinal function and reduce hospitalization costs;moreover,ELD does not increase the risk of post-operative complications.

Routine nasogastric tube placement in patients with small esophageal perforation after endoscopic foreign body removal may be unnecessary:a propensity score matching analysis

Background:Nasogastric tube(NGT)placement is part of the post-operative management of upper gastrointestinal perforation,but its routine use in esophageal perforation(EP)caused by foreign bodies remains unclear.The purpose of this research was to investigate the necessity for routine NGT placement in patients with EP after endoscopic foreign body removal.Methods:A total of 323 patients diagnosed with EP caused by foreign bodies at the First Affiliated Hospital of Nanchang University between January 2012 and December 2021 were included in this retrospective study.Patients were divided into the NGT group and the non-NGT group according to whether or not NGT placement was performed.The perforation healing rate,post-operative adverse events,hospital stay,and death rate were analysed using a 1:1 propensity score matching model.Results:Before matching,there were 263 patients in the NGT group and 60 patients in the non-NGT group.There were significant differences in the time to treatment,infection,albumin,and types of endoscopy between the two groups,while the length of hospital stay in the NGT group was significantly longer than that in the non-NGT group.After 1:1 propensity score matching,48 pairs of patients were matched between the two groups.The perforation healing rate,post-operative adverse events,length of hospital stay,and death rate did not show significant differences between the two groups.Conclusions:For patients with small EP caused by foreign bodies,routine NGT placement after endoscopic foreign body removal may be unnecessary.