BACKGROUND: Comparative studies on surgical treatments with time-to-event endpoints have provided substantial evidence for clinical practice, but the accurate use of survival data analysis and the control of confounding bias remain big challenges.
METHODS: This was a survey of surgical studies with survival outcomes published in four general medical journals and five general surgical journals in 2021. The two most concerned statistical issues were evaluated, including confounding control by propensity score analysis (PSA) or multivariable analysis and testing of proportional hazards (PH) assumption in Cox model.
RESULTS: A total of 74 studies were included, comprising 63 observational studies and 11 randomized controlled trials. Among the observational studies, the proportion of studies utilizing PSA in surgical oncology and non-oncology studies was similar (40.9 % versus 36.8 %, P = 0.762). However, the former reported a significantly lower proportion of PH assumption assessments compared to the latter (13.6 % versus 42.1 %, P = 0.020). Twenty-five observational studies (25/63) used PSA methods, but two-thirds of them (17/25) showed unclear balance of baseline data after PSA. And the proportion of PH assumption testing after PSA was slightly lower than that before PSA, but the difference was not statistically significant (24.0 % versus 28.0 %, P = 0.317). Comprehensive suggestions were given on confounding control in survival analysis and alternative resolutions for non-compliance with PH assumption.
CONCLUSIONS: This study highlights suboptimal reporting of PH assumption evaluation in observational surgical studies both before and after PSA. Efforts and consensus are needed with respect to the underlying assumptions of statistical methods.

In epidemiology and social sciences, propensity score methods are popular for estimating treatment effects using observational data, and multiple imputation is popular for handling covariate missingness. However, how to appropriately use multiple imputation for propensity score analysis is not completely clear. This paper aims to bring clarity on the consistency (or lack thereof) of methods that have been proposed, focusing on the within approach (where the effect is estimated separately in each imputed dataset and then the multiple estimates are combined) and the across approach (where typically propensity scores are averaged across imputed datasets before being used for effect estimation). We show that the within method is valid and can be used with any causal effect estimator that is consistent in the full-data setting. Existing across methods are inconsistent, but a different across method that averages the inverse probability weights across imputed datasets is consistent for propensity score weighting. We also comment on methods that rely on imputing a function of the missing covariate rather than the covariate itself, including imputation of the propensity score and of the probability weight. Based on consistency results and practical flexibility, we recommend generally using the standard within method. Throughout, we provide intuition to make the results meaningful to the broad audience of applied researchers.

UNASSIGNED: The optimal regimen of infliximab salvage in acute severe ulcerative colitis (ASUC) patients remains controversial. This study aimed to compare accelerated and standard infliximab induction in Chinese ASUC patients, and to explore risk factors and concrete accelerated regimens for them.
UNASSIGNED: Data were retrospectively collected from steroid-refractory ASUC patients receiving infliximab as rescue therapy at seven tertiary centers across China. Outcomes including colectomy and clinical remission (Mayo score ≤ 2 and every subscore ≤ 1 at Day 14) rates were compared between patients receiving accelerated and standard infliximab induction using propensity score adjustment for potential confounders. The dose-response relationship was explored by plotting restricted cubic splines. Logistic regression and Cox proportional hazards regression analyses were performed to determine risk factors for adverse outcomes. A systematic review and meta-analysis was also performed.
UNASSIGNED: A total of 76 patients were analysed: 29 received standard and 47 received accelerated induction. The accelerated group had a higher 90-day colectomy rate (17.8% vs 0%, P = 0.019) and lower clinical remission rate (27.7% vs 65.5%, P = 0.001). After adjusting for propensity score and institution, there was no significant difference in colectomy or clinical remission rates (both P > 0.05). Dose-effect curves showed decreased colectomy hazard with higher cumulative infliximab dosage within 5 days, with no improvement observed for increasing cumulative infliximab dosage within 28 days. Multivariate logistic regression analyses revealed C-reactive protein of >10 mg/L at infliximab initiation (odds ratio = 5.00, 95% confidence interval: 1.27-24.34) as an independent risk factor for no clinical remission. Meta-analysis also revealed no significant difference in colectomy rates at 3 months (P = 0.54).
UNASSIGNED: After adjusting for confounders, there were no significant differences in colectomy or clinical remission rates between accelerated and standard infliximab induction among ASUC patients. Early administration of an intensified dosage within 5 days may be beneficial. Elevated C-reactive protein at infliximab initiation indicated need for intensive treatment.

BACKGROUND: We investigated the real-world efficacy of adjuvant therapy for stage I lung adenocarcinoma patients with pathological high-risk factors.
METHODS: Study participants were enrolled from November 1, 2016 and December 31, 2020. Clinical bias was balanced by propensity score matching. Disease-free survival (DFS) outcomes were compared by Kaplan-Meier analysis. The Cox proportional hazards regression was used to identify survival-associated factors. p ≤ 0.05 was the threshold for statistical significance.
RESULTS: A total of 454 patients, among whom 134 (29.5%) underwent adjuvant therapy, were enrolled in this study. One hundred and eighteen of the patients who underwent adjuvant therapy were well matched with non-treatment patients. Prognostic outcomes of the treatment group were significantly better than those of the non-treatment group, as revealed by Kaplan-Meier analysis after PSM. Differences in prevention of recurrence or metastasis between the targeted therapy and chemotherapy groups were insignificant. Adjuvant therapy was found to be positive prognostic factors, tumor size and solid growth patterns were negative.
CONCLUSIONS: Adjuvant therapy significantly improved the DFS for stage I lung adenocarcinoma patients with high-risk factors. Larger prospective clinical trials should be performed to verify our findings.

BACKGROUND: Whether adjuvant chemotherapy should be different for patients with stage II and III gastric cancer is unknown.
METHODS: We retrospectively analyzed the effects of adjuvant chemotherapy on the outcomes of 140 and 256 patients with stage II and III gastric cancer, respectively, between January 2008 and December 2018. Chemotherapies were stratified as fluoropyrimidine plus platinum versus fluoropyrimidine alone, tegafur/gimeracil/octeracil (S-1)-containing versus non-S-1-containing regimens, and S-1 plus cisplatin versus S-1 alone.
RESULTS: The median age of patients was 67.0 (range 24.6-98.8) years. With a median follow-up of 105 months, recurrence occurred in 32 (22.9%) and 130 (50.8%) patients with stage II and III disease, respectively. Adjuvant chemotherapy was administered as fluoropyrimidine monotherapy to 68 (48.6%) and 73 (28.5%) patients, fluoropyrimidine plus platinum to 9 (6.4%) and 104 (40.6%) patients, and none to 63 (45.0%) and 79 (30.9%) patients with stage II and III gastric cancer, respectively. Doublet chemotherapy was associated with longer disease-free survival (DFS) (26.5 vs. 15.2 months, P = 0.001) and overall survival (OS) (41.2 vs. 22.0 months, P < 0.001) than fluoropyrimidine monotherapy for stage IIIB-IIIC disease. Furthermore, S-1-containing regimens prolonged DFS (57.4 vs. 21.9 months, P = 0.044) and OS (81.4 vs. 28.6 months, P = 0.023) compared with non-S-1-containing chemotherapy in stage III disease.
CONCLUSIONS: Although fluoropyrimidine monotherapy is feasible for stage II-IIIA disease, doublet chemotherapy is significantly associated with longer survival than monotherapy for stage IIIB-IIIC disease. S-1-containing regimens might lead to longer survival than non-S-1-containing chemotherapy in stage III gastric cancer.

The combination of propensity score analysis and multiple imputation has been prominent in epidemiological research in recent years. However, studies on the evaluation of balance in this combination are limited. In this paper, we propose a new method for assessing balance in propensity score analysis following multiple imputation. A simulation study was conducted to evaluate the performance of balance assessment methods (Leyrat\'s, Leite\'s, and new method). Simulated scenarios varied regarding the presence of missing data in the control or treatment and control group, and the imputation model with/without outcome. Leyrat\'s method was more biased in all the studied scenarios. Leite\'s method and the combine method yielded balanced results with lower mean absolute difference, regardless of whether the outcome was included in the imputation model or not. Leyrat\'s method had a higher false positive ratio and Leite\'s and combine method had higher specificity and accuracy, especially when the outcome was not included in the imputation model. According to simulation results, most of time, Leyrat\'s method and Leite\'s method contradict with each other on appraising the balance. This discrepancy can be solved using new combine method.

BACKGROUND: Carbapenem-resistant Enterobacteriaceae (CRE) infections pose a significant threat to global health due to limited treatment options and high mortality rates. Colistin-based regimens have emerged as a primary treatment approach, but the effectiveness and mortality outcomes of colistin monotherapy versus colistin-fosfomycin combination therapy remain uncertain. This study aims to compare the effectiveness and mortality of colistin monotherapy and colistin-fosfomycin combination therapy for CRE infections. Notably, our study is the first to undertake a comprehensive examination of the effectiveness and mortality outcomes between colistin monotherapy and colistin-fosfomycin combination therapy in the context of CRE infections.
METHODS: A retrospective cohort study was conducted using data from patients diagnosed with carbapenem-resistant Enterobacteriaceae (CRE) infections at Nakornping Hospital during 2015 to 2022. Inverse probability weighting (IPW) was employed to create balanced cohorts of patients receiving either colistin monotherapy or colistin-fosfomycin combination therapy. The primary outcome measure was treatment effectiveness, assessed by 30-day mortality. Secondary outcome measures included clinical response, mortality at the end of treatment, and microbiologic response. Univariate and multivariate logistic regression analysis were employed after applying propensity score weighting using inverse probability of weighting (IPW).
RESULTS: A total of 220 patients were included in the analysis, with 67 receiving colistin monotherapy and 153 receiving colistin-fosfomycin combination therapy. Propensity score weighting using IPW balanced the baseline characteristics between the two groups. The effectiveness of treatment, as measured by 30-day mortality, was not significantly different between the colistin monotherapy group and the colistin-fosfomycin combination therapy group (adjusted odds ratio [aOR] = 1.51, 95% confidence interval [CI]: 0.60-3.78, p = 0.383). Similarly, no significant difference was observed in the mortality at the end of treatment between the two groups (aOR = 1.26, 95% CI: 0.55-2.90, p = 0.576). The clinical response (aOR = 1.48, 95% CI: 0.61-3.59, p = 0.383) and microbiologic response (aOR = 0.66, 95% CI: 0.18-2.38, p = 0.527) were similar between the colistin monotherapy and colistin-fosfomycin combination therapy groups.
CONCLUSIONS: The propensity score analysis among 220 matched patients showed comparable treatment effectiveness and mortality between colistin monotherapy and colistin-fosfomycin combination therapy for CRE infections. These results suggest that colistin monotherapy may be as effective as combination therapy. More prospective randomized controlled trials are needed to confirm these findings and establish optimal CRE treatment strategies.

METHODS: Retrospective cohort study.
OBJECTIVE: With the aging of the Japanese population, patients with athetoid cerebral palsy (ACP) are getting older, and the rate of surgery for CSM is increasing in ACP patients. However, postoperative complications of such surgery among adult patients with ACP have not been reported yet. We investigated postoperative complications of surgery for CSM with ACP and compared them with those of surgery for CSM without ACP using a national inpatient database of Japan.
METHODS: Using the Diagnosis Procedure Combination database, we identified 61382 patients who underwent surgery for CSM from July 2010 to March 2018. We examined patient backgrounds, surgical procedures, and type of hospital, and a 4:1 propensity score matching was performed to compare the outcomes between the non-ACP and ACP groups.
RESULTS: There were 60 847 patients without ACP and 535 patients with ACP. The mean age was 68.5 years in the non-ACP group and 55 years in the ACP group. The percentages of patients who underwent fusion surgery were 21.6% and 68.8% in the non-ACP and ACP groups, respectively. The 4:1 propensity score matching selected 1858 in the non-ACP group and 465 in the ACP group. The ACP group was more likely to have postoperative urinary tract infection (.4% vs 2.8%, P < .001), postoperative pneumonia (.4% vs 2.4%, P < .001), and 90-day readmission for reoperation (1.9% vs 4.3%, P = .003).
CONCLUSIONS: We found that ACP patients were more vulnerable to postoperative complications and reoperation after CSM than non-ACP patients.

OBJECTIVE: To determine the influence of presenting electrocardiographic (ECG) changes on prognosis in acute coronary syndrome cardiogenic shock (ACS-CS) patients undergoing percutaneous coronary angiography (PCI).
BACKGROUND: The effect of initial ECG changes such as ST-elevation myocardial infarction (STEMI) versus non-STEMI among patients ACS-CS on prognosis remains unclear.
METHODS: We analysed data from consecutive patients with ACS-CS enrolled in the Victorian Cardiac Outcomes registry between 2014 and 2020. Inverse probability of treatment weighting analysis (IPTW) was used to assess the effect of ECG changes on 30-day mortality.
RESULTS: Of 1564 patients with ACS-CS who underwent PCI, 161 had non-STEMI and 1403 had STEMI on ECG. The mean age was 66 ± 13 years, and 74 % (1152) were males. Patients with non-STEMI compared to STEMI were older (70 ± 12 vs 65 ± 13 years), had higher rates of diabetes (34 % vs 21 %), prior coronary artery bypass graft surgery (14 % vs 3.3 %), peripheral arterial disease (10.6 % vs 4.1 %, p < 0.01), and lower baseline eGFR (53.8 [37.1, 75.4] vs 65.3 [46.3, 87.8] ml/min/1.73m2), all p ≤ 0.01. Non-STEMI patients were more likely to have a culprit left circumflex artery (29 % vs 20 %) and more often underwent multivessel percutaneous coronary intervention (30 % vs 20 %) but had lower rates of out-of-hospital cardiac arrest (21 % vs 39 %), all p ≤ 0.01. Propensity score analysis with IPTW confirmed that non-STEMI ECG was associated with lower odds for 30-day all-cause mortality (OR 0.47 [0.32, 0.69], p < 0.001), and 30-day major adverse cardiovascular and cerebrovascular events (OR 0.48 [0.33, 0.70]).
CONCLUSIONS: In patients undergoing PCI, Non-STEMI as compared to STEMI on index ECG was associated with approximately half the relative risk of both 30-day mortality and 30-day MACCE and could be a useful variable to integrate in ACS-CS risk scores.

UNASSIGNED: The causal relationship between undernutrition and response to anti-tuberculosis (TB) treatment and TB treatment outcomes among people with retreatment TB is understudied.
UNASSIGNED: To evaluate the effect of undernutrition on treatment success and sputum smear conversion among people with retreatment drug-susceptible TB in Kampala, Uganda.
UNASSIGNED: We conducted a quasi-experimental study utilizing propensity score weighting among people with retreatment drug-susceptible TB aged ≥ 15 years treated between 2012 and 2022 in Kampala. The primary exposure was undernutrition assessed using the mid-upper arm circumference at the time of TB diagnosis. The primary outcome was treatment success defined as cure or treatment completion at month 6. Sputum smear conversion was the secondary outcome and was measured as a change in sputum smear status from positive to negative at months 2, 5, and 6. We estimated the causal effect of undernutrition on the outcomes using a propensity-score weighted modified Poisson regression model with robust error variance.
UNASSIGNED: Of the 605 participants, 432 (71.4 %) were male, 215 (35.5 %) were aged 25-34 years, 427 (70.6 %) had bacteriologically confirmed pulmonary TB, 133 (22.0 %) were undernourished and 398 (65.8 %) achieved treatment success. Of participants with bacteriologically confirmed pulmonary TB, 232 (59.0 %), 327 (59.3 %), and 360 (97.6 %) achieved sputum smear conversion at months 2, 5, and 6, respectively. Undernutrition reduced treatment success (RR 0.42, 95 % CI 0.32-0.55) as well as sputum smear conversion at months 2 (RR 0.45, 95 % CI 0.42-0.49) and 5 (RR 0.46, 95 % CI 0.43-0.51) but not month 6 (RR 0.99, 95 % CI 0.97-1.02).
UNASSIGNED: Undernutrition negatively impacts treatment outcomes. Therefore, nutritional assessment should be an integral component of TB care, with nutritional counseling and support offered to those undernourished to optimize their TB treatment response and outcomes.