Constructing a Control Group Using Multivariate Matched Sampling Methods That Incorporate the Propensity Score

OBJECTIVESurgical site infection (SSI) after posterior spinal surgery is one of the severe complications that may occur despite administration of prophylactic antibiotics and the use of intraoperative aseptic precautions. The use of intrawound vancomycin powder for SSI prevention is still controversial, with a lack of high-quality and large-scale studies. The purpose of this retrospective study using a propensity score–matched analysis was to clarify whether intrawound vancomycin powder prevents SSI occurrence after spinal surgery.METHODSThe authors analyzed 1261 adult patients who underwent posterior spinal surgery between 2010 and 2018 (mean age 62.3 years; 506 men, 755 women; follow-up period at least 1 year). Baseline and surgical data were assessed. After a preliminary analysis, a propensity score model was established with adjustments for age, sex, type of disease, and previously reported risk factors for SSI. The SSI rates were compared between patients with intrawound vancomycin powder treatment (vancomycin group) and those without (control group).RESULTSIn a preliminary analysis of 1261 unmatched patients (623 patients in the vancomycin group and 638 patients in the control group), there were significant differences between the groups in age (p = 0.041), body mass index (p = 0.013), American Society of Anesthesiologists classification (p < 0.001), malnutrition (p = 0.001), revision status (p < 0.001), use of steroids (p = 0.019), use of anticoagulation (p = 0.033), length of surgery (p = 0.003), estimated blood loss (p < 0.001), and use of instrumentation (p < 0.001). There was no significant difference in SSI rates between the vancomycin and control groups (21 SSIs [3.4%] vs 33 SSIs [5.2%]; OR 0.640, 95% CI 0.368–1.111; p = 0.114). Using a one-to-one propensity score–matched analysis, 444 pairs of patients from the vancomycin and control groups were selected. There was no significant difference in the baseline and surgical data, except for height (p = 0.046), between both groups. The C-statistic for the propensity score model was 0.702. In the score-matched analysis, 12 (2.7%) and 24 (5.4%) patients in the vancomycin and control groups, respectively, developed SSIs (OR 0.486, 95% CI 0.243–0.972; p = 0.041). There were no systemic complications related to the use of vancomycin.CONCLUSIONSThe current study showed that intrawound vancomycin powder was useful in reducing the risk of SSI after posterior spinal surgery by half, without adverse events. Intrawound vancomycin powder use is a safe and effective procedure for SSI prevention.

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Effects of Polymyxin B Hemoperfusion on Septic Shock Patients Requiring Noradrenaline: Analysis of a Nationwide Administrative Database in Japan

Blood Purification ◽

10.1159/000513213 ◽

2021 ◽

pp. 1-6

Author(s):

Kenji Fujimori ◽

Kunio Tarasawa ◽

Kiyohide Fushimi

Keyword(s):

Septic Shock ◽

Propensity Score ◽

Propensity Score Matching ◽

Polymyxin B ◽

Administrative Database ◽

Control Group ◽

Continuous Hemodiafiltration ◽

Significant Survival ◽

Maximum Daily Dose ◽

Polymyxin B Hemoperfusion

Introduction: Polymyxin B hemoperfusion (PMX) reduces endotoxin in septic shock patients’ blood and can improve hemodynamics and organ functions. However, its effects on the reduction of septic shock mortality are controversial. Methods: Using the Japanese diagnosis procedure combination database from April 2016 to March 2019, we identified adult septic shock patients treated with noradrenaline. This study used propensity score matching to compare the outcome between PMX-treated and non-treated patients. The primary endpoint was 28-day mortality, counting from the day of noradrenaline initiation. The secondary endpoints were noradrenaline-, ventilator-, and continuous hemodiafiltration (CHDF)-free days at day 28. Results: Of 30,731 eligible patients, 4,766 received PMX. Propensity score matching produced a matched cohort of 4,141 pairs with well-balanced patient backgrounds. The 28-day survival rate was 77.9% in the PMX group and 71.1% in the control group (p < 0.0001). Median days of noradrenalin-, CHDF-, and ventilator-free days were 2 days (p < 0.0001), 2 days (p < 0.0001), and 6 days (p < 0.0001) longer in the PMX group than in the control group, respectively. When stratified with the maximum daily dose of noradrenaline, the PMX group showed a statistically significant survival benefit in the groups with noradrenaline dose <20 mg/day but not in the noradrenaline group dose ≥20 mg/day. Conclusion: Analysis of large Japanese databases showed that septic shock patients who received noradrenaline might benefit from PMX treatment.

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Placenta previa with posterior extrauterine adhesion: clinical features and management practice

BMC Surgery ◽

10.1186/s12893-020-01027-9 ◽

2021 ◽

Vol 21 (1) ◽

Author(s):

Yoshikazu Nagase ◽

Shinya Matsuzaki ◽

Masayuki Endo ◽

Takeya Hara ◽

Aiko Okada ◽

...

Keyword(s):

Propensity Score ◽

Blood Loss ◽

Cesarean Delivery ◽

Clinical Features ◽

Surgical Outcomes ◽

Multivariate Regression ◽

Placenta Previa ◽

Control Group ◽

Intraoperative Blood Loss ◽

Intraoperative Bleeding

Abstract Background A diagnostic sign on magnetic resonance imaging, suggestive of posterior extrauterine adhesion (PEUA), was identified in patients with placenta previa. However, the clinical features or surgical outcomes of patients with placenta previa and PEUA are unclear. Our study aimed to investigate the clinical characteristics of placenta previa with PEUA and determine whether an altered management strategy improved surgical outcomes. Methods This single institution retrospective study examined patients with placenta previa who underwent cesarean delivery between 2014 and 2019. In June 2017, we recognized that PEUA was associated with increased intraoperative bleeding; thus, we altered the management of patients with placenta previa and PEUA. To assess the relationship between changes in practice and surgical outcomes, a quasi-experimental method was used to examine the difference-in-difference before (pre group) and after (post group) the changes. Surgical management was modified as follows: (i) minimization of uterine exteriorization and adhesion detachment during cesarean delivery and (ii) use of Nelaton catheters for guiding cervical passage during Bakri balloon insertion. To account for patient characteristics, propensity score matching and multivariate regression analyses were performed. Results The study cohort (n = 141) comprised of 24 patients with placenta previa and PEUA (PEUA group) and 117 non-PEUA patients (control group). The PEUA patients were further categorized into the pre (n = 12) and post groups (n = 12) based on the changes in surgical management. Total placenta previa and posterior placentas were more likely in the PEUA group than in the control group (66.7% versus 42.7% [P = 0.04] and 95.8% versus 63.2% [P < 0.01], respectively). After propensity score matching (n = 72), intraoperative blood loss was significantly higher in the PEUA group (n = 24) than in the control group (n = 48) (1515 mL versus 870 mL, P < 0.01). Multivariate regression analysis revealed that PEUA was a significant risk factor for intraoperative bleeding before changes were implemented in practice (t = 2.46, P = 0.02). Intraoperative blood loss in the post group was successfully reduced, as opposed to in the pre group (1180 mL versus 1827 mL, P = 0.04). Conclusions PEUA was associated with total placenta previa, posterior placenta, and increased intraoperative bleeding in patients with placenta previa. Our altered management could reduce the intraoperative blood loss.

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Allogenic Pure Platelet-Rich Plasma Therapy for Adhesive Capsulitis: A Bed-to-Bench Study With Propensity Score Matching Using a Corticosteroid Control Group

The American Journal of Sports Medicine ◽

10.1177/03635465211018636 ◽

2021 ◽

pp. 036354652110186

Author(s):

Min Ji Lee ◽

Kang Sup Yoon ◽

Sohee Oh ◽

Sue Shin ◽

Chris Hyunchul Jo

Keyword(s):

Muscle Strength ◽

Propensity Score ◽

Inflammatory Cytokines ◽

Platelet Rich Plasma ◽

Corticosteroid Injection ◽

Adhesive Capsulitis ◽

Shoulder Function ◽

Control Group ◽

Inflammatory Condition

Background: While platelet-rich plasma (PRP) has been widely studied for musculoskeletal disorders, few studies to date have reported its use for adhesive capsulitis (AC). Fully characterized and standardized allogenic PRP may provide clues to solve the underlying mechanism of PRP with respect to synovial inflammation and thus may clarify its clinical indications. Purpose: To clinically evaluate the safety and efficacy of a fully characterized pure PRP injection in patients with AC and to assess the effects of pure PRP on synoviocytes with or without inflammation in vitro. Study Design: Controlled laboratory study and cohort study; Level of evidence, 3. Methods: For the clinical analysis, a total of 15 patients with AC received an ultrasonography-guided intra-articular PRP injection and were observed for 6 months. Pain, range of motion (ROM), muscle strength, shoulder function, and overall satisfaction in the patients were evaluated using questionnaires at 1 week as well as at 1, 3, and 6 months after the PRP injection and results were compared with the results of a propensity score−matched control group that received a corticosteroid injection (40 mg triamcinolone acetonide). For the in vitro analysis, synoviocytes were cultured with or without interleukin-1β (IL-1β) and PRP. The gene expression of proinflammatory and anti-inflammatory cytokines as well as matrix enzymes and their inhibitors was evaluated. Results: At 6-month follow-up, pure PRP significantly decreased pain and improved ROM, muscle strength, and shoulder function to levels comparable with those after a corticosteroid injection. All pain values, strength measurements, and functional scores significantly improved up to 6 months in the PRP group, but these measures improved up to 3 months and then were decreased at 6 months in the corticosteroid group. ROM was significantly improved in the 2 groups at 6 months compared with baseline. Allogenic PRP did not cause adverse events. For the in vitro findings, PRP induced inflammation but significantly improved the IL 1β−induced synovial inflammatory condition by decreasing proinflammatory cytokines such as IL-1β, tumor necrosis factor−α, IL-6, cyclooxygenase-2, and microsomal prostaglandin E synthase−1 and decreased matrix enzymes (matrix metalloproteinase−1, −3, and −13 as well as a disintegrin and metalloproteinase with thrombospondin motifs−4 and −5) and further increasing anti-inflammatory cytokines such as vasoactive intestinal peptide. Conclusion: This study showed that PRP decreased pain and improved shoulder ROM and function to an extent comparable with that of a corticosteroid in patients with AC. Allogenic pure PRP acted in a pleiotropic manner and decreased proinflammatory cytokines only in the inflammatory condition. Clinical Relevance: Allogenic PRP could be a treatment option for the inflammatory stage of AC.

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Outcomes of Incisional Hernia Repair Surgery After Multiple Re-recurrences: A Propensity Score Matched Analysis

World Journal of Surgery ◽

10.1007/s00268-021-05952-5 ◽

2021 ◽

Author(s):

Dimitri Sneiders ◽

Gijs H. J. de Smet ◽

Floris den Hartog ◽

Yagmur Yurtkap ◽

Anand G. Menon ◽

...

Keyword(s):

Propensity Score ◽

Incisional Hernia ◽

Incisional Hernia Repair ◽

Recurrent Hernia ◽

Control Group ◽

Baseline Characteristics ◽

Biological Situation ◽

Similar Risk

Abstract Background Patients with a re-recurrent hernia may account for up to 20% of all incisional hernia (IH) patients. IH repair in this population may be complex due to an altered anatomical and biological situation as a result of previous procedures and outcomes of IH repair in this population have not been thoroughly assessed. This study aims to assess outcomes of IH repair by dedicated hernia surgeons in patients who have already had two or more re-recurrences. Methods A propensity score matched analysis was performed using a registry-based, prospective cohort. Patients who underwent IH repair after ≥ 2 re-recurrences operated between 2011 and 2018 and who fulfilled 1 year follow-up visit were included. Patients with similar follow-up who underwent primary IH repair were propensity score matched (1:3) and served as control group. Patient baseline characteristics, surgical and functional outcomes were analyzed and compared between both groups. Results Seventy-three patients operated on after ≥ 2 IH re-recurrences were matched to 219 patients undergoing primary IH repair. After propensity score matching, no significant differences in patient baseline characteristics were present between groups. The incidence of re-recurrence was similar between groups (≥ 2 re-recurrences: 25% versus control 24%, p = 0.811). The incidence of complications, as well as long-term pain, was similar between both groups. Conclusion IH repair in patients who have experienced multiple re-recurrences results in outcomes comparable to patients operated for a primary IH with a similar risk profile. Further surgery in patients who have already experienced multiple hernia re-recurrences is justifiable when performed by a dedicated hernia surgeon.

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Effects of Acupuncture on Lowering Blood Pressure in Postmenopausal Women with Prehypertension or Stage 1 Hypertension: A Propensity Score-Matched Analysis

Journal of Clinical Medicine ◽

10.3390/jcm10071426 ◽

2021 ◽

Vol 10 (7) ◽

pp. 1426

Author(s):

Bok-Nam Seo ◽

Ojin Kwon ◽

Siwoo Lee ◽

Ho-Seok Kim ◽

Kyung-Won Kang ◽

...

Keyword(s):

Blood Pressure ◽

Cardiovascular Diseases ◽

Propensity Score ◽

Systolic Blood Pressure ◽

Diastolic Blood Pressure ◽

Postmenopausal Women ◽

Analysis Of Covariance ◽

Control Group ◽

Matched Design ◽

Stage 1

Postmenopausal women have a higher prevalence of hypertension compared to premenopausal women. Hypertension is a risk factor for cardiovascular diseases, the prevalence of which is ever increasing. This study investigated the effects of long-term acupuncture on lowering the blood pressure of postmenopausal women with prehypertension and stage 1 hypertension. Participants were 122 postmenopausal women aged less than 65 years, diagnosed with prehypertension or stage 1 hypertension (systolic blood pressure 120–159 mmHg or diastolic blood pressure 80–99 mmHg). We used a propensity score-matched design. The experimental group (n = 61) received acupuncture for four weeks every six months over a period of two years. The control group (n = 61) received no intervention. An Analysis of covariance (ANCOVA) was performed for the primary efficacy analysis. Relative risk ratios were used to compare group differences in treatment effects. Acupuncture significantly reduced the participants’ diastolic blood pressure (−9.92 mmHg; p < 0.001) and systolic blood pressure (−10.34 mmHg; p < 0.001) from baseline to follow-up. The results indicate that acupuncture alleviates hypertension in postmenopausal women, reducing their risk of developing cardiovascular diseases and improving their health and quality of life.

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Bicyclol for the treatment of drug-induced liver injury: a propensity score matching analysis using a nationwide inpatient database

Journal of International Medical Research ◽

10.1177/03000605211005945 ◽

2021 ◽

Vol 49 (4) ◽

pp. 030006052110059

Author(s):

Yongfeng Wang ◽

Rongtao Lai ◽

Peilan Zong ◽

Qingling Xu ◽

Jia Shang ◽

...

Keyword(s):

Liver Injury ◽

Propensity Score ◽

Propensity Score Matching ◽

Statistical Significance ◽

Control Group ◽

Time Interval ◽

Potential Candidate ◽

Drug Induced ◽

Drug Induced Liver Injury ◽

Propensity Score Matching Analysis

ObjectiveTo evaluate the efficacy and safety of bicyclol in patients with drug-induced liver injury (DILI) using a nationwide database.MethodsWe retrospectively analyzed the clinical data of DILI patients in the DILI-R database. Propensity score matching was performed to balance the bicyclol and control groups, and alanine aminotransferase (ALT) recovery was compared between the two groups. Factors associated with ALT recovery and safety were identified.ResultsThe analysis included the data of 25,927 patients. Eighty-seven cases were included in the bicyclol group, with 932 cases in the control group. One-to-one propensity score matching created 86 matched pairs. The ALT normalization rate in the bicyclol group was significantly higher than that in the control group (50.00% vs. 24.42%), and statistical significance was found in the superiority test. After adjustment of baseline ALT levels, baseline total bilirubin levels, sex, age, acute or chronic liver diseases, and suspected drugs in the multivariate logic regression analysis, the major influencing factors for ALT recovery included the time interval between ALT tests (days) and the group factor (bicyclol treatment). There were no differences in the proportion of renal function impairment or blood abnormalities between the two groups.ConclusionsBicyclol is a potential candidate for DILI.

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Abstract 14301: Effects of Septal Reduction Therapy on Acute Cardiovascular Events and All-cause Mortality in Patients With Obstructive Hypertrophic Cardiomyopathy: Propensity Score-matched Study

Circulation ◽

10.1161/circ.142.suppl_3.14301 ◽

2020 ◽

Vol 142 (Suppl_3) ◽

Author(s):

Sae Morita ◽

Yanling Zhao ◽

Kohei Hasegawa ◽

Muredach P Reilly ◽

Mathew S Maurer ◽

...

Keyword(s):

Hypertrophic Cardiomyopathy ◽

Propensity Score ◽

New York State ◽

Control Group ◽

Short Term ◽

Alcohol Septal Ablation ◽

Septal Myectomy ◽

All Cause Mortality ◽

Obstructive Hypertrophic Cardiomyopathy ◽

Matched Study

Introduction: Septal reduction therapy (SRT) - i.e., septal myectomy and alcohol septal ablation - has been used to treat medically-refractory obstructive hypertrophic cardiomyopathy (HOCM) for a few decades. However, the effects of SRT on the risk of acute cardiovascular (CV) events and all-cause mortality are largely unknown. Hypothesis: SRT is associated with a long-term decrease in acute CV events and a short-term increase in all-cause mortality in patients with HOCM. Methods: We performed a propensity score (PS)-matched study using all-payer databases that capture all hospitalizations and outpatient visits in New York State. We identified patients with HOCM who underwent SRT between January 1, 2007 and December 31, 2014 (i.e., the SRT group) and those who have never had SRT but had at least one hospitalization for HOCM during the same period (i.e., the control group). We performed 1:1 PS matching using age, sex, race/ethnicity, source of payment, season and year of starting event follow-up (i.e., the day of SRT or the index hospitalization), and Elixhauser comorbidity measures. The primary outcomes were (1) acute CV event (i.e., emergency department visit or unplanned hospitalization for CV disease) during 1-360 days and 361-720 days and (2) 7-, 15-, 30-, 180-, and 360-day all-cause mortality. We compared the risk of the outcome event using logistic regression models. Results: The analytic cohort consisted of 690 patients with HOCM (i.e., 345 PS-matched pairs). The SRT group had a lower risk of acute CV event during 361-720 days (OR 0.44; 95% CI, 0.20-0.97; P=0.04) but a higher risk of 7-day mortality (11 vs. 2 in the control group; P=0.03). The SRT group had a non-significant trend towards lower all-cause mortality in longer terms ( Figure ). Conclusion: In this population-based PS-matched study of patients with HOCM, SRT was associated with a reduced risk of acute CV events in the second post-procedure year at the sacrifice of a short-term increase in all-cause mortality.

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