Hemmila MR, Birkmeyer NJ, Arbabi S, et al. Introduction to propensity scores: a case study on the comparative effectiveness of laparoscopic vs open appendectomy

Department of Surgery, University of Michigan Medical School, Ann Arbor, 48109-5033, USA.
Archives of surgery (Chicago, Ill.: 1960) (Impact Factor: 4.93). 10/2010; 145(10):939-45. DOI: 10.1001/archsurg.2010.193
Source: PubMed


To demonstrate the use of propensity scores to evaluate the comparative effectiveness of laparoscopic and open appendectomy.
Retrospective cohort study.
Academic and private hospitals.
All patients undergoing open or laparoscopic appendectomy (n = 21 475) in the Public Use File of the American College of Surgeons National Surgical Quality Improvement Program were included in the study. We first evaluated the surgical approach (laparoscopic vs open) using multivariate logistic regression. We next generated propensity scores and compared outcomes for open and laparoscopic appendectomy in a 1:1 matched cohort. Covariates in the model for propensity scores included comorbidities, age, sex, race, and evidence of perforation.
Patient morbidity and mortality, rate of return to operating room, and hospital length of stay.
Twenty-eight percent of patients underwent open appendectomy, and 72% had a laparoscopic approach; 33% (open) vs 14% (laparoscopic) had evidence of a ruptured appendix. In the propensity-matched cohort, there was no difference in mortality (0.3% vs 0.2%), reoperation (1.8% vs 1.5%), or incidence of major complications (5.9% vs 5.4%) between groups. Patients undergoing laparoscopic appendectomy experienced fewer wound infections (odds ratio [OR], 0.4; 95% confidence interval [CI], 0.3-0.5) and fewer episodes of sepsis (0.8; 0.6-1.0) but had a greater risk of intra-abdominal abscess (1.7; 1.3-2.2). An analysis using multivariate adjustment resulted in similar findings.
After accounting for patient severity, open and laparoscopic appendectomy had similar clinical outcomes. In this case study, propensity score methods and multivariate adjustment yielded nearly identical results.

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    • "For the secondary analysis we will develop a propensity score model as published before [43,44]. Characteristics including fracture type, age, gender, mechanism of injury, dominance, and activity levels will be included in this model; the resulting propensity score represents the chance of being operated. "
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    ABSTRACT: Fractures of the humeral shaft are associated with a profound temporary (and in the elderly sometimes even permanent) impairment of independence and quality of life. These fractures can be treated operatively or non-operatively, but the optimal tailored treatment is an unresolved problem. As no high-quality comparative randomized or observational studies are available, a recent Cochrane review concluded there is no evidence of sufficient scientific quality available to inform the decision to operate or not. Since randomized controlled trials for this injury have shown feasibility issues, this study is designed to provide the best achievable evidence to answer this unresolved problem. The primary aim of this study is to evaluate functional recovery after operative versus non-operative treatment in adult patients who sustained a humeral shaft fracture. Secondary aims include the effect of treatment on pain, complications, generic health-related quality of life, time to resumption of activities of daily living and work, and cost-effectiveness. The main hypothesis is that operative treatment will result in faster recovery.Methods/design: The design of the study will be a multicenter prospective observational study of 400 patients who have sustained a humeral shaft fracture, AO type 12A or 12B. Treatment decision (i.e., operative or non-operative) will be left to the discretion of the treating surgeon. Critical elements of treatment will be registered and outcome will be monitored at regular intervals over the subsequent 12 months. The primary outcome measure is the Disabilities of the Arm, Shoulder, and Hand score. Secondary outcome measures are the Constant score, pain level at both sides, range of motion of the elbow and shoulder joint at both sides, radiographic healing, rate of complications and (secondary) interventions, health-related quality of life (Short-Form 36 and EuroQol-5D), time to resumption of ADL/work, and cost-effectiveness. Data will be analyzed using univariate and multivariable analyses (including mixed effects regression analysis). The cost-effectiveness analysis will be performed from a societal perspective. Successful completion of this trial will provide evidence on the effectiveness of operative versus non-operative treatment of patients with a humeral shaft fracture.Trial registration: The trial is registered at the Netherlands Trial Register (NTR3617).
    Full-text · Article · Feb 2014 · BMC Musculoskeletal Disorders
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    ABSTRACT: Appendicitis is the most common surgical emergency with the incidence rate of 6-10%. Although several studies have compared the two approaches of open (OA) and laparoscopic appendectomy (LA) the technique of choice is still a matter of controversy. Considering this background we designed a study to compare OA and LA outcomes in our center. One hundred patients were included in this study performed from April 2008 to April 2009 at Shahid Sadoughi hospital, Yazd, Iran. Patients who gave informed consent were randomized to either OA or LA groups and were operated by McBurney's or laparoscopic technique, respectively. Patients received our center's routine diet, antibiotics and analgesic regimens. The patients' pain was measured by visual analogue scale (VAS) at their entrance to the recovery room and in 6-hour intervals up to 24 hours. Post-operation follow up visits were in weeks 1, 2 and 4. The data of operation time, hospital stay, intra-operation complications, time to resume normal activity, short term complications and neuralgia were collected and analysed. The average operation time was 34.4±8.42 min in LA and 41.7±8.84 in OA hand (P=0001). No intra-operative complication and no LA to OA conversion were encountered in operations. Post-operative complication rate was higher in OA group (n=10) compared to LA (n=3). The post-operative pain showed less pain in OA only at 6 and 12 hours post-operative times. Patients' mean hospital stay was 52.32±19.2 and 42.96±13.8 hours in LA and OA groups, respectively (P=0.003). Time to resume normal activity didn't show a significant difference between two groups (P=0.53). Only one case of neuralgia in the OA group was confronted in the follow up visits. LA has less complications and cosmetic scar with the cost of more pain. Decision between OA and LA for each patient should be made individually.
    Full-text · Article · Jun 2011 · Acta medica Iranica
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