Introduction to propensity scores: A case study on the comparative effectiveness of laparoscopic vs open appendectomy
ABSTRACT 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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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.Acta medica Iranica 06/2011; 49(6):352-6.
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ABSTRACT: Recent reports indicate that mortality after trauma center admission may be directly related to the rate of operative intervention after blunt solid organ injury. These findings bring into question the role of urgent splenectomy after blunt splenic injury (BSI). The purpose of this study was to determine the role of urgent splenectomy (defined as splenectomy within 6 hours of admission) in the management of BSI as well as the relationship between urgent splenectomy and in-hospital mortality. The National Trauma Data Bank for 2007 was queried for adults (18-81) who suffered BSI. Patients who died in or were transferred from the emergency department were excluded. Hierarchical multivariate models were used to account for clustering of patients within hospitals and to identify hospital and patient factors associated with urgent splenectomy. Propensity score matching was used to analyze the relationship between urgent splenectomy and mortality. There were 507,202 total incidents identified. Of those, 11,793 met inclusion criteria. Urgent splenectomy was performed on 1,104 (9.4%). Hierarchical models revealed that age ≥55 years, arrival systolic blood pressure ≤90 mm Hg, no or mild head injury, increasing injury severity, and massive disruption of the spleen were associated with urgent splenectomy. Hospitals level factors associated with urgent splenectomy included hospital region, hospital type, and trauma center level. The propensity-matched cohorts revealed no association between urgent splenectomy and in-hospital mortality (odds ratio, 1.08; 95% confidence interval, 0.82-1.42). Despite ongoing variation in the use of urgent splenectomy after BSI in adults, urgent splenectomy was not associated with in-hospital mortality.The Journal of trauma 07/2011; 71(5):1333-9. DOI:10.1097/TA.0b013e318224d0e4 · 2.96 Impact Factor