The DEcIDE Methods Center publishes a monthly literature scan of current articles of interest to the field of comparative effectiveness research.

You can find them all here.

September 2011


CER Scan [Epub ahead of print]


    1. Biostatistics. 2011 Aug 18. [Epub ahead of print]

    A robust method using propensity score stratification for correcting verification bias for binary tests. He H, McDermott MP. Department of Biostatistics and Computational Biology, University of Rochester, Rochester, NY 14642, USA.

    Sensitivity and specificity are common measures of the accuracy of a diagnostic test. The usual estimators of these quantities are unbiased if data on the diagnostic test result and the true disease status are obtained from all subjects in an appropriately selected sample. In some studies, verification of the true disease status is performed only for a subset of subjects, possibly depending on the result of the diagnostic test and other characteristics of the subjects. Estimators of sensitivity and specificity based on this subset of subjects are typically biased; this is known as verification bias. Methods have been proposed to correct verification bias under the assumption that the missing data on disease status are missing at random (MAR), that is, the probability of missingness depends on the true (missing) disease status only through the test result and observed covariate information. When some of the covariates are continuous, or the number of covariates is relatively large, the existing methods require parametric models for the probability of disease or the probability of verification (given the test result and covariates), and hence are subject to model misspecification. We propose a new method for correcting verification bias based on the propensity score, defined as the predicted probability of verification given the test result and observed covariates. This is estimated separately for those with positive and negative test results. The new method classifies the verified sample into several subsamples that have homogeneous propensity scores and allows correction for verification bias. Simulation studies demonstrate that the new estimators are more robust to model misspecification than existing methods, but still perform well when the models for the probability of disease and probability of verification are correctly specified.

    PMID: 21856650 [PubMed – as supplied by publisher]

    2. Prev Med. 2011 Aug 17. [Epub ahead of print]

    Null misinterpretation in statistical testing and its impact on health risk assessment. Greenland S.

    Statistical methods play a pivotal role in health risk assessment, but not always an enlightened one. Problems well known to academics are frequently overlooked in crucial nonacademic venues such as litigation, even though those venues can have profound impacts on population health and medical practice. Statisticians have focused heavily on how statistical significance overstates evidence against null hypotheses, but less on how statistical nonsignificance does not correspond to evidence for the null. I thus present an example of a highly credentialed statistical expert conflating high “nonsignificance” with strong support for the null, via misinterpretation of a P-value as a posterior probability of the null hypothesis. Reverse-Bayes analyses reveal that nearly all the support for the null claimed by the expert must have come from the expert’s prior, rather than the data, and that there was no background data that could support a strong prior. The example illustrates how carelessness about the actual meaning of P-values and confidence limits allow extremely biased prior opinions (including null-spiked opinions) to be presented as if they were objective inferences from the data.

    PMID: 21871481 [PubMed – as supplied by publisher]

    3. J Clin Epidemiol. 2011 Aug 11. [Epub ahead of print]

    The “best balance” allocation led to optimal balance in cluster-controlled trials. de Hoop E, Teerenstra S, van Gaal BG, Moerbeek M, Borm GF. Department of Epidemiology, Biostatistics and HTA, 133, Radboud University Nijmegen Medical Centre, PO Box 9101, 6500 HB Nijmegen, The Netherlands.

    OBJECTIVE: Balance of prognostic factors between treatment groups is desirable because it improves the accuracy, precision, and credibility of the results. In cluster-controlled trials, imbalance can easily occur by chance when the number of cluster is small. If all clusters are known at the start of the study, the “best balance” allocation method (BB) can be used to obtain optimal balance. This method will be compared with other allocation methods.

    STUDY DESIGN AND SETTING: We carried out a simulation study to compare the balance obtained with BB, minimization, unrestricted randomization, and matching for four to 20 clusters and one to five categorical prognostic factors at cluster level.

    RESULTS: BB resulted in a better balance than randomization in 13-100% of the situations, in 0-61% for minimization, and in 0-88% for matching. The superior performance of BB increased as the number of clusters and/or the number of factors increased.

    CONCLUSION: BB results in a better balance of prognostic factors than randomization, minimization, stratification, and matching in most situations. Furthermore, BB cannot result in a worse balance of prognostic factors than the other methods.

    PMID: 21840173 [PubMed – as supplied by publisher]

    4. Stat Med. 2011 Aug 4. doi: 10.1002/sim.4322. [Epub ahead of print]

    Subgroup identification from randomized clinical trial data. Foster JC, Taylor JM, Ruberg SJ. Department of Biostatistics, University of Michigan, Ann Arbor, MI, 48109, USA.

    We consider the problem of identifying a subgroup of patients who may have an enhanced treatment effect in a randomized clinical trial, and it is desirable that the subgroup be defined by a limited number of covariates. For this problem, the development of a standard, pre-determined strategy may help to avoid the well-known dangers of subgroup analysis. We present a method developed to find subgroups of enhanced treatment effect. This method, referred to as ‘Virtual Twins’, involves predicting response probabilities for treatment and control ‘twins’ for each subject. The difference in these probabilities is then used as the outcome in a classification or regression tree, which can potentially include any set of the covariates. We define a measure Q(Â) to be the difference between the treatment effect in estimated subgroup  and the marginal treatment effect. We present several methods developed to obtain an estimate of Q(Â), including estimation of Q(Â) using estimated probabilities in the original data, using estimated probabilities in newly simulated data, two cross-validation-based approaches, and a bootstrap-based bias-corrected approach. Results of a simulation study indicate that the Virtual Twins method noticeably outperforms logistic regression with forward selection when a true subgroup of enhanced treatment effect exists. Generally, large sample sizes or strong enhanced treatment effects are needed for subgroup estimation. As an illustration, we apply the proposed methods to data from a randomized clinical trial. Copyright © 2011 John Wiley & Sons, Ltd.

    PMID: 21815180 [PubMed – as supplied by publisher]

    5. Pharmacoepidemiol Drug Saf. 2011 Aug 2. doi: 10.1002/pds.2205. [Epub ahead of print]

    Record linkage for pharmacoepidemiological studies in cancer patients. Herk-Sukel MP, Lemmens VE, Poll-Franse LV, Herings RM, Coebergh JW. PHARMO Institute for Drug Outcomes Research, Utrecht, the Netherlands.

    BACKGROUND: An increasing need has developed for the post-approval surveillance of (new) anti-cancer drugs by means of pharmacoepidemiology and outcomes research in the area of oncology.

    OBJECTIVES: To create an overview that makes researchers aware of the available database linkages in Northern America and Europe which facilitate pharmacoepidemiology and outcomes research in cancer patients.

    METHODS: In addition to our own database, i.e. the Eindhoven Cancer Registry (ECR) linked to the PHARMO Record Linkage System, we considered database linkages between a population-based cancer registry and an administrative healthcare database that at least contains information on drug use and offers a longitudinal perspective on healthcare utilization. Eligible database linkages were limited to those that had been used in multiple published articles in English language included in Pubmed. The HMO Cancer Research Network (CRN) in the US was excluded from this review, as an overview of the linked databases participating in the CRN is already provided elsewhere. Researchers who had worked with the data resources included in our review were contacted for additional information and verification of the data presented in the overview.

    RESULTS: The following database linkages were included: the Surveillance, Epidemiology, and End-Results-Medicare; cancer registry data linked to Medicaid; Canadian cancer registries linked to population-based drug databases; the Scottish cancer registry linked to the Tayside drug dispensing data; linked databases in the Nordic Countries of Europe: Norway, Sweden, Finland and Denmark; and the ECR-PHARMO linkage in the Netherlands. Descriptives of the included database linkages comprise population size, generalizability of the population, year of first data availability, contents of the cancer registry, contents of the administrative healthcare database, the possibility to select a cancer-free control cohort, and linkage to other healthcare databases.

    CONCLUSIONS: The linked databases offer a longitudinal perspective, allowing for observations of health care utilization before, during, and after cancer diagnosis. They create new powerful data resources for the monitoring of post-approval drug utilization, as well as a framework to explore the cost-effectiveness of new, often expensive, anti-cancer drugs as used in everyday practice. Copyright © 2011 John Wiley & Sons, Ltd.

    PMID: 21812067 [PubMed – as supplied by publisher]

    CER Scan [published within the last 30 days]

    1. JAMA. 2011 Aug 24;306(8):848-55.

    Automated identification of postoperative complications within an electronic medical record using natural language processing. Murff HJ, FitzHenry F, Matheny ME, Gentry N, Kotter KL, Crimin K, Dittus RS, Rosen AK, Elkin PL, Brown SH, Speroff T. Tennessee Valley Healthcare System, Veterans Affairs Medical Center, Nashville, TN, USA.

    Comment in: JAMA. 2011 Aug 24;306(8):880-1.

    CONTEXT: Currently most automated methods to identify patient safety occurrences rely on administrative data codes; however, free-text searches of electronic medical records could represent an additional surveillance approach. OBJECTIVE: To evaluate a natural language processing search-approach to identify postoperative surgical complications within a comprehensive electronic medical record.

    DESIGN, SETTING, AND PATIENTS: Cross-sectional study involving 2974 patients undergoing inpatient surgical procedures at 6 Veterans Health Administration (VHA) medical centers from 1999 to 2006.

    MAIN OUTCOME MEASURES: Postoperative occurrences of acute renal failure requiring dialysis, deep vein thrombosis, pulmonary embolism, sepsis, pneumonia, or myocardial infarction identified through medical record review as part of the VA Surgical Quality Improvement Program. We determined the sensitivity and specificity of the natural language processing approach to identify these complications and compared its performance with patient safety indicators that use discharge coding information. RESULTS: The proportion of postoperative events for each sample was 2% (39 of 1924) for acute renal failure requiring dialysis, 0.7% (18 of 2327) for pulmonary embolism, 1% (29 of 2327) for deep vein thrombosis, 7% (61 of 866) for sepsis, 16% (222 of 1405) for pneumonia, and 2% (35 of 1822) for myocardial infarction. Natural language processing correctly identified 82% (95% confidence interval [CI], 67%-91%) of acute renal failure cases compared with 38% (95% CI, 25%-54%) for patient safety indicators. Similar results were obtained for venous thromboembolism (59%, 95% CI, 44%-72% vs 46%, 95% CI, 32%-60%), pneumonia (64%, 95% CI, 58%-70% vs 5%, 95% CI, 3%-9%), sepsis (89%, 95% CI, 78%-94% vs 34%, 95% CI, 24%-47%), and postoperative myocardial infarction (91%, 95% CI, 78%-97%) vs 89%, 95% CI, 74%-96%). Both natural language processing and patient safety indicators were highly specific for these diagnoses.

    CONCLUSION: Among patients undergoing inpatient surgical procedures at VA medical centers, natural language processing analysis of electronic medical records to identify postoperative complications had higher sensitivity and lower specificity compared with patient safety indicators based on discharge coding.

    PMID: 21862746 [PubMed – indexed for MEDLINE]

    2. JAMA. 2011 Aug 17;306(7):709; author reply 709-10.

    Efficacy research and unanswered clinical questions. Vohra S, Shamseer L, Sampson M.

    Comment on: JAMA. 2011 May 18;305(19):2005-6.

    PMID: 21846851 [PubMed – indexed for MEDLINE]

    3. Pharmacoepidemiol Drug Saf. 2011 Aug;20(8):858-65. doi: 10.1002/pds.2160. Epub 2011 Jun 13.
    Why do covariates defined by International Classification of Diseases codes fail to remove confounding in pharmacoepidemiologic studies among seniors? Jackson ML, Nelson JC, Jackson LA. Group Health Research Institute, Seattle, WA, USA.

    PURPOSE: The common practice of using administrative diagnosis codes as the sole source of data on potential confounders in pharmacoepidemiologic studies has been shown to leave substantial residual confounding. We explored reasons why adjustment for comorbid illness defined from International Classification of Diseases (ICD) codes fails to remove confounding.

    METHODS: We used data from a case-control study among immunocompetent seniors enrolled in Group Health to estimate bias in the estimated association between receipt of influenza vaccine and the risk of community-acquired pneumonia during non-influenza control periods and to estimate the effects of adjusting for comorbid illnesses defined from either ICD codes or the medical record. We also estimated the accuracy of ICD codes for identifying comorbid illnesses compared with the gold standard of medical record review.

    RESULTS: Sensitivity of ICD codes for illnesses recorded in the medical record ranged from 59 to 97% (median, 76%). Strong confounding was present in the vaccine/pneumonia association, as evidenced by the non-null odds ratio of 0.60 (95% confidence interval, 0.38-0.95) during this control period. Adjusting for the presence/absence of comorbid illnesses defined from either medical record review (odds ratio, 0.73) or from ICD codes (odds ratio, 0.68) left considerable residual confounding.

    CONCLUSIONS: ICD codes may fail to control for confounding because they often lack sensitivity for detecting comorbid illnesses and because measures of the presence/absence of comorbid illnesses may be insufficient to remove confounding. These findings call for caution in the use of ICD codes to control for confounding. Copyright © 2011 John Wiley & Sons, Ltd.

    PMID: 21671442 [PubMed – in process]

    4. J Clin Epidemiol. 2011 Aug;64(8):821-9. Epub 2010 Dec 30.

    Development and use of reporting guidelines for assessing the quality of validation studies of health administrative data. Benchimol EI, Manuel DG, To T, Griffiths AM, Rabeneck L, Guttmann A. The Institute for Clinical Evaluative Sciences, Toronto, Ontario, Canada.

    BACKGROUND AND OBJECTIVES: Validation of health administrative data for identifying patients with different health states (diseases and conditions) is a research priority, but no guidelines exist for ensuring quality. We created reporting guidelines for studies validating administrative data identification algorithms and used them to assess the quality of reporting of validation studies in the literature.

    METHODS: Using Standards for Reporting of Diagnostic accuracy (STARD) criteria as a guide, we created a 40-item checklist of items with which identification accuracy studies should be reported. A systematic review identified studies that validated identification algorithms using administrative data. We used the checklist to assess the quality of reporting.

    RESULTS: In 271 included articles, goals and data sources were well reported but few reported four or more statistical estimates of accuracy (36.9%). In 65.9% of studies reporting positive predictive value (PPV)/negative predictive value (NPV), the prevalence of disease in the validation cohort was higher than in the administrative data, potentially falsely elevating predictive values. Subgroup accuracy (53.1%) and 95% confidence intervals for accuracy measures (35.8%) were also underreported.

    CONCLUSIONS: The quality of studies validating health states in the administrative data varies, with significant deficits in reporting of markers of diagnostic accuracy, including the appropriate estimation of PPV and NPV. These omissions could lead to misclassification bias and incorrect estimation of incidence and health services utilization rates. Use of a reporting checklist, such as the one created for this study by modifying the STARD criteria, could improve the quality of reporting of validation studies, allowing for accurate application of algorithms, and interpretation of research using health administrative data.

    PMID: 21194889 [PubMed – indexed for MEDLINE]

    SEPTEMBER THEME: Application of Propensity Scores in CER of Surgical Interventions (This is a cross-section of studies published within the last year that demonstrate the level discussion in the field. The Methods Center does not necessarily endorse the studies’ methodology)

    1. Arch Surg. 2010 Oct;145(10):939-45.

    Introduction to propensity scores: A case study on the comparative effectiveness of laparoscopic vs open appendectomy. Hemmila MR, Birkmeyer NJ, Arbabi S, Osborne NH, Wahl WL, Dimick JB. Department of Surgery, University of Michigan Medical School, Ann Arbor, 48109-5033, USA.

    Comment in Arch Surg. 2010 Oct;145(10):945-6.

    OBJECTIVE: To demonstrate the use of propensity scores to evaluate the comparative effectiveness of laparoscopic and open appendectomy.

    DESIGN: Retrospective cohort study.

    SETTING: Academic and private hospitals.

    PATIENTS: 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.

    MAIN OUTCOME MEASURES: Patient morbidity and mortality, rate of return to operating room, and hospital length of stay.

    RESULTS: 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.

    CONCLUSIONS: 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.

    PMID: 20956761 [PubMed – indexed for MEDLINE]

    2. Arch Surg. 2011 Jul;146(7):887-8.

    Propensity score methods: setting the score straight. Mayo SC, Pawlik TM. Department of Surgery, Johns Hopkins University, 600 N Wolfe St, Blalock 655, Baltimore, MD 21287.

    PMID: 21768443 [PubMed – in process]

    3. J Thorac Cardiovasc Surg. 2011 Aug 13. [Epub ahead of print]

    On-pump and off-pump coronary artery bypass grafting in patients with left main stem disease: A propensity score analysis. Murzi M, Caputo M, Aresu G, Duggan S, Miceli A, Glauber M, Angelini GD. Bristol Heart Institute, University of Bristol, Bristol, UK.

    OBJECTIVE: This study compared safety and efficacy between off-pump coronary artery bypass grafting (OPCAB), a relatively new technique, and conventional on-pump coronary artery bypass grafting (CCAB) in patients with left main stem disease.

    METHODS: In a retrospective, observational, cohort study of prospectively collected data on 2375 consecutive patients with left main stem disease undergoing isolated CABG (1297 OPCAB, 1078 CCAB) between April 1996 and December 2009 at the Bristol Heart Institute, 548 patients undergoing OPCAB were matched with 548 patients undergoing CCAB by propensity score.

    RESULTS: After propensity matching, groups were comparable in preoperative characteristics. Relative to CCAB, OPCAB was associated with lower in-hospital mortality (0.5% vs 2.9%; P = .001), incidence of stroke (0% vs 0.9%; P = .02), postoperative renal dysfunction (4.9% vs 10.8%; P = .001), pulmonary complications (10.2% vs 16.6%; P = .002), and infectious complications (3.5% vs 6.2%; P = .03). The OPCAB group received fewer grafts than did the CCAB group (2.7 ± 0.7 vs 3 ± 0.7; P = .001) and had a lower rate of complete revascularization (88.3% vs 92%; P = .04). In multivariable analysis, cardiopulmonary bypass was confirmed to be an independent predictor of in-hospital mortality (odds ratio, 5.74; P = .001). Survivals at 1, 5, and 10 years were similar between groups (OPCAB, 96.8%, 87.3%, and 71.7%; CCAB, 96.8%, 88.6%, and 69.8%).

    CONCLUSIONS: OPCAB in patients with left main stem disease is a safe procedure with reduced early morbidity and mortality and similar long-term survival to conventional on-pump revascularization.

    PMID: 21843893 [PubMed – as supplied by publisher]

    4. J Thorac Cardiovasc Surg. 2011 Jun 16. [Epub ahead of print]

    Results of matching valve and root repair to aortic valve and root pathology.Svensson LG, Batizy LH, Blackstone EH, Marc Gillinov A, Moon MC, D’Agostino RS, Nadolny EM, Stewart WJ, Griffin BP, Hammer DF, Grimm R, Lytle BW. Department of Thoracic and Cardiovascular Surgery, Cleveland Clinic, Cleveland, Ohio.

    OBJECTIVE: For patients with aortic root pathology and aortic valve regurgitation, aortic valve replacement is problematic because no durable bioprosthesis exists, and mechanical valves require lifetime anticoagulation. This study sought to assess outcomes of combined aortic valve and root repair, including comparison with matched bioprosthesis aortic valve replacement.

    METHODS: From November 1990 to January 2005, 366 patients underwent modified David reimplantation (n = 72), root remodeling (n = 72), or valve repair with sinotubular junction tailoring (n = 222). Active follow-up was 99% complete, with a mean of 5.6 ± 4.0 years (maximum 17 years); follow-up for vital status averaged 8.5 ± 3.6 years (maximum 19 years). Propensity-adjusted models were developed for fair comparison of outcomes.

    RESULTS: Thirty-day and 5-, 10-, and 15-year survivals were 98%, 86%, 74%, and 58%, respectively, similar to that of the US matched population and better than that after bioprosthesis aortic valve replacement. Propensity-score-adjusted survival was similar across procedures (P > .3). Freedom from reoperation at 30 days and 5 and 10 years was 99%, 92%, and 89%, respectively, and was similar across procedures (P > .3) after propensity-score adjustment. Patients with tricuspid aortic valves were more likely to be free of reoperation than those with bicuspid valves at 10 years (93% vs 77%, P = .002), equivalent to bioprosthesis aortic valve replacement and superior after 12 years. Bioprostheses increasingly deteriorated after 7 years, and hazard functions for reoperation crossed at 7 years.

    CONCLUSIONS: Valve preservation (rather than replacement) and matching root procedures have excellent early and long-term results, with increasing survival benefit at 7 years and fewer reoperations by 12 years. We recommend this procedure for experienced surgical teams.

    PMID: 21683965 [PubMed – as supplied by publisher]

    5. Ann Surg. 2011 Feb;253(2):385-92.

    Can the impact of change of surgical teams in cardiovascular surgery be measured by operative mortality or morbidity? A propensity adjusted cohort comparison. Brown ML, Parker SE, Quiñonez LG, Li Z, Sundt TM. Division of Anesthesiology and Pain Medicine, University of Alberta, Edmonton, AB, Canada.

    OBJECTIVE: Our objective was to examine the impact of team changeover and unfamiliar teams in cardiovascular surgery on traditional clinical outcome measures.

    BACKGROUND: The importance of teamwork in the operating room is increasingly being appreciated, but the impact on more traditional outcome measures is unclear.

    METHODS: Elective or urgent cardiovascular procedures were divided into categories: team D (patients who had an operation with a day team); team E (patients who had an operation with an evening team); team C (patients who had an operation which included changeover between a day and evening team). Comparison groups were adjusted using propensity scores.

    RESULTS: We identified 6698 patients who met inclusion criteria (team D, n =3781; team E, n = 518; team C, n = 2399). After propensity score adjustment,there was an increased skin–skin time of 28 minutes in team C when compared with team D (P < 0.001) and of 21 minutes when compared with team E (P <0.001). There were also more episodes of septicemia among team C patients(OR 1.85, P = 0.013) when compared with team D. Patients operated by a day team had a statistically significantly lower number of ventilated hours and shorter hospital length of stay when compared with team E and team C (P < 0.001 and P < 0.001, respectively). There was no difference between teams in operative death, reoperation for bleeding, blood transfusion, renal failure/dialysis, neurologic events, or deep/superficial wound infections.

    CONCLUSIONS: The change in operating room personnel from the day team to the evening team added significant length to the total operating department time in cardiovascular surgery; however, its impact on most traditional outcome measures was difficult to demonstrate. More sensitive outcome measures may be required to assess the impact of teamwork interventions.

    PMID: 21173693 [PubMed – indexed for MEDLINE]

    6. J Thorac Cardiovasc Surg. 2011 Jan;141(1):72-80.e1-4. Epub 2010 Nov 19.

    Robotic repair of posterior mitral valve prolapse versus conventional approaches: potential realized. Mihaljevic T, Jarrett CM, Gillinov AM, Williams SJ, DeVilliers PA, Stewart WJ, Svensson LG, Sabik JF 3rd, Blackstone EH. Department of Thoracic and Cardiovascular Surgery, Heart and Vascular Institute, Cleveland Clinic, Cleveland, Ohio 44195, USA.

    OBJECTIVE: Robotic mitral valve repair is the least invasive approach to mitral valve repair, yet there are few data comparing its outcomes with those of conventional approaches. Therefore, we compared outcomes of robotic mitral valve repair with those of complete sternotomy, partial sternotomy, and right mini-anterolateral thoracotomy.

    METHODS: From January 2006 to January 2009, 759 patients with degenerative mitral valve disease and posterior leaflet prolapse underwent primary isolated mitral valve surgery by complete sternotomy (n = 114), partial sternotomy (n = 270), right mini-anterolateral thoracotomy (n = 114), or a robotic approach (n = 261). Outcomes were compared on an intent-to-treat basis using propensity-score matching.

    RESULTS: Mitral valve repair was achieved in all patients except 1 patient in the complete sternotomy group. In matched groups, median cardiopulmonary bypass time was 42 minutes longer for robotic than complete sternotomy, 39 minutes longer than partial sternotomy, and 11 minutes longer than right mini-anterolateral thoracotomy (P < .0001); median myocardial ischemic time was 26 minutes longer than complete sternotomy and partial sternotomy, and 16 minutes longer than right mini-anterolateral thoracotomy (P < .0001). Quality of mitral valve repair was similar among matched groups (P = .6, .2, and .1, respectively). There were no in-hospital deaths. Neurologic, pulmonary, and renal complications were similar among groups (P > .1). The robotic group had the lowest occurrences of atrial fibrillation and pleural effusion, contributing to the shortest hospital stay (median 4.2 days), 1.0, 1.6, and 0.9 days shorter than for complete sternotomy, partial sternotomy, and right mini-anterolateral thoracotomy (all P < .001), respectively.

    CONCLUSIONS: Robotic repair of posterior mitral valve leaflet prolapse is as safe and effective as conventional approaches. Technical complexity and longer operative times for robotic repair are compensated for by lesser invasiveness and shorter hospital stay.

    PMID: 21093881 [PubMed – indexed for MEDLINE]

    7. J Urol. 2011 Jan;185(1):111-5. Epub 2010 Nov 12.

    Comparative effectiveness of perineal versus retropubic and minimally invasive radical prostatectomy. Prasad SM, Gu X, Lavelle R, Lipsitz SR, Hu JC. Division of Urologic Surgery, Brigham and Women’s Hospital, Boston, Massachusetts, USA.

    Comment in

    J Urol. 2011 Jul;186(1):350-1; author reply 351.

    J Urol. 2011 Jul;186(1):351; author reply 351-2.

    PURPOSE: While perineal radical prostatectomy has been largely supplanted by retropubic and minimally invasive radical prostatectomy, it was the predominant surgical approach for prostate cancer for many years. In our population based study we compared the use and outcomes of perineal radical prostatectomy vs retropubic and minimally invasive radical prostatectomy.

    MATERIALS AND METHODS: We identified men diagnosed with prostate cancer from 2003 to 2005 who underwent perineal (452), minimally invasive (1,938) and retropubic (6,899) radical prostatectomy using Surveillance, Epidemiology and End Results-Medicare linked data through 2007. We compared postoperative 30-day and anastomotic stricture complications, incontinence and erectile dysfunction, and cancer therapy (hormonal therapy and/or radiotherapy).

    RESULTS: Perineal radical prostatectomy comprised 4.9% of radical prostatectomies during our study period and use decreased with time. On propensity score adjusted analysis men who underwent perineal vs retropubic radical prostatectomy had shorter hospitalization (median 2 vs 3 days, p < 0.001), received fewer heterologous transfusions (7.2% vs 20.8%, p < 0.001) and required less additional cancer therapy (4.9% vs 6.9%, p = 0.020). When comparing perineal vs minimally invasive radical prostatectomy men who underwent the former required more heterologous transfusions (7.2% vs 2.7%, p = 0.018) but experienced fewer miscellaneous medical complications (5.3% vs 10.0%, p = 0.045) and erectile dysfunction procedures (1.4 vs 2.3/100 person-years, p = 0.008). The mean and median expenditure for perineal radical prostatectomy in the first 6 months postoperatively was $1,500 less than for retropubic or minimally invasive radical prostatectomy (p < 0.001).

    CONCLUSIONS: Men who undergo perineal vs retropubic and minimally invasive radical prostatectomy experienced favorable outcomes associated with lower expenditure. Urologists may be abandoning an underused but cost-effective surgical approach that compares favorably with its successors.

    PMID: 21074198 [PubMed – indexed for MEDLINE]

    8. Ann Surg. 2010 Nov;252(5):765-73.

    Infrapopliteal percutaneous transluminal angioplasty versus bypass surgery as first-line strategies in critical leg ischemia: a propensity score analysis. Söderström MI, Arvela EM, Korhonen M, Halmesmäki KH, Albäck AN, Biancari F, Lepäntalo MJ, Venermo MA. Department of Vascular Surgery, Helsinki University Central Hospital, Helsinki, Finland.

    INTRODUCTION: Recently, endovascular revascularization (percutaneous transluminal angioplasty [PTA]) has challenged surgery as a method for the salvage of critically ischemic legs (CLI). Comparison of surgical and endovascular techniques in randomized controlled trials is difficult because of differences in patient characteristics. To overcome this problem, we adjusted the differences by using propensity score analysis.

    MATERIALS AND METHODS: The study cohort comprised 1023 patients treated for CLI with 262 endovascular and 761 surgical revascularization procedures to their crural or pedal arteries. A propensity score was used for adjustment in multivariable analysis, for stratification, and for one-to-one matching.

    RESULTS: In the overall series, PTA and bypass surgery achieved similar 5-year leg salvage (75.3% vs 76.0%), survival (47.5% vs 43.3%), and amputation-free survival (37.7% vs 37.3%) rates and similar freedom from any further revascularization (77.3% vs 74.4%), whereas freedom from surgical revascularization was higher after bypass surgery (94.3% vs 86.2%, P < 0.001). In propensity-score-matched pairs, outcomes did not differ, except for freedom from surgical revascularization, which was significantly higher in the bypass surgery group (91.4% vs 85.3% at 5 years, P = 0.045). In a subgroup of patients who underwent isolated infrapopliteal revascularization, PTA was associated with better leg salvage (75.5% vs 68.0%, P = 0.042) and somewhat lower freedom from surgical revascularization (78.8% vs 85.2%, P = 0.17). This significant difference in the leg salvage rate was also observed after adjustment for propensity score (P = 0.044), but not in propensity-score-matched pairs (P = 0.12).

    CONCLUSIONS: When feasible, infrapopliteal PTA as a first-line strategy is expected to achieve similar long-term results to bypass surgery in CLI when redo surgery is actively utilized.

    PMID: 21037432 [PubMed – indexed for MEDLINE]

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