Abhaya V. Kulkarni

Comparisons of Citations in Web of Science, Scopus, and Google Scholar for Articles Published in General Medical Journals

CONTEXT Until recently, Web of Science was the only database available to track citation counts for published articles. Other databases are now available, but their relative performance has not been established. OBJECTIVE To compare the citation count profiles of articles published in general medical journals among the citation databases of Web of Science, Scopus, and Google Scholar. DESIGN Cohort study of 328 articles published in JAMA, Lancet, or the New England Journal of Medicine between October 1, 1999, and March 31, 2000. Total citation counts for each article up to June 2008 were retrieved from Web of Science, Scopus, and Google Scholar. Article characteristics were analyzed in linear regression models to determine interaction with the databases. MAIN OUTCOME MEASURES Number of citations received by an article since publication and article characteristics associated with citation in databases. RESULTS Google Scholar and Scopus retrieved more citations per article with a median of 160 (interquartile range [IQR], 83 to 324) and 149 (IQR, 78 to 289), respectively, than Web of Science (median, 122; IQR, 66 to 241) (P < .001 for both comparisons). Compared with Web of Science, Scopus retrieved more citations from non-English-language sources (median, 10.2% vs 4.1%) and reviews (30.8% vs 18.2%), and fewer citations from articles (57.2% vs 70.5%), editorials (2.1% vs 5.9%), and letters (0.8% vs 2.6%) (all P < .001). On a log(10)-transformed scale, fewer citations were found in Google Scholar to articles with declared industry funding (nonstandardized regression coefficient, -0.09; 95% confidence interval [CI], -0.15 to -0.03), reporting a study of a drug or medical device (-0.05; 95% CI, -0.11 to 0.01), or with group authorship (-0.29; 95% CI, -0.35 to -0.23). In multivariable analysis, group authorship was the only characteristic that differed among the databases; Google Scholar had significantly fewer citations to group-authored articles (-0.30; 95% CI, -0.36 to -0.23) compared with Web of Science. CONCLUSION Web of Science, Scopus, and Google Scholar produced quantitatively and qualitatively different citation counts for articles published in 3 general medical journals.

A systematic review of the effects of resident duty hour restrictions in surgery: impact on resident wellness, training, and patient outcomes.

Background:In 2003, the Accreditation Council for Graduate Medical Education (ACGME) mandated 80-hour resident duty limits. In 2011 the ACGME mandated 16-hour duty maximums for PGY1 (post graduate year) residents. The stated goals were to improve patient safety, resident well-being, and education. A systematic review and meta-analysis were performed to evaluate the impact of resident duty hours (RDH) on clinical and educational outcomes in surgery. Methods:A systematic review (1980–2013) was executed on CINAHL, Cochrane Database, Embase, Medline, and Scopus. Quality of articles was assessed using the GRADE guidelines. Sixteen-hour shifts and night float systems were analyzed separately. Articles that examined mortality data were combined in a random-effects meta-analysis to evaluate the impact of RDH on patient mortality. Results:A total of 135 articles met the inclusion criteria. Among these, 42% (N = 57) were considered moderate-high quality. There was no overall improvement in patient outcomes as a result of RDH; however, some studies suggest increased complication rates in high-acuity patients. There was no improvement in education related to RDH restrictions, and performance on certification examinations has declined in some specialties. Survey studies revealed a perception of worsened education and patient safety. There were improvements in resident wellness after the 80-hour workweek, but there was little improvement or negative effects on wellness after 16-hour duty maximums were implemented. Conclusions:Recent RDH changes are not consistently associated with improvements in resident well-being, and have negative impacts on patient outcomes and performance on certification examinations. Greater flexibility to accommodate resident training needs is required. Further erosion of training time should be considered with great caution.

Endovascular Thrombectomy for Acute Ischemic Stroke: A Meta-analysis

IMPORTANCE Endovascular intervention for acute ischemic stroke improves revascularization. But trials examining endovascular therapy yielded variable functional outcomes, and the effect of endovascular intervention among subgroups needs better definition. OBJECTIVE To examine the association between endovascular mechanical thrombectomy and clinical outcomes among patients with acute ischemic stroke. DATA SOURCES We systematically searched MEDLINE, EMBASE, CINAHL, Google Scholar, and the Cochrane Library without language restriction through August 2015. STUDY SELECTION Eligible studies were randomized clinical trials of endovascular therapy with mechanical thrombectomy vs standard medical care, which includes the use of intravenous tissue plasminogen activator (tPA). DATA EXTRACTION AND SYNTHESIS Independent reviewers evaluated the quality of studies and abstracted the data. We calculated odds ratios (ORs) and 95% CIs for all outcomes using random-effects meta-analyses and performed subgroup and sensitivity analyses to examine whether certain imaging, patient, treatment, or study characteristics were associated with improved functional outcome. The strength of the evidence was examined for all outcomes using the GRADE method. MAIN OUTCOMES AND MEASURES Ordinal improvement across modified Rankin scale (mRS) scores at 90 days, functional independence (mRS score, 0-2), angiographic revascularization at 24 hours, symptomatic intracranial hemorrhage within 90 days, and all-cause mortality at 90 days. RESULTS Data were included from 8 trials involving 2423 patients (mean [SD] age, 67.4 [14.4] years; 1131 [46.7%] women), including 1313 who underwent endovascular thrombectomy and 1110 who received standard medical care with tPA. In a meta-analysis of these trials, endovascular therapy was associated with a significant proportional treatment benefit across mRS scores (OR, 1.56; 95% CI, 1.14-2.13; P = .005). Functional independence at 90 days (mRS score, 0-2) occurred among 557 of 1293 patients (44.6%; 95% CI, 36.6%-52.8%) in the endovascular therapy group vs 351 of 1094 patients (31.8%; 95% CI, 24.6%-40.0%) in the standard medical care group (risk difference, 12%; 95% CI, 3.8%-20.3%; OR, 1.71; 95% CI, 1.18-2.49; P = .005). Compared with standard medical care, endovascular thrombectomy was associated with significantly higher rates of angiographic revascularization at 24 hours (75.8% vs 34.1%; OR, 6.49; 95% CI, 4.79-8.79; P < .001) but no significant difference in rates of symptomatic intracranial hemorrhage within 90 days (70 events [5.7%] vs 53 events [5.1%]; OR, 1.12; 95% CI, 0.77-1.63; P = .56) or all-cause mortality at 90 days (218 deaths [15.8%] vs 201 deaths [17.8%]; OR, 0.87; 95% CI, 0.68-1.12; P = .27). CONCLUSIONS AND RELEVANCE Among patients with acute ischemic stroke, endovascular therapy with mechanical thrombectomy vs standard medical care with tPA was associated with improved functional outcomes and higher rates of angiographic revascularization, but no significant difference in symptomatic intracranial hemorrhage or all-cause mortality at 90 days.

Endoscopic Third Ventriculostomy in the Treatment of Childhood Hydrocephalus

OBJECTIVE To develop a model to predict the probability of endoscopic third ventriculostomy (ETV) success in the treatment for hydrocephalus on the basis of a childs individual characteristics. STUDY DESIGN We analyzed 618 ETVs performed consecutively on children at 12 international institutions to identify predictors of ETV success at 6 months. A multivariable logistic regression model was developed on 70% of the dataset (training set) and validated on 30% of the dataset (validation set). RESULTS In the training set, 305/455 ETVs (67.0%) were successful. The regression model (containing patient age, cause of hydrocephalus, and previous cerebrospinal fluid shunt) demonstrated good fit (Hosmer-Lemeshow, P = .78) and discrimination (C statistic = 0.70). In the validation set, 105/163 ETVs (64.4%) were successful and the model maintained good fit (Hosmer-Lemeshow, P = .45), discrimination (C statistic = 0.68), and calibration (calibration slope = 0.88). A simplified ETV Success Score was devised that closely approximates the predicted probability of ETV success. CONCLUSIONS Children most likely to succeed with ETV can now be accurately identified and spared the long-term complications of CSF shunting.

Characteristics Associated with Citation Rate of the Medical Literature

Background The citation rate for articles is viewed as a measure of their importance and impact; however, little is known about what features of articles are associated with higher citation rate. Methodology/Principal Findings We conducted a cohort study of all original articles, regardless of study methodology, published in the Lancet, JAMA, and New England Journal of Medicine, from October 1, 1999 to March 31, 2000. We identified 328 articles. Two blinded, independent reviewers extracted, in duplicate, nine variables from each article, which were analyzed in both univariable and multivariable linear least-squares regression models for their association with the annual rate of citations received by the article since publication. A two-way interaction between industry funding and an industry-favoring result was tested and found to be significant (p = 0.02). In our adjusted analysis, the presence of industry funding and an industry-favoring result was associated with an increase in annual citation rate of 25.7 (95% confidence interval, 8.5 to 42.8) compared to the absence of both industry funding and industry-favoring results. Higher annual rates of citation were also associated with articles dealing with cardiovascular medicine (13.3 more; 95% confidence interval, 3.9 to 22.3) and oncology (12.6 more; 95% confidence interval, 1.2 to 24.0), articles with group authorship (11.1 more; 95% confidence interval, 2.7 to 19.5), larger sample size and journal of publication. Conclusions/Significance Large trials, with group authorship, industry-funded, with industry-favoring results, in oncology or cardiology were associated with greater subsequent citations.

Occult Spinal Dysraphism: Clinical and Urodynamic Outcome after Division of the Filum Terminale

A highly select group of 31 patients presenting with urinary incontinence failed to respond to conservative management and were found to have unstable bladders and spina bifida occulta. After thorough evaluation they were suspected of having neurogenic bladder dysfunction possibly due to a tethered cord. Following division of the filum terminale daytime incontinence resolved in 72%, urodynamic detrusor hyperreflexia disappeared in 59% and bladder compliance improved in 66% of the patients. The operation was well tolerated and did not result in any neurological complications. The clinical, radiological and urodynamic characteristics of these patients before and after treatment are reported.

Conservative Management of Asymptomatic Spinal Lipomas of the Conus

OBJECTIVEThe natural history of spinal lipomas of the conus (SLCs) has not been well studied. Because of disappointing long-term results with early surgical treatment of asymptomatic children with SLCs, we have followed a protocol of conservative management for these patients. The results are presented in this report. METHODSSince 1994, all asymptomatic children with SLCs who were examined at Necker-Enfants Malades Hospital were subject to a protocol of conservative management. The records for those patients were reviewed, to determine the incidence and timing of neurological deterioration. The findings were compared with those for a previously reported historical cohort of asymptomatic patients who underwent early surgery at our institution. RESULTSFifty-three asymptomatic children (35 girls and 18 boys) with SLCs were monitored, with conservative management. During a mean follow-up period of 4.4 years (range, 12 mo to 9 yr), 13 patients (25%) exhibited neurological deterioration. At 9 years, the actuarial risks of deterioration, as determined with the Kaplan-Meier method, were 33% for the conservatively treated patients and 46% for the surgically treated patients. With a Cox proportional-hazards model, there was no significant difference in the risks of neurological deterioration for patients who were treated conservatively and those who underwent early surgery. CONCLUSIONThe incidences and patterns of neurological deterioration seemed to be very similar, regardless of whether early surgery was performed. These results suggest that conservative treatment of asymptomatic patients is a reasonable option. A more definitive randomized study will be required to clarify the relative efficacy of early surgery for SLCs among asymptomatic patients.

Lumboperitoneal shunting: a retrospective study in the pediatric population.

There is a shortage of data concerning the long-term follow-up of patients with lumboperitoneal (LP) shunts, especially in the pediatric population. A retrospective study of 143 patients who underwent LP shunting between 1974 and 1991 was therefore performed. The mean age at the time of shunt insertion was 3.3 years (range, 18 d to 17.8 yr), and the indication for shunting was: hydrocephalus (81%), cerebrospinal fluid fistula (12%), and pseudotumor cerebri (7%). The mean follow-up time was 5.7 years (range, 5 d to 17.5 yr), and during this period, there were five deaths of which one was shunt related (2.5 yr post-shunt insertion). Of the types of LP shunt used during the study period, the T-tube shunt (101 patients) fared significantly better (P = 0.003) than the percutaneous type (42 patients), and the overall survival characteristics for the T-tube shunt approximated those seen for ventriculoperitoneal shunts, with a 50% probability of remaining free of malfunctions for 5 years. A high rate of migration (19%) was partially responsible for the poor performance of the percutaneous-type shunts. By the end of the study, 40 patients (28%) had been converted to ventricular shunts, and this rate of conversion was similar for both shunt types. LP shunts have certain advantages over other forms of cerebrospinal fluid diversion and were successfully used for various clinical conditions during this study.(ABSTRACT TRUNCATED AT 250 WORDS)

A standardized protocol to reduce cerebrospinal fluid shunt infection: The Hydrocephalus Clinical Research Network Quality Improvement Initiative

OBJECT Quality improvement techniques are being implemented in many areas of medicine. In an effort to reduce the ventriculoperitoneal shunt infection rate, a standardized protocol was developed and implemented at 4 centers of the Hydrocephalus Clinical Research Network (HCRN). METHODS The protocol was developed sequentially by HCRN members using the current literature and prior institutional experience until consensus was obtained. The protocol was prospectively applied at each HCRN center to all children undergoing a shunt insertion or revision procedure. Infections were defined on the basis of CSF, wound, or pseudocyst cultures; wound breakdown; abdominal pseudocyst; or positive blood cultures in the presence of a ventriculoatrial shunt. Procedures and infections were measured before and after protocol implementation. RESULTS Twenty-one surgeons at 4 centers performed 1571 procedures between June 1, 2007, and February 28, 2009. The minimum follow-up was 6 months. The Network infection rate decreased from 8.8% prior to the protocol to 5.7% while using the protocol (p = 0.0028, absolute risk reduction 3.15%, relative risk reduction 36%). Three of 4 centers lowered their infection rate. Shunt surgery after external ventricular drainage (with or without prior infection) had the highest infection rate. Overall protocol compliance was 74.5% and improved over the course of the observation period. Based on logistic regression analysis, the use of BioGlide catheters (odds ratio [OR] 1.91, 95% CI 1.19-3.05; p = 0.007) and the use of antiseptic cream by any members of the surgical team (instead of a formal surgical scrub by all members of the surgical team; OR 4.53, 95% CI 1.43-14.41; p = 0.01) were associated with an increased risk of infection. CONCLUSIONS The standardized protocol for shunt surgery significantly reduced shunt infection across the HCRN. Overall protocol compliance was good. The protocol has established a common baseline within the Network, which will facilitate assessment of new treatments. Identification of factors associated with infection will allow further protocol refinement in the future.

Measurement of Ventricular Size: Reliability of the Frontal and Occipital Horn Ratio Compared to Subjective Assessment

Introduction: The frontal and occipital horn ration (FOR) has recently been described as a simple, linear measurement of ventricular size that correlates very well with ventricular volume. This study further characterizes the measurement properties of the FOR by investigating its interobserver reliability and comparing it to a subjective assessment of ventricular size. Methods: Axial images (CT and MR) of children with hydrocephalus taken before and after third ventriculostomy were reviewed by 4 independent observers. Two observers were blinded to patient identity and clinical status and 2 observers were nonblinded. Each observer independently recorded linear measurements from which the FOR was calculated for each image. Each reviewer also made a separate subjective assessment of the degree of hydrocephalus on a 9-point adjectival scale. Reliability was calculated using a repeated-measures analysis of variance (ANOVA) and an intraclass correlation coefficient (ICC) with random image and observer effects. Results: There were 120 separate observations (4 observers, 30 images). The FOR ranged from 0.33 to 0.75 (mean 0.55, standard deviation 0.11). The reliability coefficient was 0.93 (95% confidence interval, CI 0.80–0.97) between the 2 blinded observers and 0.98 (95% CI, 0.95–0.99) between the 2 nonblinded observer. The overall interobserver reliability for all 4 observers was 0.95 (95% CI 0.92–0.98). The mean FOR for each observer was very similar, regardless of the observer’s blinding status. However, the reliability of the observers’ subjective assessment of the hydrocephalus was much lower (ICC = 0.77, 95% CI 0.60–0.88). Conclusions: The FOR demonstrates excellent interobserver reliability (>0.9) and was superior to subjective assessments of hydrocephalus. In this study, excellent reliability was maintained regardless of the blinding status of the observers. This further demonstrates the properties of the FOR as a simple and reproducible measure of ventricular size. It is suitable for use in clinical studies, possibly even in situations in which observer blinding is not possible.