Factors associated with the Journal Impact Factor (JIF) for Urology and Nephrology Journals.

PURPOSE: The Journal Impact Factor (JIF) is an index used to compare a journal's quality among academic journals and it is commonly used as a proxy for journal quality. We sought to examine the JIF in order to elucidate the main predictors of the index while generating awareness among scientific community regarding need to modify the index calculation in the attempt to turn it more accurate. MATERIALS AND METHODS: Under the Urology and Nephrology category in the Journal Citations Report Website, the top 17 Journals by JIF in 2011 were chosen for the study. All manuscripts' abstracts published from 2009-2010 were reviewed; each article was categorized based on its research design (Retrospective, Review, etc). T and correlation tests were performed for categorical and continuous variables respectively. The JIF was the dependent variable. All variables were then included in a multivariate model. RESULTS: 23,012 articles from seventeen journals were evaluated with a median of 1,048 (range=78-6,342) articles per journal. Journals with a society affiliation were associated with a higher JIF (p=0.05). Self-citations (rho=0.57, p=0.02), citations for citable articles (rho=0.73,p=0.001), citations to non-citable articles (rho=0.65,p=0.0046), and retrospective studies (rho=-0.51,p=0.03) showed a strong correlation. Slight modifications to include the non-citable articles in the denominator yield drastic changes in the JIF and the ranking of the journals. CONCLUSION: The JIF appears to be closely associated with the number of citable articles published. A change in the formula for calculating JIF to include all types of published articles in the denominator would result in a more accurate representation.

Evaluation of use of stage of tobacco epidemic to predict post-immigration smoking behaviors.

INTRODUCTION: This research uses the Lopez stage of tobacco epidemic model to evaluate post-immigration smoking behavior. Stage is a composite measure of tobacco norms of a country: smoking prevalence, cigarette consumption, and tobacco-related morbidity. The Lopez model characterizes the changing relationship between smoking prevalence and tobacco-related mortality and morbidity as a country progresses through the 4 successive stages of the tobacco epidemic. METHODS: Survey data from Southeast Asian and Latino immigrants (from stage 1 and stage 2 countries) (n = 2,076) were used to evaluate stage of tobacco epidemic of country of emigration. Stage was compared with standard acculturation measures and community identification measures to understand post-immigration smoking behavior in the United States. Comparative analysis by stage and gender includes bivariate associations and logistic regression models to predict post-immigration smoking behavior. RESULTS: Males:Pre-immigration prevalence and consumption rates of our study sample conform to prevalence and consumption of stage 1 and stage 2 countries predicted by the Lopez model. Post-immigration smoking uptake is equivalent to pre-immigration uptake for stage 1 males. The uptake rate for stage 2 males post-immigration is significantly lower (22.1%) than pre-immigration uptake (41.4%). Stage is a statistically significant predictor of post-immigration smoking uptake (OR = 3.08, CI = 1.82-5.22, p < .01). Females:Stage of country of birth is not significantly predictive of post-migration smoking uptake. CONCLUSIONS: The finding of stage to be a strong predictor of post-immigration smoking behavior among males provides a promising measurement tool. Prevalence and consumption of females in our study sample support the need for revisions to the stage model.

Intensity modulated radiation therapy replaces 3-dimensional conformal radiotherapy as prostate cancer treatment.

PURPOSE: We describe trends in the use of intensity modulated radiotherapy vs 3-dimensional conformal radiotherapy for prostate cancer and identified predictors of intensity modulated radiotherapy use. MATERIALS AND METHODS: From the SEER (Surveillance, Epidemiology and End Results)-Medicare database we identified 52,290 men with incident nonmetastatic prostate cancer from 2000 to 2007 who were treated with radiotherapy. We tracked trends in the use of intensity modulated radiotherapy, 3-dimensional conformal radiotherapy, brachytherapy and combinations. Patient demographic and clinical characteristics were described and compared using chi-square and multivariate logistic regression. Trends at the place of service were also examined. RESULTS: Intensity modulated radiotherapy use increased from 1% of all radiotherapy in 2000 to 70% in 2007. Three-dimensional conformal radiotherapy use decreased from 75% to 12%. Most cases were treated with intensity modulated radiotherapy monotherapy. In 2007, 12% of the cohort received intensity modulated radiotherapy plus brachytherapy. In 2005, 81% of all external radiation was given as intensity modulated radiotherapy. Except for geography there were minimal differences in patient demographic and clinical characteristics between those treated with 3-dimensional conformal radiotherapy vs intensity modulated radiotherapy. On multivariate analysis significant predictors of the odds of receiving intensity modulated radiotherapy vs 3-dimensional conformal radiotherapy were low Gleason score, high education, white or Asian race and urban place of residence. The odds of receiving intensity modulated radiotherapy varied greatly by registry. A lesser part of the growth in intensity modulated radiotherapy use occurred at freestanding facilities. CONCLUSIONS: Intensity modulated radiotherapy has replaced 3-dimensional conformal radiotherapy as the primary form of external radiation for prostate cancer. The choice of intensity modulated radiotherapy over 3-dimensional conformal radiotherapy is not related to common clinical factors such as age, comorbidities or tumor aggressiveness. Although geographic variations exist, by 2007 intensity modulated radiotherapy dominated in all regions studied.

Bias due to missing SEER data in D'Amico risk stratification of prostate cancer.

PURPOSE: We examined the degree of exclusion bias that may occur due to missing data when grouping prostate cancer cases from the SEER (Surveillance, Epidemiology and End Results) database into D'Amico clinical risk groups. Exclusion bias may occur since D'Amico staging requires all 3 variables to be known and data may not be missing at random. MATERIALS AND METHODS: From the SEER database we identified 132,606 men with incident prostate cancer from 2004 to 2006. We documented age, race, Gleason score, clinical T stage, PSA and geographic region. Men were categorized into D'Amico risk groups. Those with 1 or more unknown tumor variables (prostate specific antigen, T stage and/or Gleason score) were labeled unclassified. We compared the value of the other 2 known clinical variables for men with known vs unknown prostate specific antigen, Gleason score and T stage. Demographics were compared for those with and without missing data. Results were compared using chi-square and logistic regression. RESULTS: Of the men 33% had 1 or more unknown tumor variables with T stage the most commonly missing variable. There was no clinically significant difference in the value of the other 2 known tumor variables when T stage or prostate specific antigen was missing. Men older than 75 years were more likely to have unknown variables than younger men. There was significant geographic variation in the frequency of unclassified D'Amico data. CONCLUSIONS: In studies in which the data set is limited to men who can be classified into a D'Amico risk group 33% of eligible patients are excluded from analysis. Such men are older and from certain SEER registries but they have tumor characteristics similar to those with complete data.

Factors associated with the Journal Impact Factor (JIF) for Urology and Nephrology Journals

Purpose: The Journal Impact Factor (JIF) is an index used to compare a journal's quality among academic journals and it is commonly used as a proxy for journal quality. We sought to examine the JIF in order to elucidate the main predictors of the index while generating awareness among scientific community regarding need to modify the index calculation in the attempt to turn it more accurate. Materials and Methods: Under the Urology and Nephrology category in the Journal Citations Report Website, the top 17 Journals by JIF in 2011 were chosen for the study. All manuscripts’ abstracts published from 2009-2010 were reviewed; each article was categorized based on its research design (Retrospective, Review, etc). T and correlation tests were performed for categorical and continuous variables respectively. The JIF was the dependent variable. All variables were then included in a multivariate model. Results: 23,012 articles from seventeen journals were evaluated with a median of 1,048 (range=78-6,342) articles per journal. Journals with a society affiliation were associated with a higher JIF (p=0.05). Self-citations (rho=0.57, p=0.02), citations for citable articles (rho=0.73, p=0.001), citations to non-citable articles (rho=0.65, p=0.0046), and retrospective studies (rho=-0.51, p=0.03) showed a strong correlation. Slight modifications to include the non-citable articles in the denominator yield drastic changes in the JIF and the ranking of the journals. Conclusion: The JIF appears to be closely associated with the number of citable articles published. A change in the formula for calculating JIF to include all types of published articles in the denominator would result in a more accurate representation.