SPECIAL TOPICS

Chronic Obstructive Pulmonary Disease (COPD)

Published: January 2010

The baseline time span for this database is (publication years) 1999-October 31, 2009 from the fifth bimonthly update (a 10-year + 10-month period). The resulting database contained 15,996 (10 years) and 5,914 (2 years) papers; 46,590 authors; 113 nations; 2,046 journals; and 9,945 institutions. See additional paper information below in the overview & methodology sections.

OVERVIEW

Chronic obstructive pulmonary disease (COPD) is a progressive disease of the lungs that makes breathing difficult—either through overproduction of mucus, which causes the lungs to be clogged, or through damage to the lungs themselves, such as inflammation of the airway walls. The leading cause of COPD is cigarette smoking, but long-term exposure to other substances that can irritate the lungs, such as air pollution or chemical fumes, can also contribute. According to the National Heart, Lung and Blood Institute, COPD is the fourth-leading cause of death in the United States today, and while over 12 million people are currently living with a diagnosis of COPD, a further 12 million are likely living with the disease but are not aware of it. COPD has no cure at this time.

This month, ScienceWatch.com examines the literature on COPD over the past decade and over the past two years. To construct the initial data pool, the string "chronic obstructive pulmonary*" OR "COPD" OR "emphysema*" OR "chronic obstructive bronchitis*" OR "chronic obstructive airway*" OR "chronic obstructive lung*" was employed to search titles, abstracts, and keywords of original articles, reviews, and proceedings papers published between January 1, 1999 and October 31, 2009. To make the paper lists more on-target to the topic, we restricted to the following title keywords: "chronic obstruct*" OR "COPD" OR "emphysema."

The search for the optimal treatment for COPD dominates both the ten-year and two-year lists, with many large-scale clinical trials garnering citation attention, including but not limited to the TORCH, ISOLDE, TRISTAN, UPLIFT, and INSPIRE trials. The GOLD executive summary is covered on both lists.

Other topics examined in the past decade include lung-volume-reduction surgery, the nature of small-airway obstruction, multidimensional grading systems, the relationship between exacerbation frequency and lung function decline, the causative role of bacterial strains in exacerbations, and the role of the inhibition of VEGF receptors in emphysema. Standards for diagnosis and treatment and the molecular and cellular mechanisms of COPD are reviewed.

Other areas of interest on the two-year list include the use of C-reactive protein as a prognosis predictor, inhaled corticosteroid use and the risk of hospitalization for pneumonia, reduced mortality in COPD patients using statins, a review and meta-analysis of inhaled anticholinergics and major adverse cardiovascular events, depressive symptoms in COPD, the role of antielastin autoimmunity in smoking-induced emphysema patients, and treating concomitant COPD and chronic heart failure. The global burden of COPD, the outcomes of pharmacological trials, and the immunology of COPD are reviewed.

Methodology: Methodology: The baseline time span for this database is (publication years) 1999-October 31, 2009 from the fifth bimonthly update (a 10-year + 10-month period). The resulting database contained 15,996 (10 years) and 5,914 (2 years) papers; 46,590 authors; 113 nations; 2,046 journals; and 9,945 institutions. See additional paper information below in the overview & methodology sections.

Rankings: Once the database was in place, it was used to generate list of authors, journals, institutions, and nations. Rankings for author, journal, institution, and country are listed in three ways: according to total cites, total papers, and total cites/paper*. The paper thresholds and corresponding percentages used to determine scientist, institution, country, and journal rankings according to total cites/paper, and total papers respectively are as follows:

Entity	Authors	Institutions	Nations	Journals
Thresholds	12	53	5	5
Percentage:	1%	1%	50%	50%
*Unless otherwise specified, all rankings have a 5 paper threshold for all measures.