title: Prevalence of viral infection detected by PCR and RT-PCR in patients with acute exacerbation of COPD: a systematic review.
abstract: OBJECTIVE
  Viruses are important aetiological agents of acute exacerbation of COPD (AECOPD). Their reported prevalence varies from region to region. This systematic review calculated the prevalence of respiratory viral infections in AECOPD.
  
  
  METHODS
  A systematic search was performed using Medline, and references of relevant articles and conference proceedings were hand searched. Articles for review were selected based on the following criteria: (i) prospective or cross-sectional study, (ii) original research, (iii) viral detection used the highly sensitive techniques of PCR and/or Reverse Transcriptase PCR (RT-PCR), (iv) viral prevalence in AECOPD defined, and (v) full paper available in English. We assessed the study quality and extracted data independently and in duplicate using a pre-defined data extraction form. Weighted mean prevalence (WMP) was calculated and a forest plot was constructed to show the dispersion.
  
  
  RESULTS
  Eight studies met the inclusion criteria. The WMP of respiratory viral infection in AECOPD was 34.1% (95% CI: 23.9-44.4). picornavirus was the most commonly detected virus with WMP 17.3% (95% CI: 7.2-27.3), followed by influenza; 7.4% (95% CI: 2.9-12.0), respiratory syncytial virus; 5.3% (95% CI: 1.6-9.0), corona viruses; 3.1% (95% CI: 0.4-5.8), parainfluenza; 2.6% (95% CI: 0.4-4.8), adenovirus; 1.1% (95% CI: -1.1 to 3.3), and human metapneumovirus; 0.7% (95% CI: -0.3 to 1.8). Maximum WMP was observed in studies from Europe followed by the USA, Australia and Asia. Picorna was the most common virus detected in Western countries whereas influenza was most common in Asia.
  
  
  CONCLUSIONS
  This systematic review demonstrated that viruses are strongly associated with AECOPD, with the highest detection rates of viruses being in Europe. The geographical epidemiology of viruses may have important therapeutic implications for management of AECOPD.
authors.affiliation: Department of Medicine, All India Institute of Medical Sciences, New Delhi, India. anantmohan@yahoo.com
authors.forename: Anant
authors.initials: A
authors.lastname: Mohan
authors.forename: Subhash
authors.initials: S
authors.lastname: Chandra
authors.forename: Dipti
authors.initials: D
authors.lastname: Agarwal
authors.forename: Randeep
authors.initials: R
authors.lastname: Guleria
authors.forename: Shobha
authors.initials: S
authors.lastname: Broor
authors.forename: Bharti
authors.initials: B
authors.lastname: Gaur
authors.forename: Ravindra Mohan
authors.initials: RM
authors.lastname: Pandey
mesh_terms: D015897:Comorbidity; D006801:Humans; D016133:Polymerase Chain Reaction; D015995:Prevalence; D029424:Pulmonary Disease, Chronic Obstructive / Q000453:epidemiology* / Q000821:virology*; D020133:Reverse Transcriptase Polymerase Chain Reaction; D014777:Virus Diseases / Q000175:diagnosis / Q000453:epidemiology*