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Open Access Research article

Systematic review and meta-analysis: influence of smoking cessation on incidence of pneumonia in HIV

Preeti De1, Amanda Farley1, Nicola Lindson1 and Paul Aveyard12*

Author affiliations

1 Primary Care Clinical Sciences, University of Birmingham, Birmingham, B15 2TT, UK

2 Primary Care Health Sciences, University of Oxford, Radcliffe Observatory Quarter, Woodstock Road, Oxford, OX2 6GG, UK

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Citation and License

BMC Medicine 2013, 11:15  doi:10.1186/1741-7015-11-15

Published: 22 January 2013

Abstract

Background

Smoking is common in people infected with HIV but cessation support is not a routine part of clinical care. The aim was to assess whether smoking is a risk factor for pneumonia in people with HIV and whether smoking cessation ameliorates excess risk.

Methods

We performed MEDLINE and Embase database searches and included cohort or case-control studies conducted in adult patients infected with HIV extracting a hazard ratio (HR) or odds ratio (OR) that compared the incidence of bacterial pneumonia or pneumonia caused by Pneumocystis jiroveci (PCP) between two smoking categories. Studies were appraised for quality and combined using inverse variance meta-analysis.

Results

Fourteen cohort and case-control studies were included. Assessment of outcome was good, but assessment of exposure status was poor. Current smokers were at higher risk of bacterial pneumonia than former smokers: HR 1.37 (95% confidence interval (CI): 1.06, 1.78). There was no evidence that former smokers were at higher risk than never smokers: HR 1.24 (95%CI: 0.96, 1.60). Current smokers were at higher risk of bacterial pneumonia than current non-smokers: HR of 1.73 (95%CI: 1.44, 2.06). There was no evidence that smoking increased the incidence of PCP. The HR for current versus non-smokers was 0.94 (95%CI: 0.79, 1.12), but from case-control studies the OR was 1.76 (95%CI: 1.25, 2.48) with heterogeneity. Confined to higher quality studies, the OR was 0.97 (95%CI: 0.81, 1.16). Residual confounding is possible, but available data suggest this is not an adequate explanation.

Conclusions

Smoking is a risk factor for bacterial pneumonia but not PCP and smoking cessation reduces this risk.

See related article: http://www.biomedcentral.com/1741-7015/11/16 webcite

Keywords:
HIV; meta-analysis; pneumonia; smoking; smoking cessation