Table 1. Prevalence estimates of chronic obstructive pulmonary disease (COPD) in HIV-infected populations in the current antiretroviral era, listed in order of descending sample size.

Studies included are those that used spirometry to define COPD (not self-report or administrative data). Spirometry-based definitions of COPD vary, with most guidelines suggesting use of post-bronchodilator spirometry (e.g. at least 15 minutes after inhalation of 360-400 mcg of albuterol/salbutamol), although practical concerns such as time, training, and contraindications to bronchodilators can make such studies more challenging. A FEV₁/FVC ratio of <0.7 is a commonly used definition, but may underdiagnose COPD in younger patients and overdiagnose COPD in older patients. As such, some have advocated for use of a lower limit of normal (LLN) definition, which adjusts for variables such as age and gender, then defines COPD as those with a FEV₁/FVC ratio <5^th percentile adjusted for these clinical variables. Specific definitions used in each study are detailed in this table.

Author	n	Study years	Setting	% of current / former cigarette smokers	COPD definition and prevalence
Drummond10	316	2007 - 2010	USA	85% / 10%	Pre-bronchodilator FEV1/FVC <0.7 present in 16% at baseline
George11	234	2003 - 2004	USA	37% / 23%	Pre-bronchodilator FEV1/FVC<0.7 present in 6.8% (<LLN in 8.6%)
Gingo12	167	2007 - 2009	USA	53% / 23%	Post-bronchodilator FEV1/FVC <0.7 present in 21% (<LLN in 19%)
Cui13	119	n.r.	Canada	44% / 19%	Post-bronchodilator FEV1/FVC <0.7 present in 3%
Madeddu14	111	2006 - 2007	Italy	57% / n.r.	Post-bronchodilator FEV1/FVC<0.7 present in 23%
Hirani15	98	2008 - 2009	USA	21% / 34%	FEV1/FVC (bronchodilator use not reported)<0.70 and FEV1<80% of predicted present in 16%
Kristoffersen16	63	2000 - 2001	Denmark	48% / n.r.	Post-bronchodilator FEV1/FVC <0.7 present in 10% at baseline, 19% at 4.4 years of follow-up

FEV₁: forced expiratory volume in one second

FVC : forced vital capacity

LLN: lower limit of normal

n.r.: not reported