Table 1 Characteristics of included studies

Lee T-M, et al., Taiwan, 2008[19]

Randomized, double-blinded, placebo-controlled trial

To investigate whether pravastatin administration is effective in improving exercise capacity in patients with COPD, and whether baseline or serial changes in hs-CRP over time are associated with corresponding changes in exercise capacity.

n = 62 patients with clinically stable COPD, received pravastatin (40 mg/day) over a period of 6 months (randomly assigned, double blind).

n = 63 patients with clinically stable COPD, received placebo over a period of 6 months (randomly assigned, double blind).

Exercise capacity

CRP/IL-6

Secondary outcome measurements:

Lung function

Borg dyspnea score after exercise tests

Blamoun AI et al, USA, 2008 [27]

Cohort study

To assess the rate of COPD exacerbations and intubations in COPD patients taking statins

n = 90 patients with primary or secondary diagnosis of COPD who were taking statins at the time of hospital admission and during the 1-year follow-up

n = 95 patients with primary or secondary diagnosis of COPD who were not taking statins at the time of hospital admission and during the 1-year follow-up

COPD exacerbations

Intubations secondary to COPD exacerbation

Van Gestel YR et al., Netherlands, 2008 [21]

Cohort study

To examine the relation between statins and mortality (within 30 days and 10 years) in a group of patients who underwent surgery for peripheral arterial disease and compare results in those with versus without associated COPD

COPD group:

n = 330 COPD patients who underwent elective vascular surgery and who did use statins

COPD group:

n = 980 COPD patients who underwent elective vascular surgery and who did use statins

All-cause mortality, short- and long-term (within 30 days and 10 years of follow-up respectively)

Søyseth V et al., Norway, 2007[22]

Cohort study

To determine whether statins alone or in combination with inhaled steroids improve survival after COPD exacerbation

n = 118

patients with a diagnosis of COPD exacerbation at hospital discharge who were taking statins at the time of discharge

n = 736

patients with a diagnosis of COPD exacerbation at hospital discharge who were not taking statins at the time of discharge

All-cause mortality

Frost FJ et al., USA, 2007 [20]

Cohort study, and separate case-control studies (for influenza and COPD deaths)

To assess whether statin users have reduced mortality risks from influenza and COPD

Cohort study:

n = 19,058; patients with statin exposure

Case control study:

n = 207; COPD deaths (in hospital)

Cohort study:

n = 57,174; patients with no history of statin therapy

Case-control study:

n = 9,622; surviving patients with either an inpatient or outpatient diagnosis of COPD

Mortality from COPD (and influenza, not included in this review)

Keddissi JI, et al., USA, 2007 [26]

Cohort study

To assess the ability of statins to preserve lung function in current and former smokers and to reduce the incidence of respiratory-related urgent care

n = 215; statin users who were smokers or ex-smokers and had abnormal baseline spirometry (majority with obstructive spirometry findings, but restrictive findings also included).

n = 203; non-statin users who were smokers or ex-smokers and had abnormal baseline spirometry (obstruction or restriction)

Lung function (annual decline in FEV1 and FVC)

Respiratory-related ED-visits and hospitalizations

Mancini GB et al., Canada, 2006 [25]

Nested case-control study (time-matched)

To determine if statins, angiotensin-converting enzyme-inhibitors and angiotensin receptor blockers reduce total mortality, COPD hospitalisations and myocardial infarctions in COPD patients

Two distinct COPD cohorts:

1) n = 2983 (sum of cases analysed for different endpoints, n = 3231 when steroid users included), high cardiovascular risk cohort (COPD patients having undergone coronary revascularization)

2) n = 7617 (sum of cases analysed for different endpoints, n = 8240 when steroid users included), low cardiovascular risk cohort (COPD patients without previous myocardial infarction and newly treated with nonsteroidal anti-inflammatory drug)

from same databases as study population, matched for age and year of cohort entry and still at risk of the event (endpoint)

n = 59,170 for cohort 1 (sum of controls for different endpoints, n = 64,185 including steroid users)

n = 152,177 for cohort 2 (sum of controls for different endpoints, n = 164,672 including steroid users)

COPD hospitalizations

Myocardial infarction

All-cause mortality

Ishida W, et al., Japan, 2007 [23]

Ecological analysis

To assess effects of statin use on mortality from major causes of death (cardiovascular diseases, COPD, pneumonia etc.)

COPD deaths in the >65 yrs old population in each of the 47 prefectures of Japan

No control

Mortality from COPD (and other major diseases), related to statin sales in the same area