Table 1 Characteristics of included studies, patient populations, topic and results of risk of bias assessment
From: Seasonal influenza vaccination in patients with COPD: a systematic literature review
Reference (Country) | Study design (population) | Influenza season (setting) | Mean (SD) Agea | Gender, % malea | N total | Outcome | Potential bias identified & expected impact (Quality assessmentb) |
|---|---|---|---|---|---|---|---|
Randomised controlled trials | |||||||
Chuaychoo et al., 2010 [31] (Thailand) | Open label RCT (Patients with confirmed COPD) | 2006–2007 (1 hospital COPD clinic) | 73 (9) | 90.7% | 75 | Immunogenicity Safety | No placebo-controlled group; open-label design; self-reported safety outcomes (LOW) |
Gorse et al., 2004c [32] (US) | Placebo-controlled RCT (Patients ≥ 50 years with confirmed COPD) | 1998–1999 (20 Veterans affairs medical centres) | 67.9 (8.5)/67.8 (8.2) | 98.0/98.4% | 2,215 | Immunogenicity | Serum titres tested in 61 subject; no placebo-controlled/unvaccinated group (ACCEPTABLE) |
Gorse et al., 2003c [39] | Â | Â | 2,215 | Safety | Self-reported safety outcomes (ACCEPTABLE) | ||
Kositanont et al., 2004d [40] (Thailand) | Placebo-controlled RCT (2 doses 1 month apart) (Patients with confirmed COPD) | 1997–1998 (1 hospital COPD clinic) | 67.6 (8)/69.1 (7) | 95.2/93.7% | 123 | Immunogenicity Efficacy | Self-reported safety outcomes (ACCEPTABLE) |
Wongsurakiat et al. 2004ad[35] | Â | Â | Â | 125 | Immunogenicity Efficacy | Â | |
Wongsurakiat et al., 2004bd[38] | Â | Â | Â | 125 | Safety | Â | |
Gorse et al., 1997 [33] (US) | RCT (Outpatients with confirmed COPD) | (Veterans affairs medical centres) | 65.2 (2.1) | 100% | 29 | Immunogenicity Safety | Small sample size; no estimate of study power; limited information on patient characteristics; males only (LOW) |
Observational studies | |||||||
Nath et al., 2014 [34] (Australia) | Prospective cohort study (Patients with confirmed COPD) | 2010 (outpatient clinics 1 hospital) | 66.2 (11.0)/54.3 (14.5) | 65.0/57.1% | 34 | Immunogenicity | Small sample size; no estimate of study power; significant differences between groups at baseline; serological response to only one vaccine strain (LOW) |
Chen et al., 2013e [45] (Taiwan) | Retrospective, Database study (Patients ≥ 55 years with COPD diagnosed using ICD-9 codes) | 2000–2007 (Taiwan National Health Insurance Research Dataset) | - | 58.9/53.4% | 25,609 | Effectiveness | Retrospective design; no estimate of study power (ACCEPTABLE) |
Sung et al., 2014e [46] | ≥55 | 58.7/60.8% | 7,722 | Effectiveness | Retrospective design; estimate of study power (ACCEPTABLE) | ||
Menon et al., 2008 [43] (India) | Self-controlled case series (Male patients with confirmed COPD) | 2004–2006 (outpatient department 1 hospital) | 64.8 (8) | 100% | 87 | Effectiveness | Small sample size; no estimate of study power; males only; comparison of different influenza seasons (LOW) |
Schembri et al., 2009 [42] (UK) | Retrospective, database study (Patients ≥ 40 year registered in the data base with COPD) | 1988–2006 (The Health Improvement Network) | - | 42.4/42.8% | 40,741 | Effectiveness | Retrospective design; no estimate of study power (ACCEPTABLE) |
Vila-Córcoles et al., 2008 [41] (Spain) | Prospective cohort study (Community-dwelling ≥65 years olds registered with COPD in clinic record) | 2002–2005 (8 urban health centres) | 74.1 (6.8)/76.3 (6.9) | 73.7/74.5% | 1,298 | Effectiveness | Significant differences between groups at baseline; no estimate of study power (ACCEPTABLE) |
Ting et al., 2011 [36] (UK) | Retrospective matched cohort study (Patients with confirmed COPD) | 2005 (6 general practices) | 68 (37–89) | 64.8% | 586 | Safety | Retrospective design; sample size calculations performed but details not presented; limited information on patient characteristics; matched pairs of patients, but no results of matching (LOW) |
Montserrat-Capdevila et al., 2014 [44] (Spain) | Retrospective cohort study (Patients registered with confirmed COPD) | 2001–2002 (1 hospital) | 75.6 (11.7)/57.1 (18.2) | 65.2/60.5% | 1,323 | Effectiveness | Retrospective design; no estimate of study power (ACCEPTABLE) |
Tata et al., 2003 [37] (UK) | Database study with self-controlled case series (Random sample of patients with COPD using OXMIS and READ codes) | 1991–1994 (Clinical Practice Research Datalink, previously General Practice Research Database) | 65–79 | 63% | 2,100 | Safety | Retrospective design; limited information on patient characteristics (ACCEPTABLE) |
Wang et al., 2003 [12] (Taiwan) | Retrospective population-based cohort study (>65Â years old patients with COPD identified using ICD-9 mortality codes) | 2001 | No data for patients with COPD | 102,698 elderly | Effectiveness | Retrospective database design; no estimate of study power; COPD identified from mortality ICD-9 codes; Reason for risk status not known; limited information on patient characteristics (LOW) | |