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Table 1 Characteristics of included studies

From: Long-acting beta-agonists plus inhaled corticosteroids safety: a systematic review and meta-analysis of non-randomized studies

Author and publication year Study design Sample size (n) Age (years) Administration mode Follow-up period Ascertainment of asthma Outcomes Endpoint measure
        Specific Combined  
Wells et al., 2012 [22] RC 1,828 12-56 Single inhaler *2.1(2.0) years Asthma treatment ------- 1- Asthma-related hospitalization OR asthma-related ED visit OR Systemic Corticosteroid use aHR
Jacobs et al., 2012 [23] C-C 181 4-18 Not stated NA Clinical diagnosis 1- ICU admission ------- aOR OR
2- Deaths
3- Intubation
4- Positive air pressure use
Stanford et al., 2012 [24] RC 10,837 65-79 Single inhaler 12 months Claims for asthma 1- Asthma-related hospitalization 1- Asthma-related hospitalization OR asthma-related ED visits aHR
2- Asthma-related ED visits
3- Systemic Corticosteroid use
Guo et al., 2011 [21] RC 514,216 0-40 Single & Separate inhalers - Claims for asthma ------- 1- Asthma-related hospitalization OR asthma-related ED visits OR Asthma-related intubations aHR
Stanford et al., 2010 [25] RC 50,428 > 4 Single inhaler *290.4 (102.8) days Claims for asthma 1- Asthma-related hospitalization 1- Asthma-related hospitalization OR asthma-related ED visits aHR
2- Asthma-related ED visits
Hagiwara et al., 2010 [26] RC 894 12-64 Single inhaler 3-12 months Claims for asthma 1-Asthma-related hospitalization 1- Hospitalization OR ED visits aOR
2-Asthma-related ED visits 2- Hospitalization OR ED visits OR Systemic Corticosteroid use
3-Use of SABAs
Delea et al., 2010 [27] RC 1,744 > 12 Single inhaler 3-12 months Claims for asthma 1- ED visits 1- ED visits OR Hospitalization aOR
2- ED visits OR hospitalization OR Systemic Corticosteroid use
de Vries et al., 2010 [28] RC 467,639 >18 Not stated 5 years Claims for asthma 1- All mortality; ------- aRR
2- Asthma-related mortality
3-Asthma-related hospitalization
4-GP visits for exacerbation
Lee et al., 2010 [29] RC 28,074 18-56 Single & Separate inhalers 12 months Claims for asthma 1- Asthma-related hospitalization ------- OR
2-Asthma-related ED visits
3-Systemic Corticosteroid use
4- SABAs use
Thomas et al., 2009 [30] RC 64,348 10-58 Single & Separate inhalers 12 months Claims for asthma and asthma treatment 1- Respiratory Hospitalization 1- Asthma-related hospitalization OR asthma-related ED visits OR > 2 prescription of Systemic Corticosteroid uses OR SABA prescription aOR
2- Systemic Corticosteroid use
3- SABAs use
Stanford et al., 2008 [31] RC 58,270 > 12 Single inhaler 12 months Claim for asthma 1-Asthma-related Hospitalization 1- Asthma-related ED visits OR asthma-related Hospitalization aOR
2- Asthma-related ED visits aHR
Campbell et al., 2008 [32] PC 684 > 18 Single inhaler 24 months Severe asthma ------- 1- Asthma-related hospitalization OR asthma-related ED visit OR Systemic Corticosteroid use aOR OR
Colice et al., 2008 [33] RC 1,283 6-64 Not stated 12 months Claims for asthma 1- Asthma-related hospitalization ------- OR
2- Asthma-related ED visits
Delea et al., 2008 [34] RC 2,269 > 5 Single & Separate inhalers 12 months Claims for asthma 1- Asthma-related hospitalization 1- Asthma-related hospitalization OR ED visits OR Systemic Corticosteroid use OR alternative study medication aOR
2- Asthma-related ED visits 2- Asthma-related hospitalizations OR ED visits OR oral corticosteroid
3- Oral corticosteroids use 3- Asthma-related hospitalization OR ED visits hospitalization
Friedman et al., 2007 [35] RC 5,503 12-65 Single inhaler 12 months Claims for asthma 1-Asthma-related hospitalization ------- aOR
2-Asthma-related ED visits
3- Any ED visits
Zhang et al., 2007 [36] RC 2,596 15-55 Single & Separate inhalers 12 months Claims for asthma 1- Oral corticosteroid use 1- Asthma-related hospitalization OR asthma-related ED visits OR
2- SABA use
Stempel et al., 2006 [37] RC 9,192 4-17 Single inhaler 12 months Claims for asthma 1- SABA use 1- Asthma-related hospitalization OR asthma-related ED visit aRR
2-Corticosteroids use
O’Connor et al., 2005 [38] RC 2,414 > 15 Single & Separate inhalers 12 months Claims for asthma ------- 1- Asthma-related hospitalization OR ED visits aOR aHR
Nguyen et al., 2005 [20] B-A 50 4-17 Single inhaler 12 months Enrolled patients 1- Asthma-related hospitalization ------- aRR
        2- Asthma-related ED visits   
  1. RC: Retrospective Cohort; C-C: Case-control study; PC: Prospective cohort; B-A: Before-after study; * = Mean (SD); SABA = Short- Acting Beta-Agonist; ED = Emergency Department; HR = Hazard Ratio; OR = Odds Ratio; aHR = Adjusted HR; aOR = Adjusted OR.