3. Summary of studies reporting mortality.
| Study | Outcome reported | Mortality in CS treatment group | Mortality in group not treated with CS | Reported unadjusted risk of mortality | Reported adjusted risk of mortality | Variables included in model for adjusted estimates |
| Balaganesakumar 2013 | Mortality | 50/70 (71.4) | 20/210 (9.5) | OR 23.8 (95% CI 11.3 to 50.8) | Not reported | — |
| Brun‐Buisson 2011 | In‐hospital mortality | 28/83 (33.8) | 21/125 (16.8) | HR 2.39 (95% CI 1.32 to 4.31) | aHR 2.59 (95% CI 1.42 to 4.73) | Immunosuppression, disease severity (SAPS III), vasopressor use |
| Cao 2016 | 30‐day mortality (also adjusted estimates provided for 60‐day mortality | 81/204 (39.7) | 11/84 (13.1) | Not reported | aHR 1.81 (95% CI 0.88 to 3.74) | Age, underlying comorbidities, laboratory findings, PaO2/FiO2, shock, antibiotics, NAI treatment |
| Chawla 2013 | Mortality | 9/38 (23.7) | 1/39 (2.6) | OR 11.8 (95% CI 1.4 to 98.4) | Not reported | — |
| Delaney 2016 | In‐hospital mortality | 70/280 (25.0) | 51/324 (15.7) | OR 1.82 (1.21 to 2.74) | aOR 1.85 (95% CI 1.12 to 3.04) | Age, sex, disease severity, comorbid illness, bacterial co‐infection at admission |
| Huang 2017 | Mortality | 9/29 (31.0) | 5/19 (26.3) | OR 1.26 (95% CI 0.35 to 4.57) | Not reported | N/A |
| Kim 2011 | 90‐day mortality (also unadjusted estimates provided for 14‐day and 30‐day mortality) | 62/107 (57.9) | 37/138 (26.8) | OR 3.76 (95% CI 2.19 to 6.44) | aOR 2.20 (95% CI 1.03 to 4.71) | Age, disease severity (SOFA), MV, lymphocyte count, propensity score) |
| Kinikar 2012 | In‐hospital mortality | 9/21 (42.8) | 6/71 (8.4) | OR 8.12 (95% CI 2.44 to 27.05) | Not reported | N/A |
| Lee 2015 | 30‐day mortality (also adjusted estimates provided for 60‐day mortality) | 60/600 (10.0) | 96/2049 (4.7) | Not reported | aHR 1.73 (95% CI 1.14 to 2.62) | Age, sex, NAI propensity, bacterial superinfection, statins, influenza subtype |
| Li 2012 | Mortality | 6/27 (22.2) | 1/19 (5.2) | OR 5.14 (95% CI 0.56 to 46.82) | Not reported | N/A |
| Li 2017 | 30‐day mortality | 232/1055 (22.0) | 74/1086 (6.8) | OR 3.86 (95% CI 2.92 to 5.09) | aHR 0.80 (95% CI 0.56 to 1.15) | Age, underlying comorbidities, disease severity, NAI treatment, propensity scores |
| Liem 2009 | In‐hospital mortality | 17/29 (58.6) | 9/38 (23.7) | OR 4.25 (95% CI 1.48 to 12.22) | aOR 4.11 (95% CI 1.14 to 14.83) | Neutropenia as surrogate for severity |
| Linko 2011 | In‐hospital mortality | 8/72 (11.1) | 2/60 (3.3) | OR 3.63 (95% CI 0.74 to 17.77) | aOR 3.3 (95% CI 0.5 to 23.4) | Disease severity (SAPS II) |
| Mady 2012 | In‐hospital mortality | 20/43 (46.5) | 10/43 (23.2) | OR 2.87 (95% CI 1.14 to 7.25) | Not reported | N/A |
| Moreno 2018 | ICU mortality | 166/604 (27.5) | 234/1242 (18.8) | OR 1.6 (95% CI 1.3 to 2.0) | aHR 1.32 (95% CI 1.08 to 1.60) | Propensity matched, APACHE II, gap ICU, number infiltrates on chest x‐ray, laboratory parameters, comorbidities, pregnancy, MV, non‐invasive MV failure, ventilator‐associated pneumonia |
| Patel 2013 | Mortality | 11/39 (28.2) | 3/24 (12.5) | OR 2.75 (95% CI 0.68 to 11.1) | Not reported | — |
| Sertogullarindan 2011 | Mortality | 4/7 (57.1) | 5/13 (34.5) | OR 2.13 (95% CI 0.33 to 13.81) | Not reported | N/A |
| Sheu 2017 | Mortality | Not reported | Not reported | Not reported | aHR 1.81 (95% CI 1.04 to 3.14) | Age, sex, APACHE II score, ARDS severity |
| Viasus 2011 | Mortality (primary outcome was "severe disease" = ICU admission/death) | 3/37 (8.1) | 4/129 (3.1) | OR 2.76 (95% CI 0.59 to 12.92) | Not reported | N/A |
| Xi 2010 | In‐hospital mortality | 17/52 (32.7) | 10/103 (9.7) | OR 4.52 (95% CI 1.89 to 10.81) | aOR 3.67 (95% CI 0.99 to 13.64) | Ethnicity, comorbid illness, symptoms at onset, laboratory tests |
| Wirz 2016 | 30‐day mortality | 1/11 (9.1) | 1/13 (7.7) | OR 1.2 (95% CI 0.07 to 21.72) | aOR 0.13 (95% CI not reported) | Age, Pneumonia Severity Index, comorbidities |
| Yu 2011a | Mortality | 14/54 (25.9) | 4/74 (5.4) | OR 6.12 (95% CI 1.89 to 19.88) | Not reported | N/A |
aHR: adjusted hazard ratio aOR: adjusted odds ratio APACHE: Acute Physiology and Chronic Health Evaluation ARDS: adult respiratory distress syndrome CI: confidence interval CS: corticosteroid HR: hazard ratio ICU: intensive care unit MV: mechanical ventilation NAI: neuraminidase inhibitor OR: odds ratio PaO2/FiO2: ratio of partial pressure of oxygen in arterial blood to inspired fraction of oxygen SAPS: Simplified Acute Physiology Score SOFA: Sequential Organ Failure Assessment