First author Location of patients Study design Comparison Age, year Prevalence of smoking Former smokers Current smokers CDC report [4 ] — R, MC Non-ICU vs. ICU 7162 — 261 (3.6) 165 (2.3) 96 (1.3) Chen Q [10 ] Taizhou, China R, O, SC Nonsevere vs. severe 145 47.5 15 (10.3) — — Feng Y [11 ] Wuhan, Anhui, Shanghai R, O, MC Moderate vs. severe, critical 454 53.0 44 (9.7) — — Goyal P [12 ] Newyork, USA R, MC Non-IMV vs. IMV 393 62.2 20 (5.1) — 20 (5.1) Guan WJ [13 ] 552 hospitals in China R, MC Nonsevere vs. severe 1085 47.0 158 (12.6) 21 (1.9) 137 (12.6) Liu W [14 ] Wuhan, China R, SC Stabilization vs. progression 78 38.0 5 (6.4) — — Mo P [15 ] Wuhan, China R, SC General vs. refractory 155 54.0 6 (3.9) — 6 (3.9) Qi D [16 ] Chongqing, China R, MC Nonsevere vs. severe 267 48.0 53 (19.9) — — Shi Y [ 17 ] Zhejiang, China R Mild vs. severe 487 46.0 40 (8.2) — — Wang R [18 ] Fuyang, China R, SC Noncritical vs. ritical 125 49.4 16 (12.8) — 16 (12.8) Wan S [19 ] Chongqing, China R, SC Mild vs. severe 135 47.0 9 (6.7) — 9 (6.7) Yang X [20 ] Wuhan, China R, O, SC Survivors vs. nonsurvivors 52 51.9 2 (10.0) — — Yu X [21 ] Shanghai, China R, SC Nonsevere vs. severe 333 50.0 26 (7.8) — — Zhang JJ [22 ] Wuhan, China R, SC Nonsevere vs. severe 140 57.0 9 (6.4) 7 (5.0) 2 (1.4) Zhang R [23 ] Wuhan, China R, SC Common type vs. severe 120 45.4 6 (5.0) — 6 (5.0) Zhou F [24 ] Wuhan, China R, O, MC Nonsurvivor vs. survivor 191 56.0 11 (6.0) — 11 (6.0)
