Table 2

Pooled RRs for adverse cardiovascular outcomes by subgroups of study variable

SubgroupsC-reactive protein groups
≤3.0 mg/l3.1∼10.0 mg/l>10.0 mg/l
ReferentNRR (95% CI)NRR (95% CI)
Overall1.00125–7 9–11 14 16 19 21 22 241.40 (1.18 to 1.67)116 7 9–11 14 15 19 21 22 242.18 (1.77 to 2.68)
Outcome
 Heart failure1.0036 11 211.72 (1.17 to 2.55)36 11 212.89 (2.07 to 4.02)
 Cardiac death1.0037 14 241.19 (0.80 to 1.77)37 14 242.10 (1.50 to 2.92)
 All-cause death1.0095–7 9 11 14 19 21 241.49 (1.21 to 1.84)85–7 9 11 14 21 242.50 (2.12 to 2.96)
 p for heterogeneity0.420.41
Time for blood samples obtained from the onset of symptoms
 ≤24 h1.0095–7 10 11 14 16 21 241.39 (1.11 to 1.74)76 7 10 11 14 21 242.34 (1.92 to 2.85)
 >24 h or on admission1.0039 19 221.43 (1.08 to 1.88)49 15 19 221.92 (1.26 to 2.95)
 p for heterogeneity0.860.42
Follow-up year
 >1 year1.0069–11 14 21 241.32 (1.04 to 1.69)79–11 14 15 21 242.18 (1.77 to 2.69)
 ≤1 year1.0065–7 16 19 221.49 (1.16 to 1.91)46 7 19 222.19 (1.36 to 3.52)
 p for heterogeneity0.510.99
Region
 Europe1.0077 9 10 14 16 22 241.26 (1.01 to 1.57)77 9 10 14 15 22 241.83 (1.46 to 2.29)
 Non-Europe1.0055 6 11 19 211.67 (1.26 to 2.21)46 11 19 212.81 (2.25 to 3.52)
 p for heterogeneity0.120.01
Confounder adjustments*
 Unadjusted1.0066 10 11 14 21 241.54 (1.19 to 1.99)76 10 11 14 15 21 243.53 (2.54 to 4.91)
 Adjusted1.0066 10 11 14 21 241.36 (1.05 to 1.76)76 10 11 14 15 21 242.31 (1.78 to 3.00)
 p for heterogeneity0.520.05
Mean age
 <65 y1.0065 7 11 19 21 241.55 (1.20 to 2.00)67 11 15 19 21 242.23 (1.68 to 2.98)
 ≥65 y1.0076 9–11 14 16 221.33 (1.08 to 1.64)66 9–11 14 222.15 (1.65 to 2.80)
 p for heterogeneity0.370.85
Study quality
 High1.0066 7 10 14 21 241.21 (0.90 to 1.62)66 7 10 14 21 242.31 (1.84 to 2.91)
 Low1.0065 9 11 16 19 221.52 (1.23 to 1.89)59 11 15 19 222.01 (1.43 to 2.83)
 p for heterogeneity0.210.51
Original study design
 Cohort1.0085–7 7 9–11 21 241.42 (1.13 to 1.78)86 7 9–11 15 21 242.18 (1.74 to 2.72)
 Trial1.00414 16 19 221.39 (1.06 to 1.82)314 19 222.13 (1.24 to 3.67)
 p for heterogeneity0.910.94
  • * The results were from the articles that provided both crude and adjusted RRs (95% CIs).

  • High quality was defined as articles that met four or more of the six quality criteria. Low quality was defined as articles that met three or fewer of the six quality criteria.

  • N, number of the study.