Table 4.

Summary of primary and subgroup random effects meta-analysis

SubgroupNumber of studiesOR 95% CII2P
Primary meta analysis190.84 (0.75–0.95)99%<0.01
Study quality
 Moderate140.81 (0.76–0.85)95%<0.01
 Low50.89 (0.63–1.26)96%0.51
Subgroup differences0%0.58
Study design
 RCTs60.83 (0.71–0.97)91%0.02
 Observational130.83 (0.76–0.91)98%<0.01
Subgroup differences0%0.99
Study setting
 Europe90.78 (0.73–0.84)95%<0.05
 North America30.79 (0.49–1.28)68%0.35
 Asia30.97 (0.73–1.28)100%0.81
 South America10.92 (0.81–1.05)
 Australia30.86 (0.76–0.98)0%0.03
Subgroup differences38%0.16
Letter of invitation
 Letter without advance notification90.77 (0.73–0.82)87%<0.01
 Letter with advance notificationa30.89 (0.64–1.23)92%0.47
Subgroup differences0%0.41
Test delivery
 Test mailed90.79 (0.75–0.83)45%<0.01
 Test collected70.83 (0.66–1.05)99%0.13
Subgroup differences0%0.64
Recommendation
 Recommendation provided80.85 (0.68–1.05)99%0.13
 No recommendation provided70.79 (0.76–0.82)45%<0.01
Subgroup differences0%0.54
Screening age range
 40–75140.79 (0.74–0.84)92%<0.01
 50+ (5)50.92 (0.70–1.19)99%0.51
Subgroup differences13%0.28
Number of samples
 1 sample (10)100.84 (0.71–0.98)99%0.03
 2 or more samples (4)40.78 (0.74–0.82)13%<0.01
Subgroup differences0%0.42
Screening reminders
 No reminder provided20.85 (0.75–0.96)73%0.01
 Reminder provided100.81 (0.73–0.89)87%<0.01
Subgroup differences0%0.51

NOTE: Values in bold indicate P < 0.05.

  • aAdvance notification indicates pre-invitation letter, followed by invitation letter.