Table 2

Recruitment and sample size characteristics of the trials included in the review

Characteristic (N=151)n (%)Mean (SD)MedianRange
No. of centres
 18 (5)29 (35)151–274
 2–523 (15)
 6–1021 (14)
 11–2033 (22)
 21–5035 (23)
 51–10022 (15)
 >1005 (3)
 Missing4 (3)
Original target recruitment
 ≤20014 (9)1231 (2946)54590–28 000
 201–40040 (26)
 401–60031 (21)
 601–80015 (10)
 >80050 (33)
 Missing1 (1)
Final target recruitment
 ≤20017 (11)1132 (2926)48044–28 000
 201–40049 (32)
 401–60027 (18)
 601–80013 (9)
 >80045 (30)
Final total recruitment
 ≤20024 (16)1014 (2673)42419–24 510
 201–40048 (32)
 401–60028 (19)
 601–80012 (8)
 >80039 (26)
Final recruitment target achieved
 Yes85 (56)
 No, but with 80% of target119 (79)
 No, <80% of target32 (21)
Timing of primary outcome follow-up (months postrandomisation)
 <1 month27 (18)9 (10)60–48
 1–6 months54 (36)
 6–18 months36 (24)
 >18 months21 (14)
 Missing13 (9)
Timing of final follow-up (months postrandomisation)
 <1 month9 (6)15 (18)120.066–120
 1–6 months20 (13)
 6–18 months84 (56)
 >18 months33 (22)
 Missing5 (3)