TABLE 1.

Limits on search date and the number of studies included per meta-analysis, and the resulting studies and metaanalyses lost

Years searched	Median number of studies per meta-analysis (IQR)	Number of studies included (% of studies lost)	Number of meta-analyses included (% of meta-analyses lost)
1	4 (3–9)	1383 (89.2)	188 (77.8)
2	5 (3–9)	2359 (81.5)	321 (62.1)
3	5 (3–8)	3295 (74.2)	450 (46.8)
4	5 (3–9)	4226 (66.9)	537 (36.5)
5	6 (3–10)	5139 (59.8)	595 (29.7)
10	7 (4–12)	8324 (34.9)	766 (9.5)
15	8 (5–14)	10,120 (20.8)	813 (3.9)
20	8 (6–15)	11,233 (12.1)	830 (1.9)
25	9 (6–16)	11,822 (7.6)	838 (1.0)
30	9 (6–16)	12,068 (5.6)	843 (0.4)
35	9 (6–16)	12,200 (4.6)	844 (0.2)
40	9 (6–16)	12,281 (3.9)	846 (0.0)
Full meta-analysis	9 (6–17)	12,784	846

Abbreviation: IQR, interquartile range.