Table 3.

American Indian and Alaska Native proportion estimates overall, by phase, multi-institutional status, tier assessment, masking, and year.

	Frequency (%), studies	Total number of participants	Estimated proportion (95% CI)	P-value compared to reference category (*)	P-value compared to 2010 Census proportion (1.10%)	$I^2$(%)
American Indian and Alaska Native
Overall	–	–	0.19% (0.15–0.23)	–	< 0.0001	78.5%
Phase
II*	1094 (68.9%)	103,813	0.13% (0.10–0.18)	–	< .0001	78.2%
III	495 (31.2%)	220,155	0.30% (0.23–0.38)	< .0001	< .0001
Institution status
Single*	682 (42.9%)	102,520	0.09% (0.05–0.14)	–	< .0001	77.9%
Multi-institutional	907 (57.1%)	221,448	0.26% (0.21–0.31)	< .0001	< .0001
Tier assessment
1*	824 (51.9%)	57,943	0.09% (0.05–0.13)	–	< .0001	78.0%
2	765 (48.1%)	266,025	0.29% (0.23–0.35)	< .0001	< .0001
Masking
No masking*	341 (21.5%)	55,000	0.20% (0.12–0.29)	–	< .0001	78.0%
Single	107 (6.73%)	22,081	0.13% (0.03–0.27)	0.357	< .0001
Double	389 (24.5%)	79,017	0.17% (0.11–0.25)	0.645	< .0001
Triple	287 (18.1%)	72,527	0.22% (0.13–0.32)	0.746	< .0001
Quadruple	465 (29.3%)	95,343	0.20% (0.14–0.28)	0.981	< .0001
Study start year
2008*	121 (7.61%)	35,685	0.13% (0.04–0.26)	–	< .0001	77.5%
2009	156 (9.82%)	30,239	0.27% (0.15–0.43)	0.135	< .0001
2010	134 (8.43%)	45,381	0.22% (0.10–0.38)	0.337	< .0001
2011	145 (9.13%)	17,765	0.14% (0.05–0.27)	0.891	< .0001
2012	159 (10.0%)	29,668	0.24% (0.12–0.39)	0.219	< .0001
2013	189 (11.9%)	32,347	0.11% (0.04–0.21)	0.639	< .0001
2014	169 (10.6%)	25,349	0.17% (0.08–0.30)	0.616	< .0001
2015	177 (11.1%)	29,085	0.31% (0.18–0.48)	0.0525	< .0001
2016	150 (9.44%)	41,432	0.19% (0.09–0.32)	0.490	< .0001
2017	128 (8.06%)	23,619	0.14% (0.05–0.29)	0.868	< .0001
2018	47 (2.96%)	10,243	0.20% (0.04–0.49)	0.545	< .0001
2019	14 (0.88%)	3155	0.20% (0.00–0.87)	0.737	0.0156