Table 1.

Results From Meta-Regression of the Intracluster Correlation Coefficient for the Clinical Sign “Trachomatous Inflammation—Follicular” Among Children Aged 1–9 Years in 261 Population-Based Trachoma Prevalence Surveys, Ethiopia, Mozambique, and Nigeria, 2012–2015

Covariate	No. of Surveys	Pooled ρ Estimate a	95% CI	% of Variance Explained b	β c , d	95% CI
Country				58.2
Ethiopia	162	0.100	0.077, 0.128		1.000	Referent
Mozambique	44	0.032	0.023, 0.045		0.471	0.348, 0.638
Nigeria	55	0.010	0.008, 0.012		0.789	0.273, 2.281
No. of children examined per cluster				44.7
15–29	36	0.097	0.071, 0.132		1.000	Referent
30–49	172	0.071	0.050, 0.100		0.882	0.658, 1.181
50–79	34	0.016	0.010, 0.024		0.518	0.332, 0.809
≥80	19	0.005	0.003, 0.008		0.212	0.096, 0.470
TFe prevalence, %				36.2
<5.0	56	0.015	0.011, 0.020		1.000	Referent
5.0–9.9	56	0.033	0.023, 0.048		1.638	1.230, 2.181
10.0–29.9	87	0.080	0.057, 0.114		2.392	1.816, 3.150
≥30.0	62	0.111	0.077, 0.162		2.493	1.810, 3.432
No. of recordersf				48.7
<5	53	0.009	0.007, 0.012		1.000	Referent
5–9	43	0.057	0.039, 0.083		2.335	0.834, 6.534
10–19	149	0.082	0.061, 0.109		2.740	0.945, 7.944
≥20	16	0.106	0.063, 0.178		2.727	0.891, 8.343
No. of children examined per household				30.1
1.0–1.9	105	0.081	0.066, 0.099		1.000	Referent
2.0–2.9	130	0.051	0.038, 0.067		0.786	0.627, 0.986
3.0–3.9	19	0.006	0.003, 0.010		0.721	0.387, 1.339
≥4.0	7	0.010	0.004, 0.023		1.710	0.677, 4.316
Quartile of distance between clustersg, km				13.8
1	65	0.023	0.017, 0.030		1.000	Referent
2	66	0.051	0.034, 0.076		0.974	0.734, 1.289
3	65	0.084	0.056, 0.127		1.059	0.785, 1.430
4	65	0.065	0.043, 0.098		0.963	0.700, 1.324

Abbreviations: CI, confidence interval; GPS, Global Positioning System; ICC, intracluster correlation coefficient; TF, trachomatous inflammation—follicular.

^aPooled estimate of the ICC.

^bProportion of the variability between survey ICC estimates explained by each covariate on the natural logarithmic scale (P < 0.0001 for all variables).

^cExponentiated meta-regression coefficient.

^dFull meta-regression model adjusting for country, number of children examined per cluster, and prevalence of TF in children aged 1–9 years (P < 0.0001). 69.2% of the variance in the ICC was explained by the full model.

^eTF in children aged 1–9 years, the primary clinical sign associated with ocular Chlamydia trachomatis infection used to guide intervention programs under current World Health Organization guidelines (23).

^fEstimated as the number of unique recorder identification codes used in the survey.

^gEstimated as the square root of the variance of the distance of survey clusters from the geometric center of the GPS coordinates of all survey clusters, converted to kilometers and accounting for latitude.