Table 3.

Participation rate, NCIC^a, uptake, and yield of cascade testing among family members by proband type

	Proband Type
Parameter With 95% CIsb	FHg+	FHg−	P value
Number of probands	52	73	–
Number of family members identified	253	295
Consented	129	75	–
Completed testing	111	63	–
Met criteria as a new case	48	17
Mean number of family members per proband	4.9 (3.9-5.9)	4.0 (3.4-4.7)	.152
Consented	2.5 (1.9-3.1)	1.0 (0.7-1.3)	<.001
Completed testing	2.1 (1.6-2.7)	0.9 (0.6-1.1)	<.001
Met criteria as a new case	0.9 (0.6-1.3)	0.2 (0.1-0.3)	<.001
NCICc	0.92 (0.61-1.27)	0.23 (0.12-0.34)	<.001
Uptake of cascade testingd	43.9% (35.5-52.2)	21.4% (15.8-26.7)	<.001
Yield of cascade testinge	43.2% (33.6-54.2)	27.0% (16.7-38.5)	.032

FH^g+, familial hypercholesterolemia with a pathogenic variant; FH^g−, familial hypercholesterolemia without a pathogenic variant; LDL-C, low-density lipoprotein cholesterol; NCIC, new cases per index case.

^aNew case defined as a family member who completed testing and had a pathogenic variant among relatives of FH^g+ probands or had LDL-C ≥155 mg/dL among relatives of FH^g− probands.

^bCIs were calculated using bootstrapping over 1000 iterations. Each bootstrap sample selected 52 FH^g+ or 73 FH^g− probands (simple random sampling with replacement) and their corresponding family members. Each parameter was calculated separately within each bootstrap sample and the 2.5th and 97.5th percentiles across all bootstrap samples defined the 95% CIs.

^cNCIC was calculated as the number of family members who met criteria as a new case divided by the total number of probands.

^dUptake was defined as the proportion of family members who consented and completed testing among all identified family members.

^eYield was defined as the proportion of family members who met criteria as a new case among family members who consented and completed testing.