Table 1.

Distinct links included in the problem-medication knowledge base. Relationships extracted directly from NDF-RT have a depth equal to zero.

	SNOMED CT Problem “isa” Depth
	0	1	2	3	4	5	6	7	8	9	10	11	12
Distinct Links	44,421	591,014	1,481,766	1,988,527	1,677,023	935,235	350,401	94,406	31,030	23,602	13,753	2,924	342