Table 3.

Scoring system 1: LN-Code

Patient characteristic All patients are required to have at least one diagnosis code (ICD9 or ICD10) for SLE	Points (add unless stated)	Total score	Predicted probability
One diagnosis code (ICD10) for LN Or Two or more diagnosis codes (ICD9 or ICD10) for LN	35	<80	<50%
	115	80–110	50–60%
One diagnosis code for acute or chronic kidney disease or proteinuria Or Two or more diagnosis codes for acute or chronic kidney disease or proteinuria	70	110–140	60–70%
	95	140–175	70–80%
Any use of mycophenolate mofetil or mycophenolic acid	45	175–230	80–90%
Age (in years) at first SLE diagnosis code	Subtract age	>230	>90%

Diagnosis codes for LN included ICD10 codes: M32.14 or M32.15, or ICD9 code 710.0 in combination with ICD9 codes: 583.81, 581.81 or 583.89. Diagnosis codes for acute or chronic kidney disease or proteinuria included ICD10 codes: N00–N08, N17–N19 and R80, or ICD9 codes: 580–586 and 791.0.

ICD, International Classification of Diseases; LN, lupus nephritis.