Utility of untimed single urine protein/creatinine ratio as a substitute for 24-h proteinuria for assessment of proteinuria in systemic lupus erythematosus

Table 2 Results of correlations between 24hP and PCR and agreement between 24hP/24hC and PCR

	Correlation	Interpretation^a	ICC (2, k)	Interpretation^b	CCC	Interpretation^c
	p value	Interpretation^a	95 % CI	Interpretation^b	95 % CI	Interpretation^c
All samples	0.79	High	0.87	Appropriate	0.85	Poor
All samples	<0.0001	High	0.83–0.91	Appropriate	0.83–0.87	Poor
24hP	0.4	Low	0.52	Poor	0.62	Poor
<0.5 g/day	<0.0001	Low	0.50–0.53	Poor	0.56–0.67	Poor
24hP	0.2	Negligible	0.57	Poor	0.34	Poor
0.5–0.99 g/day	0.0007	Negligible	0.55–0.58	Poor	0.24–0.46	Poor
24hP	0.3	Low	0.73	Poor	0.55	Poor
1–1.99 g/day	0.001	Low	0.70–0.76	Poor	0.43–0.68	Poor
24hP	0.6	Moderate	0.77	Poor	0.44	Poor
≥2.0 g/day	0.0001	Moderate	0.70–0.83	Poor	0.35–0.53	Poor

CCC concordance correlation coefficient, CI confidence interval, 24hC measured creatinine content in a 24-h urine sample collection, 24hP protein content in a 24-h urine collection sample, ICC intraclass correlation coefficient
The ratio of the protein content and the creatinine content in a 24-h urine collection sample (24hP/24hC) was calculated by dividing 24hP (g/day) by creatinine content (mmol/day) reported in the results of the same 24 h urine sample
^aCorrelation: negligible (r = 0.00–0.29), low (r = 0.3–0.49), moderate (r = 0.5–0.7), high (r = 0.7–0.9), very high (r = 0.9–0.99)
^bMeasure of agreement: ICC (2, k) ≥0.85 = good reliability (agreement)
^cMeasure of agreement: CCC <0.9 = poor agreement

ISSN: 1478-6362