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

Abstract Introduction In this study, we determined: (1) the utility of an untimed sample of urine protein/creatinine ratio (PCR) as a screening test for proteinuria, (2) its ability to accurately measure proteinuria, and (3) cutoff values for PCR predicting protein content in a 24-h urine collection sample (24hP) of 0.5, 1.0, and 2.0 g/day. Methods Analysis was performed on data from a single lupus cohort (2008–2014). Proteinuria was measured in a 24hP and with PCR. On the basis of 24hP, samples were divided into 4 groups: group 1, <0.5 g/day; group 2, 0.5–0.99 g/day; group 3, 1–1.99 g/day; and group 4, ≥2 g/day. To determine the validity of PCR in screening for proteinuria, the Pearson correlation coefficient was determined for the urine samples with normal PCR (<0.05 g/mmol) and normal 24hP (<0.5 g/day). The sensitivity, specificity, positive predictive value (PPV), and negative predictive value (NPV) of PCR were calculated. To determine the ability of PCR to accurately measure the level of proteinuria, in addition to the correlation between 24hP and PCR, agreement was determined by intraclass correlation coefficient, concordance correlation coefficient, and Bland-Altman plot between 24hP/24hC and PCR. The best cutoffs for PCR predicting a 24hP of 0.5, 1.0, and 2.0 g/day were determined with the receiver operating characteristic curve. Results The correlation of the samples with normal PCR as well as 24hP (n = 552) was 0.29 (p < 0.0001). PCR sensitivity and specificity against 24hP were 91 % and 83 %, respectively. The PPV was 82.5 %, and the NPV was 91.4 %. The correlation for all samples (n = 1233) was high, but low to moderate for groups 1, 2, 3, and 4. The agreement for all samples was appropriate but poor for groups 1, 2, 3, and 4. PCR cutoffs for 24hP of 0.5, 1.0, and 2.0 g/day were 0.08, 0.16, and 0.35 g/mmol, respectively. Conclusions PCR can be used as a screening test for proteinuria, and the best cutoff value to predict a 24hP of 0.5 g/day is 0.08 g/mmol (800 mg/g). The accurate level of proteinuria should be measured by the gold standard test, 24hP

Prevalence and associated factors of resting electrocardiogram abnormalities among systemic lupus erythematosus patients without cardiovascular disease

Abstract Background Electrocardiogram (ECG) cardiovascular disease (CVD) abnormalities (ECG-CVD) are predictive of subsequent CVD events in the general population. Systemic lupus erythematosus (SLE) patients are vulnerable to CVD. We aimed to determine the prevalence of ECG-CVD in SLE patients and to examine the risk factors associated with ECG-CVD. Methods A 12-lead resting supine ECG was performed on consecutive adult patients attending the clinic. One cardiologist interpreted the ECGs. ECG-CVD were defined as the presence of one or more of the following 4 elements (ECG-4): ST-segment and/or T-wave abnormalities, left ventricular hypertrophy (LVH), left axis deviation (LAD), left bundle branch block (LBBB) and right bundle branch block (RBBB). ECG-5 included the same elements as ECG-4 and the Q-wave. Repeated measurement data were created and the associations between ECG-4/ECG-5 and demographics were evaluated with univariate and multivariate Cox regression models. Results Of 487 SLE patients, 104 (21.4%) and 118 (24.2%) patients had one or more of the ECG-4 and ECG-5 elements, respectively. A higher prevalence of ECG-CVD was found in patients with a longer SLE disease duration, and the burden of ECG-CVD elements increased with age. Increased age, active SLE disease, and damage were associated with ECG4 and ECG-5, while treatment of hyperlipidemia was protective. Conclusion A high prevalence of ECG-4 (21.4%) and ECG-5 (24.2%) was found in this SLE cohort. Controlling SLE disease activity is important since it was associated with ECG-4 and ECG-5. Early identification of ECG-4 and ECG-5 in SLE patients might allow for better stratification and risk management