Clinicopathological relationship in Colombian patients with lupus nephritis

Background There are several clinical and laboratory features for lupus nephritis diagnosis; however, renal biopsy remains as the gold standard. Different series have tried to establish the relationship between these findings, with conflicting results. Objective To describe the correlation between clinical and laboratory variables with histological biopsy-proven lupus nephritis. Methods An analytical cross-sectional study was conducted, between January, 2004 and December, 2012. Qualitative variables were described using absolute and relative frequencies, while quantitative variables were assessed by medians with interquartile range. The relationship with clinical findings was explored using chi-square maximum likelihood test, adjusted standardized residuals, hierarchical Kruskal–Wallis test, homogeneity of variance in data, post hoc Dunn's test, Spearman's correlation coefficient, and Mann–Whitney test. Results 132 patients were included. Proliferative lupus nephritis was the most frequent (74%). The most common clinical condition was nephritic syndrome (46%); proteinuria was observed in 80%. No relationship was found between clinical syndromes and histological types; only statistically significant differences were observed between proliferative and non-proliferative forms regarding hematuria (72.1 vs. 46.7%; p = 0.012), C3 hypocomplementemia (70.9 vs. 43.3%; p = 0.007), 24-h proteinuria (2560 vs 741 mg; p = 0.001), and serum creatinine (1 vs. 0.77 mg/dL; p = 0.006). We found positive correlations between activity index and serum creatinine values, 24-h proteinuria, C3 hypocomplementemia, along with positive anti-DNA antibodies. Conclusion There is a clinicopathological relationship within proliferative types and certain laboratory features (hematuria, elevated 24-h protein excretion, serum creatinine level, and C3 hypocomplementemia) in a mestizo population with lupus nephritis; nonetheless, no association was found with any other variables.