Abdulla Watad1,2,3, Nicola Luigi Bragazzi4, Kassem Sharif1,3, Ora Shovman1,3, Boris Gilburd2, Howard Amital1,2,3, Yehuda Shoenfeld2,3. 1. Department of Medicine 'B', Sheba Medical Center, Tel Hashomer, Israel. 2. Zabludowicz Center for Autoimmune Diseases, Sheba Medical Center, Tel Hashomer, Israel. 3. Sackler Faculty of Medicine, Tel Aviv University, Tel Aviv, Israel. 4. School of Public Health, Department of Health Sciences (DISSAL), University of Genoa, Genoa, Italy.
Abstract
BACKGROUND: Anti-glomerular basement membrane (GBM) antibody disease, or Goodpasture's disease, is the clinical manifestation of the production of anti-GBM antibodies, which causes rapidly progressive glomerulonephritis with or without pulmonary hemorrhage. Anti-GBM antibody detection is mandatory for the diagnosis of Goodpasture's disease either from the serum or kidney biopsy. Renal biopsy is necessary for disease confirmation; however, in cases in which renal biopsy is not possible or is delayed, serum detection of anti-GBM antibody is the only way for diagnosis. OBJECTIVES: To assess the predictive value of positive anti-GBM antibodies in a clinical setting. METHODS: Data from anti-GBM antibody tests performed at one medical center between 2006 and 2016 were systematically and retrospectively retrieved. We recruited 1914 patients for the study. Continuous variables were computed as mean ± standard deviation, while categorical variables were recorded as percentages where appropriate. Sensitivity and specificity of anti-GBM titers were calculated. Kaplan-Meyer analysis was performed, stratifying survival according to the anti-GBM antibody titers. RESULTS: Of the 1914 anti-GBM test results detected, 42 were positive, 23 were borderline, 142 were excluded, and 1707 results were negative. Male-to-female ratio was 1:1.2. Sensitivity of anti-GBM test was 41.2% while specificity was 85.4%. Concerning the Kaplan-Meyer analysis, overall survival was 1163.36 ± 180.32 days (median 1058 days). CONCLUSIONS: Our study highlights the lack of sensitivity of serological testing of anti-GBM titers. Comparing survival curves, the survival correlated with anti-GBM titer only in a borderline way. Because highly sensitive bioassays are not routinely used in clinics, renal biopsy is still pivotal for Goodpasture's disease diagnosis.
BACKGROUND: Anti-glomerular basement membrane (GBM) antibody disease, or Goodpasture's disease, is the clinical manifestation of the production of anti-GBM antibodies, which causes rapidly progressive glomerulonephritis with or without pulmonary hemorrhage. Anti-GBM antibody detection is mandatory for the diagnosis of Goodpasture's disease either from the serum or kidney biopsy. Renal biopsy is necessary for disease confirmation; however, in cases in which renal biopsy is not possible or is delayed, serum detection of anti-GBM antibody is the only way for diagnosis. OBJECTIVES: To assess the predictive value of positive anti-GBM antibodies in a clinical setting. METHODS: Data from anti-GBM antibody tests performed at one medical center between 2006 and 2016 were systematically and retrospectively retrieved. We recruited 1914 patients for the study. Continuous variables were computed as mean ± standard deviation, while categorical variables were recorded as percentages where appropriate. Sensitivity and specificity of anti-GBM titers were calculated. Kaplan-Meyer analysis was performed, stratifying survival according to the anti-GBM antibody titers. RESULTS: Of the 1914 anti-GBM test results detected, 42 were positive, 23 were borderline, 142 were excluded, and 1707 results were negative. Male-to-female ratio was 1:1.2. Sensitivity of anti-GBM test was 41.2% while specificity was 85.4%. Concerning the Kaplan-Meyer analysis, overall survival was 1163.36 ± 180.32 days (median 1058 days). CONCLUSIONS: Our study highlights the lack of sensitivity of serological testing of anti-GBM titers. Comparing survival curves, the survival correlated with anti-GBM titer only in a borderline way. Because highly sensitive bioassays are not routinely used in clinics, renal biopsy is still pivotal for Goodpasture's disease diagnosis.