Clinico-Pathological Correlation of Severe
Tubulointerstitial Fibrosis in Glomerular Diseases
Nuttasith Larpparisuth MD*,
Duangrat Tanratananon MD*, Bunyarit Cheunsuchon MD**,
Paisan Parichatikanon MD**, Somkiat Vasuvattakul MD*
Affiliation :
* Division of Nephrology, Department of Medicine, Faculty of Medicine Siriraj Hospital, Mahidol University, Bangkok, Thailand
** Department of Pathology, Faculty of Medicine Siriraj Hospital, Mahidol University, Bangkok, Thailand
Background : Renal histopathology is the best method available to assess chronicity of glomerular diseases. However, renal
biopsy is an invasive procedure and is available only in medical schools or tertiary-care hospitals in Thailand. Clinical
predictors that discriminate the chronicity index of renal pathology may be valuable for the best timing of biopsy. The
authors conducted this study to identify the clinical parameters of severe fibrosis in glomerular diseases.
Material and Method: The authors retrospective analyzed all consecutive patients with glomerular diseases who underwent
ultrasound-guided renal biopsy in Siriraj Hospital between 2008 and 2010. The patients were statified according to degree
of tubulointerstitial fibrosis (IF) into mild to moderate group (IF <50%) and severe group (IF ≥50%). Data of clinical and
radiological parameters which relate to severe fibrosis were obtained. Formula for prediction of advanced IF was also
developed by backward stepwise logistic regression analysis. The authors also validated the model by application to the
patients who underwent kidney biopsy in our center between 2011 and 2012.
Results : Of a total 682 patients, 169 patients (24.8%) were classified as a severe IF group. In the multivariate model, higher
serum creatinine, lower mean length of both kidneys and systolic blood pressure (SBP) of more than 140 mmHg were
significantly related to severe IF. All three factors were incorporated into a predictive model: ex/(1+ex) while x = 1.3+(0.6
x serum Cr in mg/dl)–(0.4 x mean length of both kidneys in cm)+(0.7 x 1 if SBP ≥140 mmHg or 0 if <140 mmHg). The
formula had AUROC of 0.82 and if calculated probability of fibrosis is higher than 0.37, it yields 90% specificity and 44%
sensitivity for the prediction of severe fibrosis. When applied to 523 patients who underwent renal biopsy in 2011 and 2012,
the sensitivity was 65.6% while specificity was 87.8%.
Conclusion : High serum creatinine, presence of HT and decreased mean length of both kidneys are important clinical
markers to predict renal fibrosis. The model constructed from these factors could be used in clinical practice for appropriate
decision making.
Keywords : Tubulointerstitial fibrosis, Chronicity index, Renal pathology, Renal ultrasonography, Glomerular diseases
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