เปรียบเทียบการประเมินพังผืดในเนื้อเยื่อไตระหว่างวิธีการประเมิน ด้วยสายตาและประเมินโดยใช้การวิเคราะห์ภาพดิจิตอลในผู้ป่วยไต อักเสบจากโรคลูปัส

Abstract

Background: Prediction of the renal outcomes is crucial for patients with lupus nephritis due to high morbidity and mortality. Renal interstitial fibrosis is correlated with progression to renal failure. However evaluation of interstitial fibrosis by subjective visual assessment comparing with digital image analysis has not been well studied. Method: Seventy-five kidney core biopsies diagnosed with lupus nephritis at Chiang Mai University hospital during July 1st, 2011 to December 31th, 2012 were retrieved from database. Interstitial fibrosis in percentage was assessed on scanned PicroSirius red stained histological images (Aperio) using software analysis. Visual assessment was performed under a light microscope by two pathologists (SS, SL). Clinical, laboratory data and renal outcomes (end-stage renal disease (ESRD), doubling serum creatinine (DSC), dialysis and complete remission (CR)) were collected retrospectively from the time of biopsy to the last follow-up. Result: Interstitial fibrosis evaluated by image analysis (IF-IA) showed better intraobserver (Pearson correlation coefficient: r=0.98, p<0.001 VS r=0.85, p<0.001) and interobserver reliability (r=0.79, p<0.001 VS r=0.61, p=0.001) compared with interstitial fibrosis evaluated by visual assessment (IF-VA) While IF-VA showed a greater negative correlation with baseline estimated glomerular filtration rate (eGFR) (r= -0.458, p<0.001) compared with IF-IA (r= -0.246, p=0.033). A significantly greater degree of IF-VA was observed in patients with subsequent ESRD, DSC and dialysis; and a significantly lesser degree of IF-VA was observed in patients with CR compared with patients without these outcomes. Whilst there is no difference in IF-IA between patients with and without such renal outcomes. Univariate survival analysis (log-rank test) showed IF-VA, IF-IA, serum creatinine, hematocrit, serum C3 protein and eGFR were predictive of all adverse renal outcomes. However multivariate Cox-hazard analysis demonstrated that only IF-VA was an independent predictor for ESRD (Hazard ratio: 1.062, 95% confidence interval: 1.034-1.092, p<0.001). Using Kaplan-Meier curves and log-rank test, IF-VA but not IF-IA, is inversely associated with renal survival from ESRD, DSC and dialysis (P<0.001). The median renal survival of ESRD in patient with IF-VA >50% was 2.1 months compared with 27.16 months in those with IF-VA 25-50%.

Conclusion: Renal interstitial fibrosis evaluated by digital image analysis is more reliable and precise, however assessing by visual assessment is more predictive of renal outcomes in lupus nephritis patients.