Evaluation of urinary L-FABP as an early marker for diabetic nephropathy in type 2 diabetic patients

Background: Albuminuria is the standard biomarker for the diagnosis of diabetic nephropathy (DN). However, some patients with persistent microalbuminuria still progress to chronic kidney disease, raising the question of finding a better biomarker. This study aimed to evaluate the correlation of urinary liver-type fatty acid-binding protein (L-FABP) levels with renal function and to compare the role of urinary albumin-to-creatinine ratio (ACR) with urinary L-FABP in early detection of DN in type 2 diabetic patients.

Methods: The cross-sectional study was done on 106 type 2 diabetic patients and 30 non-diabetic people. L-FABP was measured with the Latex enhanced immunoturbidimetric technique.

Results: There was a strong and negative correlation between the urine L-FABP levels and eGFR (r = -0.606, p<0.001). The urinary L-FABP levels were significantly higher (p<0.001) in the normoalbuminuria diabetic group than the non-diabetic control group. The ROC-curve analyses in the diabetic patients and the normoalbuminuria diabetic patients showed that the AUCL-FABP was remarkably higher (p<0.001) than the AUCACR. An optimal cutoff value of 5 mg L-FABP/g Cr (with the sensitivity of 98.1% and specificity of 90%) and of 4.3 mg L-FABP/g Cr (with the sensitivity of 100% and specificity of 86.67%) was set to detect DN in the diabetic patients and the normoalbuminuria diabetic patients, respectively.

Conclusions: The change in urinary L-FABP levels happened earlier than in urinary albumin during renal function impairment. Urinary L-FABP can be used as a better indicator than ACR for early detection of DN in type 2 diabetes.

Uvod: Albuminurija je standardni biomarker za dijagnozu dijabetičke nefropatije (DN). Međutim, kod nekih pacijenata sa perzistentnom mikroalbuminurijom dolazi do hronične bolesti bubrega, pa se postavlja pitanje pronalaženja boljeg biomarkera. Ova studija je imala za cilj da proceni korelaciju nivoa jetrenog tipa vezujućeg proteina za masne kiseline (L-FABP) sa funkcijom bubrega i da uporedi ulogu urinarnog odnosa albumin-kreatinin (ACR) sa urinarnim LFABP u ranom otkrivanju DN kod pacijenata sa dijabetesom tipa 2.

Metode: Sprovedena je studija preseka na 106 bolesnika sa dijabetesom tipa 2 i 30 osoba koje nisu dijabetičari. L-FABP je meren Lateks pojačanom imunoturbidimetrijskom tehnikom.

Rezultati: Postoji jaka i negativna korelacija između nivoa L-FABP urina i eGFR (r = -0,606, p < 0,001). Nivoi LFABP u urinu su bili značajno viši (p < 0,001) u grupi dijabetičara normoalbuminurije nego u kontrolnoj grupi bez dijabetesa. Analiza ROC krive kod dijabetičara i kod pacijenata sa dijabetesom normoalbuminurije pokazala je da je AUCL-FABP značajno veći (p < 0,001) od AUCACR. Postavljena je optimalna granična vrednost od 5 mg L-FABP/g Cr (sa osetljivošću 98,1% i specifičnosti 90%) i 4,3 mg LFABP/g Cr (sa osetljivošću od 100% i specifičnosti od 86,67%) da bi se detektovala DN kod dijabetičara i normalno albuminurijskih dijabetičara, posebno.

Zaključak: Promena nivoa L-FABP u urinu se desila ranije nego u urinarnom albuminu tokom oštećenja bubrežne funkcije. Urinarni L-FABP se može koristiti kao bolji indikator od ACR-a za rano otkrivanje DN kod dijabetesa tipa 2.

Keywords: albuminuria; diabetic nephropathy; type 2 diabetes; urinary L-FABP.