Added value of soluble tumor necrosis factor-α receptor 1 as a biomarker of ESRD risk in patients with type 1 diabetes

Carol Forsblom, John Moran, Valma Harjutsalo, Tony Loughman, Johan Wadén, Nina Tolonen, Lena Thorn, Markku Saraheimo, Daniel Gordin, Per Henrik Groop, Merlin C. Thomas, on behalf of the FinnDiane Study Group

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Abstract

OBJECTIVE: Recent studies have suggested that circulating levels of the tumor necrosis factor-α receptor 1 (sTNFαR1) may be a useful predictor for the risk of end-stage renal disease (ESRD) in patients with diabetes. However, its potential utility as a biomarker has not been formally quantified. RESEARCH DESIGN AND METHODS: Circulating levels of sTNFαR 1 were assessed in 429 patients with type 1 diabetes and overt nephropathy from the Finnish Diabetic Nephropathy (FinnDiane) cohort study. Predictors of incident ESRD over a median of 9.4 years of follow-up were determined by Cox regression and Fine-Gray competing risk analyses. The added value of sTNFαR1 was estimated via time-dependent receiver operating characteristic curves, net reclassification index (NRI), and integrated discrimination improvement (IDI) for survival data. RESULTS: A total of 130 individuals developed ESRD (28%; ESRD incidence rate of 3.4% per year). In cause-specific modeling, after adjusting for baseline renal status, predictors of increased incidence of ESRD in patients with overt nephropathy were an elevated HbA1c, shorter duration of diabetes, and circulating levels of sTNFαR1. Notably, sTNFαR1 outperformed estimated glomerular filtration rate in terms of R2. Circulating levels of the sTNFαR1 also remained associated with ESRD after adjusting for the competing risk of death. A prediction model including sTNFαR1 (as a 20.5 fractional polynomial) was superior to a model without it, as demonstrated by better global fit, an increment of R2, the C index, and area under the curve. Estimates of IDI and NRI(>0) were 0.22 (95% CI 0.16-0.28; P < 0.0001) and 0.98 (0.78-1.23; P < 0.0001), respectively. The median increment in the risk score after including sTNFαR1 in the prediction model was 0.18 (0.12-0.30; P < 0.0001). CONCLUSIONS: Circulating levels of sTNFαR 1 are independently associated with the cumulative incidence of ESRD. This association is both significant and biologically plausible and appears to provide added value as a biomarker, based on the absolute values of NRI and IDI.

Original languageEnglish
Pages (from-to)2334-2342
Number of pages9
JournalDiabetes Care
Volume37
Issue number8
DOIs
Publication statusPublished - 1 Jan 2014
Externally publishedYes

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