ARTICLE Risk of renal disease in patients with both type 1 diabetes and coeliac disease Kaziwe Mollazadegan & Michael Fored & Sigrid Lundberg & Johnny Ludvigsson & Anders Ekbom & Scott M. Montgomery & Jonas F. Ludvigsson Received: 15 January 2014 /Accepted: 7 March 2014 # Springer-Verlag Berlin Heidelberg 2014 Abstract Aims/hypothesis Our aim was to study the risk of renal disease in patients with type 1 diabetes (T1D) and coexisting coeliac disease (CD). Methods Individuals with T1D were defined as having a diagnosis of diabetes recorded at ≤30 years of age in the Swedish Patient Register between 1964 and 2009. Individuals with CD were identified through biopsy reports with villous atrophy (Marsh stage 3) from 28 pathology departments in Sweden between 1969 and 2008. We identified 954 patients with both T1D and CD. For each patient with T1D + CD, we selected five age- and sex-matched reference individuals with T1D only (n =4,579). Cox regression was used to estimate the following risks: (1) chronic renal disease and (2) end-stage renal disease in patients with CD + T1D compared with T1D patients only. Results Forty-one (4.3%) patients with CD + T1D and 143 (3.1%) patients with T1D only developed chronic renal dis- ease. This corresponded to an HR of 1.43 for chronic renal disease (95% CI 0.94, 2.17) in patients with CD + T1D compared with T1D only. In addition, for end-stage renal disease there was a positive (albeit statistically non- significant) HR of 2.54 (95% CI 0.45, 14.2). For chronic renal disease, the excess risk was more pronounced after >10 years of CD (HR 2.03, 95% CI 1.08, 3.79). Risk estimates were similar when we restricted our cohort to the following T1D patients: (1) those who had an inpatient diagnosis of T1D; (2) those who had never received oral glucose-lowering medica- tion; and (3) those who had not received their first diabetes diagnosis during pregnancy. Conclusions/interpretation Overall this study found no ex- cess risk of chronic renal disease in patients with T1D and CD. However, in a subanalysis we noted a positive association between longstanding CD and chronic renal disease in T1D. Keywords Coeliac disease . Cohort studies . Renal disease . Type 1 diabetes Abbreviations CD Coeliac disease ESRD End-stage renal disease GFD Gluten-free diet T1D Type 1 diabetes VA Villous atrophy Electronic supplementary material The online version of this article (doi:10.1007/s00125-014-3223-y) contains peer-reviewed but unedited supplementary material, which is available to authorised users. K. Mollazadegan (*) : M. Fored : A. Ekbom : S. M. Montgomery : J. F. Ludvigsson Clinical Epidemiology Unit, Department of Medicine, Karolinska Institutet, 171 77 Stockholm, Sweden e-mail: kaziwe.mollazadegan@live.se K. Mollazadegan St Erik Eye Hospital, Department of Clinical Neuroscience, Karolinska Institutet, Stockholm, Sweden S. Lundberg Department of Medicine, Karolinska Institutet, Stockholm, Sweden J. Ludvigsson Div. of Pediatrics, Linköping University, and University Hospital, Östergötland County Council, Linköping, Sweden S. M. Montgomery Clinical Epidemiology and Biostatistics, Örebro University Hospital and Örebro University, Örebro, Sweden S. M. Montgomery Department of Epidemiology and Public Health, University College London, London, UK J. F. Ludvigsson Department of Pediatrics, Örebro University Hospital, Örebro, Sweden Diabetologia DOI 10.1007/s00125-014-3223-y