Very low incidence of end stage renal disease (ESRD) was found in patients with childhood-onset type 1 diabetes in Norway.
Many patients with both type 1 and type 2 diabetes develop complications of the disease. Diabetic nephropathy is one of those very severe complications of type 1 diabetes. This type of complication has high rates of mortality. Geographical variations have been found in the incidence of end stage renal disease (ESRD) among children with type 1 diabetes. ESRD is defined as when there is a need to start dialysis or transplantation due to renal failure. The goal of this study was to evaluate incidence of ESRD by sex, age at diagnosis and the year of diagnosis of diabetes in individuals with up to 42 years of follow-up.
This study obtained data from the Norwegian Childhood Diabetes Registry that included cases of childhood onset diabetes in Norway. Individuals with genetically verified monogenic diabetes, diabetes diagnoses before 6 months of age and those with type 2 diabetes were excluded from this study. Study population included individuals that were diagnosed with type 1 diabetes from January 1, 1973 to December 31, 1982 and from January 1, 1989 to December 31, 2012. Individuals were followed up from diagnosis of type 1 diabetes to the diagnosis of ESRD, death, emigration or to the date November 30, 2015 (whichever occurred first).
According to the results, it was found that 285 individuals died and 103 individuals developed ESRD due to diabetic nephropathy from a total of 7,871 individuals with type 1 diabetes during a mean follow-up period of 18.8 years. 18 of the 103 patients (17.5%) had transplantation performed. There was a total of seven patients found with ESRD due to primary glomerulonephritis (n=4), interstitial nephropathies (n=2) or multisystem disease (n=1). However, these seven cases were not included in the analysis of the results. The average duration from diagnosis of type 1 diabetes to the development of ESRD was about 25.9 years. Both men and women were found to have similar mean age at the development of ESRD (about 35.9 years). It was found that ESRD only developed in three cases before 15 years after the diagnosis of diabetes. However, the incidence of ESRD substantially increased between 15 and 25 years after diagnosis of diabetes. Furthermore, results found that the probability of developing ESRD was 39% lower in women than in men and 29% higher in individuals in whom diabetes was diagnosed after age 10.
Overall, this study showed that the cumulative incidence of ESRD in Norway was very low: 0.7% at 20 years, 2.9% at 30 years and 5.3% at 40 years after the diagnosis of type 1 diabetes. The cumulative incidence of ESRD in individuals with type 1 diabetes was estimated to be 9-11% at 25 years in the U.S and 7.8% at 30 years in Finland after diagnosis of diabetes. In general, the incidence of ESRD is lower in Western European countries compared with the U.S. These results are influenced by many factors. One of them being that intensified insulin treatment was used at an early point in Norway to achieve near-normoglycemia. The effect of normoglycemia on diabetic nephropathy was shown in the Oslo Study in 1986 and these results led to the use of more aggressive treatment to achieve near-normoglycemia at an early point in Norway. Also, there was the use of ACE inhibitors in normotensive patients with type 1 diabetes with microalbuminuria. Authors also believe that the low risk of ESRD may be related to the Norwegian health care system where equal healthcare is provided to all patients without extra cost. The risk of development of ESRD was higher in men compared to women in those who were diagnosed at a young age. This sex difference could be due to modifiable risk factors such as blood pressure control, lifestyle, renal physiology, and maybe because women may use the healthcare more frequently and be more compliant with the suggested treatment than men. After 35 years of the diagnosis of diabetes, the cumulative mortality was 9.1%.
Furthermore, it was observed that there was a 39% lower risk of developing ESRD if diabetes was diagnosed before 10 years of age compared to 10-14 years. These findings might be due to both psychological and endocrine factors that are crucial during pubertal period. Chronic complications can develop due to hormonal changes and poor glycemic control. In conclusion, this study reported that the risk of development of ESRD in Norway with childhood onset type 1 diabetes was lower than reported in other countries. Also, the diagnosis of diabetes before pubertal age has lower risk in development of ESRD.
- The development of ESRD in individuals with type 1 diabetes was lower in Norway than in other countries.
- There was a lower risk of development of ESRD in individuals who have been diagnosed with type 1 diabetes before pubertal age.
- The probability of developing ESRD was much lower in women than in men.
Gagnum V, Saeed M, Stene L, et al. Low Incidence of End-Stage Renal Disease in Childhood-Onset Type 1 Diabetes Followed for Up to 42 years. Diabetes Care. 2018; 41:420-25.
Vidhi Patel, Pharm. D. Candidate 2018, LECOM School of Pharmacy