Dietary risk factors for incidence or progression of chronic kidney disease in individuals with type 2 diabetes in the European Union

BACKGROUND: Although the prevalence of chronic kidney disease (CKD) is ∼ 30% in the group of people with diabetes, data on interventions in the very early stage of the disease are still missing. Furthermore, the effects of modifiable lifestyle factors such as nutrition on incidence and progression of CKD in patients with diabetes in Europe remain elusive. METHODS: We analyzed whether diet quality and adherence to dietary guidelines using the modified Alternate Healthy Eating Index (mAHEI) score was associated with CKD incidence or progression after 5.5 years in 3088 European participants of the ONgoing Telmisartan Alone and in combination with Ramipril Global Endpoint Trial (ONTARGET) with type 2 diabetes and baseline normo- or micro-albuminuria. Death was considered as a competing risk in the multinomial logit regression models, which were adjusted for age, gender, duration of diabetes, ONTARGET randomization, baseline albuminuria and glomerular filtration rate (GFR). We also estimated the potential impact on population health of improvement in diet quality. RESULTS: At study end, 450 (14.6%) participants had died and 926 (30%) had experienced the renal endpoint of incidence or progression of CKD, of which 422 (13.7%) participants had progressed to micro- or macro-albuminuria, 596 (19.3%) had a GFR-decline of >5% per year and 18 (0.6%) had developed end-stage renal disease. Participants in the healthiest tertile of the mAHEI score had a decreased risk of incidence or progression of CKD (odds ratio 0.8, 95% confidence interval 0.68-0.94) and death (0.65, 0.52-0.81) compared with participants in the least healthy tertile. If individuals with a suboptimal dietary quality (e.g. mAHEI < 28) were able to improve their diet to an mAHEI of 28, 3.2% of CKD incidence or progression and 10.0% of deaths might be avoided in 5.5 years. CONCLUSIONS: If the association between diet and these endpoints is causal, then optimizing diet quality in individuals with diabetes who have no CKD or very early CKD would have substantial population benefits in terms of prevention of CKD incidence or progression and mortality in this high-risk population.