SWIDINEP a Swiss Diabetic Nephropathy Cohort
SWIDINEP a Swiss Diabetic Nephropathy Cohort
With our SWIDINEP cohort, we propose to explore the relationship between vascular risk
 markers and renal function decline in CKD stage 1-5. In order to realize these goals, we
 intend to recruit 200 patients within a 7y recruitment period (2014-2021). Recruitment is
 done in the nephrology and diabetes ambulatory clinics in the CHUV at Lausanne. Each eligible
 patient is identified and whether he/she can be proposed the study is discussed with the
 physician in charge of the patient. Once the patient is informed and has signed the consent
 form, he/she is examined in the Service of Nephrology at baseline, 2y and 5y.
Serum, plasma, and fresh urine samples as well as whole blood (buffy coat for DNA extraction
 and genotyping) are stored at -80°C in a local biobank according to the latest guidelines of
 the Académie Suisse des Sciences Médicales (ASSM).

 The vascular phenotype includes:

 -  24h ABPM with the examination of diurnal variations of blood pressure, pulse pressure
 and heart rate. Central pulse pressure is also calculated based on the pulse wave
 analysis providing information on stroke volume, central BP, aortic stiffness and
 arterial wave reflection. It increases with age and could expose glomerular capillaries
 to damage. It has been independently related to proteinuria.

 -  Arterial stiffness is assessed non-invasively with the commercially available Sphygmocor
 system (Version 8.0, At Cor Medical, Sydney, Australia) using applanation tonometry to
 measure carotid-femoral pulse wave velocity (PWV) and carotid and radial augmentation
 indexes. Pulse wave velocity is a strong surrogate for carotid-femoral arterial
 stiffness. Generally around 3-4m/s in the young population it increases with age. A high
 PWV brings to a greater transmission of pulsating pressure to the renal microcirculation
 and is associated with accelerated eGFR decline. Recently, a study has described its
 independent relationship with cardio-vascular mortality in CKD stage 2-4. Patients with
 a PWV at least at 10m/s had a HR for mortality of 5. Carotid and radial augmentation
 indexes measure the difference between the second and first systolic peak of the aortic
 wave and is expressed as a percentage of pulse pressure. They increase with age and have
 been correlated with eGFR and albuminuria.

 -  Carotid ultrasound is performed to assess carotid intima-media thickness. Carotid-intima
 media thickness is a direct measurement of atherosclerosis and can help stratify
 patients at CV risk. It has been associated with eGFR decline.

 -  Participants undergo a renal ultrasound including renal resistance index measurements as
 marker of intrarenal vascular disease according to a pre-specified protocol used
 previously in other local cohorts by the same experienced operator (PD Dr Menno Pruijm).
 The assessment of the intrarenal vessels is made by duplex Doppler sonography on 3
 segmental arteries (superior, middle, and inferior) in each kidney. The values are then
 averaged to obtain the mean value for each participant. Renal resistive index (RRI) is
 calculated as [(peak-systolic velocity - end-diastolic velocity)/peak-systolic
 velocity]. The Service of nephrology has performed an important study providing
 reference values in a population with normal renal ultrasounds. Renal resistive index
 has been associated with eGFR decline. Besides, all participants are screened for
 underlying renal artery stenosis based on well established intrarenal Doppler criteria.
 The presence of other renal structural abnormalities (renal cysts, tumors,
 calcifications and/or hydronephrosis) is also assessed. Finally, the bladder area is
 systematically visualized, as well as the prostatic gland in men.

 -  Subjects undergo ocular examination, including best-corrected visual acuity (BCVA), slit
 lamp biomicroscopic exam, measurement of intraocular pressure with a non-contact
 tonometer and fundus examination. Choroidal thickness is measured by the EDI-OCT
 technique. The subfoveal choroidal thickness is measured at macular fovea from the outer
 portion of the hyperreflective line corresponding to the RPE to the hyporeflective line
 or margin corresponding to the sclerochoroidal interface. Central macular retinal
 thickness is determined automatically in all eyes. There are emerging data regarding the
 relationship of choroidal circulation and various systemic and ocular diseases. The
 choroid is highly vascularized tissue that supplies blood to the outer retina, including
 the retinal pigment epithelium (RPE) cells and photoreceptors, especially in the foveal
 region where there is no retinal vasculature. The choroid plays a crucial part in the
 physiopathology of many retinal diseases. Details of the choroidal circulation remained
 largely unknown due to poor resolution and reproducibility of previous choroidal imaging
 techniques. Imaging of the choroid was dramatically improved with the development of
 spectral domain optical coherence tomography and was further augmented with the advent
 of enhanced depth imaging. The relation between renal dysfunction and impaired ocular
 microcirculation remains unclear, especially in early-stage diabetes. It's been reported
 that the blood flow in the retinal arterioles is decreased in patients with type 2
 diabetes with chronic kidney disease. Though, data on the relationship between choroidal
 thickness and diabetic nephropathy are sparse. As far as we are aware today, there is
 only one study that evaluated choroidal thickness alterations in diabetic nephropathy
 patients with early or no diabetic retinopathy. More precisely the subfoveal, temporal
 and nasal choroidal thickness was noted to be thinner in patients with diabetic
 nephropathy patients compared with non- diabetic nephropathy patients and normal
 subjects.

 Quality of life questionnaires: A number of studies have shown that as kidney function
 decreases, disease burden increases, with lower health-related quality of life (HRQoL) for
 patients with late stages of chronic kidney disease. However, few studies have looked into
 HRQoL and its determinants in the specific population of diabetic patients with kidney
 disease. Assessing HRQoL and its determinants is important in chronic care as studies have
 shown that patients with higher HRQoL function better within the healthcare system and
 perform more health-promoting activities. HRQoL is assessed at baseline in patients enrolled
 in the cohort. The impact of baseline HRQoL on renal function decline will be analysed.
Inclusion Criteria:

 -  Type 2 diabetes

 -  eGFR <60ml/min or albumine/creatinine ratio >3mg/mmol

 -  Can understand french and has signed the consent form.

 Exclusion Criteria:

 -  Age < 18y

 -  Another cause of nephropathy (excluding hypertensive nephropathy, obese related
 nephropathy)