The joint diabetic-renal clinic in clinical practice: 10 years of data from a District General Hospital

BACKGROUND

Diabetic nephropathy is the leading cause of end-stage renal failure. Untreated, it causes continuous decline in glomerular function, worsening hypertension and a marked increase in cardiovascular risk. Joint diabetic-renal clinics were established to address these factors and prepare patients for renal replacement therapy.

AIM

To determine whether our joint diabetic-renal clinic influenced progression of renal disease, and whether we were able to achieve targets from clinical trials and guidelines in routine practice.

DESIGN

Retrospective review.

METHODS

We collected data using clinical notes and electronic records for 130 patients attending the clinic over 10 years.

RESULTS

Our patients had 62% type 2 and 38% type 1 diabetes. Mean duration of diabetes was 24 years for type 1 and 11 years for type 2 diabetes. At referral, 56% had evidence of vascular disease and 45%, proliferative retinopathy. Baseline median creatinine was 124 micromol/l. Significant improvements were made in systolic BP, diastolic BP and cholesterol (p < 0.001), compared to measurements at presentation. We analysed progression of renal disease by linear regression on 45 patients who had follow-up data for 3 years. Rate of decline of GFR was significantly reduced from 1.09 ml/min/month in the first year to 0.39 ml/min/month in the third year, (p < 0.004).

DISCUSSION

Our findings suggest that the rate of deterioration of renal function can be reduced by aggressive management of risk factors. Joint diabetic-renal clinics appear to be useful in achieving targets in routine clinical practice.

Na/Li countertransport abnormalities in type 1 diabetes with and without nephropathy are familial

OBJECTIVE

To determine whether there is a familial abnormality in erythrocyte Na/Li countertransport (CT) kinetics in the approximate one-third of type 1 diabetic patients that succumb to a familial predisposition to nephropathy.

RESEARCH DESIGN AND METHODS

Erythrocyte Na/Li CT kinetics were measured in nondiabetic first-degree relatives of type 1 diabetic patients with nephropathy (DNrel) (n = 32) or without nephropathy (DCrel) (n = 22) and normal control subjects ( n = 25).

RESULTS

Increases in outside-site Na ion association rate constant and turnover rate of Na/Li countertransport (CT) in DNrels caused increases in Vmax/Km and Vmax, respectively. Thiol alkylation with N-ethy]maleimide (NEM) modifies these kinetic parameters abnormally in nephropathy. With Na ions at the outside site of the transporter, thiol alkylation causes a large decrease in Vmax; but in their absence, Vmax is decreased in normal control subjects, unchanged in DCrels, or increased in DNrels. The relationship between Vmax values after thiol alkylation with or without Na ions was different in DNrels (P < 0.001). Kinetic parameters with and without thiol alkylation identified 60% of DNrels and 20% of DCrels as abnormal. The single-flux rate assay of Na/Li CT did not give this discrimination, and its use may cause discrepancy between studies.

CONCLUSIONS

Clinically normal untreated DNrels have the same abnormality in Na/Li CT as the affected patients. DNrels had a metabolic syndrome with increased BMI and plasma triglycerides, but no elevation in blood pressure. Na/Li CT can detect those type 1 diabetic patients at risk of nephropathy who have a familial abnormality in a membrane thiol protein.