Natural history and prognostic factors of diabetic nephropathy in type 2 diabetes

• Published in: QJM : An International Journal of Medicine 2002-06, Vol.95 (6), p.371-377
• Main Authors: Jude, E.B., Anderson, S.G., Cruickshank, J.K., Srivatsa, A., Tentolouris, N., Chandrasekaran, R., Gokal, R., Boulton, A.J.M.
• Format: Article
• Language: English
• Subjects: Aged; Associated diseases and complications; Biological and medical sciences; Cohort Studies; Diabetes Mellitus, Type 2 - complications; Diabetes Mellitus, Type 2 - mortality; Diabetes. Impaired glucose tolerance; Diabetic Nephropathies - complications; Diabetic Nephropathies - mortality; Endocrine pancreas. Apud cells (diseases); Endocrinopathies; Female; Humans; Male; Medical sciences; Middle Aged; Prognosis; Proportional Hazards Models; Proteinuria - etiology; Proteinuria - mortality; Retrospective Studies; Risk Factors; Survival Analysis
• ISSN: 1460-2725; 1460-2393; 1460-2393
• DOI: 10.1093/qjmed/95.6.371

Background: The causes and mechanisms of increased mortality of patients with diabetic nephropathy are unclear, and its natural history is poorly understood. Aim: To evaluate risk factors for mortality in type 2 diabetic patients with nephropathy. Design: Retrospective study of clinical and biochemical parameters in diabetic nephropathic patients and controls sampled from a secondary care register. Methods: We studied 170 type 2 diabetic patients (from 1987 to 1995) with nephropathy (proteinuria >0.5 g/24 h) and 170 non‐nephropathic patients. Follow‐up was until death or December 1997. Details of demographics, clinical and treatment history were obtained from medical records. Results: Mean follow‐up was 5.3 years. Of the patients with nephropathy at baseline, 63 (37%) died compared with 14 (8%) non‐nephropathic patients (χ2=53.8, p2 g/24 h, 9.9 (7.3–13.5) per 100 patient‐years. A 36% (5–78%) excess risk of mortality was observed for each log unit increase in proteinuria. Multivariate Cox regression analyses confirmed a five‐fold excess risk for all‐cause and cardiovascular mortality in patients with nephropathy compared with those without. This was independent of other risk factors including baseline age [5% (1–8%)/year], creatinine [2.5 (1.12–5.6)/10 μmol/l] and glycaemic control (HbA1c) [15% (1–31%) per 1% rise]. Conclusions: Proteinuria is a potentially preventable and reversible risk factor associated with high mortality in type 2 diabetic patients. Prevention of the development of overt nephropathy and improvement in diabetes control may reduce mortality in these patients.