Lipoprotein(a) concentration in diabetes: relationship to proteinuria and diabetes control

Diabetic patients are at increased risk of cardiovascular disease, particularly when proteinuria is present. Lipoprotein(a)[Lp(a)] levels were assessed in 37 patients with insulin dependent (IDDM) and in 75 patients with non-insulin dependent (NIDDM) diabetes who showed varying degrees of proteinuria and glycaemic control. Median Lp(a) in 112 diabetic patients was significantly greater than in 116 healthy controls (113 vs 48 mg/L; p less than 0.01). 86 of the patients had first morning urine albumin concentration less than 30 mg/L (normoalbuminuria = NA), 16 patients 30-200 mg/L (microalbuminuria = MA) and ten patients greater than 200 mg/L (albuminuria = ALB). There was no significant difference in median Lp(a) concentration between the three groups (NA = 108, MA = 163, ALB = 98 mg/L; p greater than 0.5). No significant difference in median Lp(a) or NIDDM treated with oral agents and/or diet (120, 98, 115 mg/L respectively; p greater than 0.7). When the 86 NA patients were divided on the basis of median fructosamine concentration (357 mumol/L), no significant difference was found in median Lp(a) levels between those grouped below or above this median (98 mg/L vs 118 mg/L; p greater than 0.5). Across all diabetics studied there was no significant correlation present between Lp(a) and urinary protein or glycaemic control. These cross-sectional results suggest that median Lp(a) concentration is increased in both IDDM and NIDDM patients, but this increase is not related to the degree of proteinuria or short-term glycaemic control.