Relationship of elevated urinary albumin excretion to components of the metabolic syndrome in non-insulin-dependent diabetes mellitus

Abstract

Microalbuminuria is associated with increased morbidity and early mortality in non-insulin-dependent diabetes mellitus (NIDDM), mostly due to cardiovascular disease. This association may be due to a higher prevalence of known cardiovascular risk factors in those with microalbuminuria. We examined the relationship of microalbuminuria to components of the metabolic syndrome in 98 NIDDM patients with elevated urinary albumin excretion rate (UAER) (>10.5 μg/min) (high UAER) and 102 normoalbuminuric NIDDM patients. Patients with high UAER were older than normoalbuminuric patients ( P<0.05), but they did not differ with respect to duration of diabetes, total cholesterol, body mass index (BMI) or the prevalence of smoking. A total of 58 (60%) patients with elevated UAER had two or more of hypertension, ischaemic heart disease (IHD), hypertriglyceridaemia and obesity compared with 41 (40%) in the normoalbuminuric group, ( P<0.05). Only nine (9.2%) high UAER patients had none of the above risk factors compared with 26 (25.5%) in the normoalbuminuric group ( P<0.01). The prevalence of hypertension (blood pressure (BP)>160/95) was significantly higher in high UAER patients; 61/98 (62%) versus 39/102 (38%) in normoalbuminuric group, ( P<0.05). Elevated UAER was also associated with a higher risk of macrovascular disease ( P<0.01). The high UAER group included 50 Caucasian, 30 Asian and 18 Afro-Caribbean. The three groups did not differ with respect to total cholesterol, glycosylated haemoglobin (HbA 1c) or prevalence of smoking. Asians had a lower BMI, a lower BP and a lower prevalence of peripheral vascular disease (PVD), but had a higher serum triglyceride ( P<0.01 for all) compared with Caucasian. Patients of Afro-Caribbean origin had a lower prevalence of IHD (0%) compared with both Asians (16%) and Caucasians (22%). Elevated UAER in NIDDM is closely associated with components of the metabolic syndrome and an increased risk of IHD and PVD. There are however, significant ethnic differences in this association.