A prospective study of uric acid by glucose tolerance status and survival: the Rancho Bernardo Study.

OBJECTIVES: Little is known about uric acid (UA) levels and mortality in the context of glycaemia. We examined whether serum UA levels predict all-cause and cardiovascular disease (CVD) mortality differentially in older adults by glucose tolerance status.

DESIGN AND METHODS: Between 1984 and 1987, 2342 community-dwelling men and women had an oral glucose tolerance test, UA measurement, and assessment of traditional CVD risk factors. We defined glucose tolerance status as normoglycaemia (NG), pre-diabetes (pre-DM), and type 2 diabetes mellitus (T2DM). Ninety per cent were followed for vital status up to 23 years. Death certificates were coded using the Ninth International Classification of Diseases.

RESULTS: Baseline age was 69.5 years; 44.4% were men. At baseline 939 had NG, 957 pre-DM, and 446 T2DM. The mean UA by glucose tolerance status was 327.1, 362.8, and 374.7 micromol L(-1). During follow-up, there were 1318 deaths 46.8% attributed to CVD. In Cox-regression analysis, each 119 micromol L(-1) (2 mg dL(-1)) increment in UA levels predicted an increased hazard ratio (HR) for all-cause deaths independent of age, smoking, body mass index, alcohol, physical activity, diuretic use and estimated glomerular filtration rate in all groups (NG: HR 1.25 95% CI 1.06-1.47, P =0.005; pre-DM: HR 1.20 95% CI 1.06-1.37, P = 0.04; T2DM: HR 1.20 95% CI 1.01-1.47, P = 0.04). After adjusting for CVD risk factors, the UA association with CVD mortality was significant only in the pre-DM and T2DM groups.

CONCLUSION: All-cause mortality was independently associated with UA in all groups, but UA predicted CVD mortality only in those with abnormal glucose tolerance.