LONG-TERM INSTABILITY OF FASTING PLASMA-GLUCOSE PREDICTS MORTALITY INELDERLY NIDDM PATIENTS - THE VERONA DIABETES STUDY

The aim of this study was to evaluate whether long-term glucose contro l, as assessed by fasting plasma glucose determinations during 3 years , is a predictor of all-cause mortality in elderly NIDDM patients. Fiv e hundred and sixty-six NIDDM patients attending the Verona Diabetes C linic, aged 75 years and over, were followed-up from 1 January 1987 to 31 December 1991 to assess all-cause mortality. From their clinical r ecords all fasting plasma glucose determinations available for the yea rs 1984 to 1986 were collected and analysed. Patients were grouped in tertiles according to mean (M-FPG), coefficient of variation (CV-FPG) and trend over time (slope, S-FPG) of fasting plasma glucose during th e period of retrospective evaluation, Mortality was assessed by observ ed/expected ratios, univariate Kaplan-Meier survival analysis and mult ivariate Poisson regression model. By 31 December 1991, 61 men and 127 women had died. Increased observed/expected ratios were found in wome n from the top M-FPG tertile, in patients (men and women) from the top CV-FPG tertile and in patients with a S-FPG less than -0.30 mmol/l pe r year (lowest tertile). Patients in the lowest tertile of CV-FPG and in the middle tertile of S-FPG had a reduced mortality risk. Kaplan-Me ier survival analysis indicated that patients with high CV-FPG as well as those in tertiles I and III of S-FPG (i.e., those with a definitel y negative or definitely positive slope) had an increased probability of dying, without any significant differences between the three tertil es of M-FPG. Poisson regression model showed that CV-FPG, but not M-FP G or S-FPG, was an independent significant predictor of mortality, The se results suggest that glucose stability needs to be considered along with the absolute level of metabolic control when treating elderly NI DDM patients.