Abstract: | Background:Emerging data highlight the interactions of preadmission glycemia, reflected by admission HbA1c levels, glycemic control during critical illness, and mortality. The association of preadmission insulin treatment with outcomes is unknown.Methods:This observational cohort study includes 5245 patients admitted to the medical-surgical intensive care unit of a university-affiliated teaching hospital. Three groups were analyzed: patients with diabetes with prior insulin treatment (DM-INS, n = 538); patients with diabetes with no prior insulin treatment (DM-No-INS, n = 986); no history of diabetes (NO-DM, n = 3721). Groups were stratified by HbA1c level: <6.5%; 6.5%-7.9% and >8.0%.Results:Among the three strata of HbA1c, mean blood glucose (BG), coefficient of variation (CV), and hypoglycemia increased with increasing HbA1c, and were higher for DM-INS than for DM-No-INS. Among patients with HbA1c < 6.5%, mean BG ≥ 180 mg/dL and CV > 30% were associated with lower severity-adjusted mortality in DM-INS compared to patients with mean BG 80-140 mg/dL and CV < 15%, (P = .0058 and < .0001, respectively), but higher severity-adjusted mortality among DM-No-INS (P = .0001 and < .0001, respectively) and NON-DM (P < .0001 and < .0001, respectively). Among patients with HbA1c ≥ 8.0%, mean BG ≥ 180 mg/dL was associated with lower severity-adjusted mortality for both DM-INS and DM-No-INS than was mean BG 80-140 mg/dL (p < 0.0001 for both comparisons).Conclusions:Significant differences in mortality were found among patients with diabetes based on insulin treatment and HbA1c at home and post-admission glycemic control. Prospective studies need to confirm an individualized approach to glycemic control in the critically ill. |