Characteristics of Diabetic Ketoacidosis in Older versus Younger Adults

Objective To describe how diabetic ketoacidosis in those aged 65 or over differs from that in younger adults. Design Retrospective chart review of all adult patients with a primary or secondary discharge diagnosis of diabetic ketoacidosis ( n = 338). Setting Three urban teaching hospitals in Milwaukee, WI from January 1, 1987 to May 31, 1990. Patients Two hundred twenty cases in 150 patients met our criteria for severity of illness to be included in the study. Twenty‐seven cases were in patients ≥ age 65; 193 cases were in patients < age 65. Results The older patients were less likely to have been using insulin before hospitalization (55.6% vs 80.2%, P = 0.004) and less likely to have had a prior episode of diabetic ketoacidosis (8.0% vs 51.4%, P = 0.001). The presenting laboratory data were not significantly different between older and younger subjects. There was a trend toward a higher mean insulin dosage to bring the patient's blood glucose to ≤300 mg/dL for those age 65 or older; 69.1 units vs 44.9 units ( P = 0.06). The time required to obtain a glucose <300 mg/dL was greater in older patients (10.5 vs 7.7 hours, P = 0.01). The average length of stay for those age 65 or older was 12.4 days vs 6.7 days ( P = 0.001). Thirdly, of those age 65 or older, 7% vs 29% of younger subjects had a blood glucose or Accucheck ≤ 49 mg/dL at some time during their hospital course. The hypoglycemic episodes were more likely to be asymptomatic in older patients ( P = 0.03). The mortality rate was 22% for those age 65 or older vs 2% for younger subjects ( P = 0.001). The mortality rate for those in age groups 60–69 years, 70–79 years, and ≥ 80 years was 8%, 27%, and 33%, respectively. In patients ≥ 65, mortality was confined to those with coexisting renal disease or infection. Conclusion Older patients with diabetic ketoacidosis are less likely to have been using insulin before hospitalization. They tend to receive more insulin therapy during their acute management, have a longer average length of hospital stay, and have a higher mortality rate.