Characteristics of diabetic ketoacidosis in older versus younger adults

Abstract

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 > or = 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 < or = 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 < or = 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 > or = 80 years was 8%, 27%, and 33%, respectively. In patients > or = 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.