To identify characteristics of adult patients at baseline associated with duration of subsequent, continuous, subcutaneous infusion of insulin treatment (pump therapy) of type I diabetes.
For 6 wk, patients followed a standardized conventional therapy and kept a record of insulin dosages, capillary blood glucose concentrations, and symptomatic hypoglycemia. They were then hospitalized. Additional baseline data were obtained and pump therapy was started. Survival analysis was used to determine the relationship between baseline independent variables or risk factors and duration of pump therapy, which is the dependent variable.
Of the 68 participants, 33 (49%) terminated pump therapy after an average of 9.9 mo of treatment. Two models (each P < 0.00005) were developed that exhibited a high degree of consistency. Of the 6 variables, 5 were common to both models (HbA1 autonomic neuropathy, mean amplitude of glycemic excursions, frequency of symptoms of hypoglycemia when blood glucose was < 70 mg/dl, and erythema at injection sites). The sixth variable in model 1 (insulin dosage) was replaced in model 2 by a variable, Adult Self-Efficacy for Diabetes, which was obtained on the 33 more recently enrolled patients; this variable related to patient perceptions of self-care behaviors.
We found that, at baseline, the presence of a high concentration of HbAx and a low estimation by the patient of their ability to treat the disease portend failure of insulin pump therapy as evidenced by its discontinuation. This effect is accentuated when clinical evidence of autonomic neuropathy is observed. These findings offer guidance in selecting patients with type I diabetes for insulin pump therapy.