Effect of continuous glucose therapy begun in infancy on the long-term clinical course of patients with type I glycogen storage disease.

BACKGROUND

To evaluate the effects of continuous glucose therapy on metabolic control, occurrence of severe hypoglycemia, physical growth and development, and complications of glycogen storage disease type I (GSD-I).

METHODS

Seventeen patients (11 males) with GSD-I were studied, mean age 14.6+/-5.0 (SD) years, in whom continuous glucose therapy was begun at 0.8+/-0.4 years. At the time of this study, subjects had received continuous glucose therapy for a total duration of 13.9+/-5.0 years. Uncooked cornstarch was used as the method of providing glucose continuously for 10.2+/-3.2 years. Subjects were admitted to the Clinical Research Center and followed their usual home dietary regimens, which included cornstarch supplements at 2- to 4-hour intervals during the day and at 4- to 8-hour intervals during the night. Plasma glucose, blood lactate, and glucoregulatory hormones were measured hourly for 24 hours.

RESULTS

During a 24-hour period of biochemical monitoring, mean hourly plasma glucose concentrations for the group of 17 subjects ranged from 76+/-17 (SD) mg/dl (4.2+/-0.9 mmol/l) to 108+/-16 mg/dl (6.0+/-0.9 mmol/l), and blood lactate concentrations ranged from 2.1+/-1.2 mmol/l to 3.8+/-2.8 mmol/l. Four subjects had transient plasma glucose levels of 50 mg/dl (2.8 mmol/l) or less in the interval between midnight and 8:00 AM. Mean blood lactate levels were highest (> or =3 mmol/l) between 2:00 and 09:00 AM. Mean height standard deviation score for chronological age (SDS(CA)) was -0.8+/-1.1, significantly (p < 0.01) less than the mean target height SDS of -0.1+/-1.1; mean weight SDS was 0.3+/-1.3. Six (35%) subjects (12.2-21.4 years of age) had anemia with hemoglobin concentrations of 10.6 to 11.6 g/dl. Ultrasound examination showed one or more focal hepatic lesions, consistent with an adenoma in 5 (29%) subjects (10.4 to 21.4 y); 16 subjects had glomerular hyperfiltration; and urinary albumin excretion was increased in 2 subjects, ages 15.9 and 21.1 years.

CONCLUSIONS

Long-term continuous glucose therapy with cornstarch, begun in infancy, resulted in mean height 0.7 SDS less than target height. Optimal biochemical control of GSD-I requires meticulous adherence to an individualized dietary regimen that is based on the results of periodic metabolic evaluation and home blood glucose monitoring. Renal glomerular dysfunction and formation of hepatic adenomata remain serious long-term complications.