Effect of dietary interventions in the maintenance of normoglycaemia in glycogen storage disease type 1a: a systematic review and meta-analysis

Background: Untreated glycogen storage disease (GSD)-1a patients experience hypoglycaemia and growth retardation. The present study examined the effects of dietary interventions on the maintenance of normoglycaemia.

Methods: Clinical trials were identified from EMBASE (January 1980 to November 2011), MEDLINE (January 1948 to November 2011) and the Cochrane Central Register of Controlled Trials (2011, Issue 4). The intermittent administration of uncooked cornstarch was compared with: (i) continuous nocturnal feeding of dextrose; (ii) modified uncooked cornstarch; and (iii) dextrose and an uncooked cornstarch-dextrose mixture. One author extracted the data, and assessed the trial eligibility and risk of bias. Quality assessment and data extraction were conducted and checked independently.

Results: Of 41 articles retrieved, five controlled trials (49 participants) were identified with follow-up at 2 days to 14 years. Results from three nonrandomised controlled trials comparing uncooked cornstarch with continuous nocturnal feeding of dextrose were pooled in a meta-analysis based on a fixed-effect model. Twenty-six participants (three trials) receiving uncooked cornstarch showed a significant increase in blood glucose concentration: mean difference (MD) 0.62 mmol L(-1) [95% confidence interval (CI) = 0.23-1.00] (P = 0.002), 21 (two trials) increased serum insulin: MD 62.37 pmol L(-1) (95% CI = 32.19-92.55) (P < 0.0001) and 22 (three trials) increased plasma total cholesterol: MD 0.68 mmol L(-1) (95% CI = 0.17- 1.20) (P = 0.01) compared to continuous nocturnal feeding of dextrose. Twenty-eight subjects (three trials) showed decreased plasma lactate after nocturnal feeding: MD -0.42 mmol L(-1) (95% CI = -0.58 to -0.25) (P < 0.00001).

Conclusions: Short- to long-term overnight intermittent administration of uncooked cornstarch prevents nocturnal hypoglycaemia in GSD-1a children more effectively than continuous nocturnal feeding of dextrose.