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Dawn Phenomenon and Somogyi Effect in IDDM

1989; American Diabetes Association; Volume: 12; Issue: 4 Linguagem: Inglês

10.2337/diacare.12.4.245

1935-5548

Judith Stephenson, Guntram Schernthaner,

Diabetes Treatment and Management

We examined the clinical relevance of a rise in fasting blood glucose (BG) between 0300 and 0600 in 97 patients with insulin-dependent diabetes mellitus (IDDM) receiving sequentially conventional (CT) and basal-bolus (BBIT) insulin therapies and assessed the impact of one potential causal factor, i.e., posthypoglycemic hyperglycemia, with 231 BG profiles (97 during CT, 134 during BBIT) in which BG was measured every 3 h over a 24-h period. A rise in BG between 0300 and 0600 occurred in 157 of 231 (68%) profiles. The mean magnitude of this rise was 56 ±39 mg/dl and was lower (P < .05) during BBIT (48 ± 35 mg/dl, n = 97) than CT (62±43 mg/dl, n = 97). A dawn rise (between 0300 and 0600) >50 mg/dl occurred in 40 of 97 (41%) profiles during CT and 26 of 97 (27%) during BBIT (P < .05). When all profiles were grouped according to the magnitude of this rise in BG, the mean daytime BG (from 0900 to 1800) was higher (P < .05) after an 0300–0600 BG rise >50 mg/dl compared with groups of profiles showing either a fall in BG or a rise <50 mg/dl; a rise in BG between 0300 and 0600 correlated (r = .38, P < .0001) with the subsequent mean daytime BG. Nocturnal hypoglycemia (BG <60 mg/dl) recorded at 2400 and/or 0300 occurred in 57 of 231 (25%) profiles. After nocturnal hypoglycemia, the highest BG recorded before breakfast was only 215 mg/dl, and the mean BG at 0600 was considerably lower (P < .0001) in profiles showing at least one episode of nocturnal hypoglycemia (116 ± 45 mg/dl, n = 57) compared with all profiles in which no nocturnal hypoglycemia was detected (174 ± 85 mg/dl, n = 174). In addition, postbreakfast BG levels at 0900 were lower (P < .0001) after nocturnal hypoglycemia (171 ± 87 mg/dl, n = 57) than when no nocturnal hypoglycemia was detected (211 ± 91 mg/dl, n = 174). We conclude that a dawn rise in BG commonly occurs in IDDM patients receiving either CT or BBIT. A dawn BG rise >50 mg/dl may lead to significant exacerbation of daytime hyperglycemia. Nocturnal hypoglycemia does not contribute to morning hyperglycemia, but conversion from CT to BBIT can achieve a modest reduction in the frequency and magnitude of an early-morning rise in BG.