Varying clinical presentations at onset of type 1 diabetes mellitus in children--epidemiological evidence for different subtypes of the disease?

OBJECTIVE: On the basis of 2121 case observations between 1987 and 1997, we describe the clinical and laboratory characteristics of diabetes mellitus type 1 at its onset. Our objective is to analyze whether clinical presentation follows a uniform pattern or whether there is evidence for different subtypes. RESEARCH DESIGN AND METHODS: Thirty-one pediatric hospitals and one diabetes center in Baden-Wuerttemberg (BW), Germany, participated in this study. The hospital records of 2121 children below 15 yr of age were examined retrospectively. Statistical analysis was done after logarithmic transformation into a normal distribution. RESULTS: The average duration of symptoms was found to be 15.2 d (95% CI (Confidence Intervals) = 14.3-16.1) ranging between 2.0 and 180 d (95% central range). The most frequent symptoms were polyuria and polydipsia; 7.2% presented with altered level of consciousness. The mean blood glucose value was 407.9 mg/dL (95% CI = 400.0-416.0), corresponding to 23.3 mmol/L (95% CI = 22.8-23.8). The median pH value was 7.35 (95% CI = 7.34-7.36), and the median base excess was -5 mmol/L (95% CI =-5 to -4). The younger patients had a shorter duration of symptoms and suffered most frequently from ketoacidosis. CONCLUSIONS: Although the symptoms of diabetes at its onset follow a uniform pattern, the clinical presentation and duration of symptoms indicate that there may be various forms of type 1 diabetes.