The influence of long-term therapy with the insulin pump (CSII) in patients with type 1 diabetes mellitus on metabolic compensation and on the incidence of hypoglycaemia. Comparison with intensified conventional insulin therapy (MDI)

The principal objective of this paper is to verify, in clinical practice, the long-term affect (7 to 8 year follow up) and safety of insulin pump treatment in type 1 diabetes mellitus patients and to compare the results for diabetes compensation in patients treated with the insulin pump with a control group of patients treated with intensified insulin therapy using the MDI (multiple daily injection) method.


Patient sample and method:
We followed up 35 patients treated with the insulin pump and 35 patients in the control group. We evaluated the monitored parameters for both patient groups at the beginning and at the end of the follow up period. With respect to glycated haemoglobin, we evaluated the results on a yearly basis, and also on year by year changes. We assessed the incidence of hypoglycaemia in both groups on a yearly basis. The following aspects were considered in order to determine the level of statistical significance of the different parameters: 1. we compared the initial state with that seen at the end of the follow up, 2. we analysed the year by year changes in glycated haemoglobin, 3. we compared the patients treated with the insulin pump with those in the control group. Diabetes compensation was evaluated on the basis of measurement of glycated haemoglobin and calculation of glycaemia. Comparison of the incidence of hypoglycaemia was done for all hypoglycemic events and then separately for severe hypoglycaemia. Also evaluated were changes in weight and in insulin dose in 24 hours.

Results:
The group of patients treated with the insulin pump recorded a dramatic decrease in glycated haemoglobin in the course of the follow up, p < 0.001, and also in average glycaemia, p < 0.001. In the control group only a transitory significant decrease of HbA_1c, p < 0.05, was recorded in the first and second year of follow up, later the result was insignificant, i.e. p > 0.05, as compared with the initial state. In this group of patients, no significant improvement in average glycaemia, p > 0.05, was recorded when compared with the initial state. Comparison of the two groups of patients showed that HbA_1c, p < 0.001, and average glycaemia, p < 0.001, were worse with statistical significance in patients treated with the insulin pump at the beginning of the follow up. At the end of the follow up period, there was no significant difference between the two groups in terms of glycated haemoglobin, p > 0.05, but a statistically significant difference was recorded in average glycaemia, p < 0.001, in favour of the group of patients treated with the insulin pump. The use of the insulin pump resulted in a statistically significant decrease in the incidence of severe hypoglycaemic events as compared with the control group, p = 0.010. This decrease was reflected in the measured parameters from the third year of the study to the end of follow up. However, at the beginning of the study and in the first and second years of follow up there was no statistically significant difference between the two groups in terms of incidence of severe hypoglycaemic episodes, p > 0.05. No statistically significant difference between the two groups was recorded in the incidence of all hypoglycaemic episodes from the beginning of the follow up to its end, p > 0.05. In both groups of patients, a statistically significant gain in weight was seen from the beginning of the study to the end of the follow up period, however, its statistical significance was lower (p < 0.05) in the group of patients treated with insulin pump than in the control group (p < 0.001). We proved a statistically significant decrease in daily insulin dose (p < 0.001)was required in the group of patients treated with insulin pump, whilst no statistically significant change in the dose was recorded in the control group (p > 0.05).

Conclusion:
In the course of the follow up, we proved that treatment with the insulin pump in type 1 diabetes is more beneficial to patients than MDI treatment. This was reflected by both better compensation of diabetes and a lower incidence of severe hypoglycaemic episodes.

Keywords: type 1 diabetes mellitus; insulin pump; diabetes compensation; glycated haemoglobin; average glycaemia; hypoglycaemia