|Continuous subcutaneous insulin infusion (CSII) in children and adolescents with chronic poorly controlled type 1 diabetes mellitus
|Steindel B S, Roe T R, Costin G, Carlson M, Kaufman F R
This is a critical abstract of an economic evaluation that meets the criteria for inclusion on NHS EED. Each abstract contains a brief summary of the methods, the results and conclusions followed by a detailed critical assessment on the reliability of the study and the conclusions drawn.
Continuous subcutaneous insulin infusion using the MiniMed (Sylmar, CA) CSII system.
Type of intervention
Secondary prevention, treatment.
Economic study type
Children and adolescents with poorly controlled diabetes for 2 - 7 years. Poor control was defined as at least 2 episodes of diabetic ketoacidosis per year, chronically elevated glycosylated haemoglobin levels and widely fluctuating blood glucose levels.
Children's Hospital Los Angeles Diabetes Center, USA. The cost analysis referred to the same setting.
Dates to which data relate
No dates were given in the text.
Source of effectiveness data
The evidence was based on a single study.
Link between effectiveness and cost data
Costing was undertaken on the same patient sample as that used in the effectiveness study. However it was not made clear whether costing was undertaken prospectively or retrospectively.
The sample was non-random. Six patients were included in the study aged between 8 years 6 months and 16 years 10 months. It was not stated whether the six patients studied constituted the total number of poorly controlled child and adolescent diabetic patients under the care of the Children's Hospital Los Angeles Diabetes Center, whether any patients were approached who refused to participate or on what grounds the sample was chosen.
A single centre, before and after study. Patients were followed for 1 year before and 1 year after the intervention. No loss to follow up was stated.
Analysis of effectiveness
The analysis was based on six patients who all completed the study. It was not stated whether there were any others who failed to complete the year of monitoring. Primary outcomes measured were the number of hospitalisations due to diabetic ketoacidosis per year; HbA1c levels, microalbumin levels, cholesterol levels, insulin units used per day, growth per year and number of convulsions per year.
Total diabetic ketoacidosis admissions fell from 31 pre-CSII to 10 post-CSII. The means fell from 5.2 (standard deviation 4.6) to 1.7 (standard deviation 0.7). The p value was 0.031. Confidence intervals were not given. The remaining results for primary outcomes showed no statistical significance at the 95% level. Adverse effects mentioned were firstly pump malfunction, which occurred twice. This led to ketoacidosis incidents that are included in the general post CSII results above. Secondly, cellulitis at needle insertion sites occurred in 4 patients a total of 11 times. This was a minor adverse effect requiring outpatient treatment only.
Hospital admissions due to ketoacidosis showed a significant decrease. Adverse effects were minimal. The use of CSII in poorly controlled children and adolescents was a viable treatment option.
Measure of benefits used in the economic analysis
Primary outcomes measured were the number of hospitalisations due to diabetic ketoacidosis per year; HbA1c levels, microalbumin levels, cholesterol levels, insulin units used per day, growth per year and number of convulsions per year.
Costs measured covered the cost of the pumps ($4000) and the cost of disposable supplies ($85 per month). Hospital costs were included and an overall cost per patient was given for the year pre-CSII and the year post-CSII. No other breakdown was given and no prices or quantities were given, but it was apparent from the figures that either a day's hospitalisation has not been charged at a uniform rate or that other costs were included in the total, but not explained. Dates of collection of costs were when the expenditure occurred and no allowance has been made for rising prices. The cost of outpatient care was specifically excluded on the grounds that this did not change before and after the use of the pump.
Statistical analysis of costs
Mean costs, standard deviations and p-values were reported.
No sensitivity analysis was carried out.
Estimated benefits used in the economic analysis
Total diabetic ketoacidosis admissions fell from 31 pre-CSII to 10 post-CSII. The means fell from 5.2 (standard deviation 4.6) to 1.7 ( standard deviation 0.7). The p value was 0.031. Side effects were not considered relevant in the costing.
The total costs pre-CSII were $175,963 and post-CSII were $76,572. The mean costs per patient were pre-CSII $29,327 (standard deviation $20,819) and post-CSII were $12,762 (standard deviation $5431). The p value was 0.047. Costs ranged from $8671 to $69,180 pre-CSII and from $6807 to $20,245 post-CSII. No discounting was carried out. Costs of some adverse effects, (cellulitis at needle insertion sites), were not included since these were treated by oral antibiotics as outpatients. Other adverse effects led to diabetic ketoacidosis with hospitalisation and were included in the overall costs.
Synthesis of costs and benefits
A synthesis was not carried out since the intervention was the dominant strategy.
During the year following the intervention fewer hospitalisations were required and fewer days in hospital were needed. The costs were less and there were minimal adverse effects. Numbers were too small for other measures to show significance and a randomised study with greater numbers of patients is recommended. CSII may be a viable treatment option for children and adolescent patients with chronic poor glycemic control secondary to brittle diabetes or poor adherence to diabetic regimen.
The study sample size was too small to make generalisations from and the study design, without randomisation and with no clear description of the sample selection, was not good. There was no clear breakdown of costs and without quantities and prices it is impossible to generalise from this study. No attempt was made to cost outpatient visits or telephone contacts. These formed a high proportion of the care of diabetes patients and it was not demonstrated that the same costs apply under both regimes.
Steindel B S, Roe T R, Costin G, Carlson M, Kaufman F R. Continuous subcutaneous insulin infusion (CSII) in children and adolescents with chronic poorly controlled type 1 diabetes mellitus. Diabetes Research and Clinical Practice 1995; 27(3): 199-204
Subject indexing assigned by NLM
Adolescent; Albuminuria; Child; Cholesterol /blood; Diabetes Mellitus, Type 1 /blood /drug therapy /physiopathology; Diabetic Ketoacidosis /epidemiology; Growth; Hemoglobin A, Glycosylated /analysis; Hospitalization; Humans; Insulin Infusion Systems; Length of Stay; Retrospective Studies; Seizures /epidemiology /prevention & control
Date bibliographic record published
Date abstract record published