|Analisis coste-efectividad de la automonitorizacion de la glucosa sanguinea en diabeticos tipo 2 [Cost-effectiveness analysis of self-monitoring of blood glucose in type 2 diabetics]
|Clua Espuny J L, Puig Junoy J, Queralt Tomas M L, Palau Galindo A
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.
The self-monitoring of capillary blood glucose (MBG) by Type 2 diabetes patients using reagent strips was studied.
Economic study type
The study population included patients with Type 2 diabetes.
The setting was primary care. The economic study was carried out in Catalonia, Spain.
Dates to which data relate
The effectiveness and resource use data were gathered between 1995 and 1997. The prices were estimated for 1995 to 1997.
Source of effectiveness data
The effectiveness data were derived from a single study.
Link between effectiveness and cost data
The costing was carried out retrospectively on the same sample of patients as that used in the effectiveness analysis.
Power calculations were conducted to determine the sample size appropriate for the study question. The patients were selected through systematic sampling. The study included 286 patients in the MBG group and 311 patients in the no-MBG group. The mean age was 63.7 years in the MBG group and 69.86 years in the no-MBG group.
This was a retrospective case-control study and the effectiveness data were derived from the local health registry. The study was conducted in seven health districts in the region of Tortosa in Catalonia, Spain. The patient data were retrospectively assessed for a period of one year.
Analysis of effectiveness
All of the patients included in the study were accounted for in the analysis. The main effectiveness measure was the number of diabetic patients with good or acceptable metabolic control over one year. This was defined according to the recommendations of the Spanish study group on diabetes in primary care (GedapS). Such recommendations included the threshold values for haemoglobin (Hb) A1c, cholesterol, triglycerides, arterial pressure and cigarette consumption. A partial indicator of effectiveness considered only the HbA1c levels. Compared with patients in the no-MBG group, the patients in the MBG group were significantly younger, had diabetes for a shorter period, lower arterial pressure, and a higher prevalence of nephropathy and left ventricular hypertrophy. In addition, they had less visits, used less oral hypoglycaemics, and used more insulin.
The proportion of diabetic patients with a good or acceptable metabolic control was 27.9% in the MBG group and 29.7% in the no-MBG group, (p=0.9517).
The partial effectiveness was 65.8% in the MBG group and 68.7% in the no-MBG group. The HbA1c levels were not statistically different between the study groups.
The analysis showed that 78% of the whole patient sample were in the conditions defined by the GedapS as patients who should use MBG as a priority, but only 42.5% did actually use it.
The effectiveness analysis showed that the population of diabetics included in the analysis under-used the ideal coverage, as defined by the recommendations of the GedapS. The use of reagent strips did not have a statistically significant impact on patient metabolic control.
Measure of benefits used in the economic analysis
The benefit measure was the proportion of diabetic patients with good or acceptable metabolic control. It was estimated in the effectiveness analysis.
The costs included in the analysis were for the reagent strips, physician visits and diagnostic tests. The drug costs were not considered. The costs to be included in the analysis were selected on the basis of items suggested by the European NIDDM Policy group in 1989. The costs were estimated using Spanish public prices. The cost/resource boundary was that of the local health district. The unit costs were not reported separately from the quantities of resources used. The hypothetical consumption of reagent strips (according to the GedapS criteria) was also estimated. The costs were not discounted, although a 3-year period was considered in the analysis. The resource use was assessed for 1995 to 1997. The price year was 1997.
Statistical analysis of costs
No statistical analysis of the costs was carried out.
The indirect costs were not included in the study.
No sensitivity analysis was performed.
Estimated benefits used in the economic analysis
See the 'Effectiveness Results' section.
The total costs of reagent strips in the overall sample were Pta 24,670 in 1995, Pta 36,166 in 1996, Pta 48,614 in 1997, and Pta 113,695 under ideal coverage.
The average costs in the sample of patients using MBG were Pta 15,734 in 1995, Pta 14,449 in 1996, Pta 18,073 in 1997, and Pta 22,119 under ideal coverage.
The incremental costs (total costs of MBG divided by the number of new MBG users) were Pta 12,295 in 1996, Pta 66,570 in 1997, and Pta 26,573 under ideal coverage.
Synthesis of costs and benefits
The costs and the benefits were combined through an average cost-effectiveness analysis. The cost for patients with a good or acceptable metabolic control was Pta 210,789 in the MGB group and Pta 162,019 in the no-MBG group in 1995. The corresponding costs were Pta 199,881 (MGB group) and Pta 161,971 (no-MBG group) in 1996, Pta 213,148 (MGB group) and Pta 162,051 (no-MBG group) in 1997, and Pta 78,904 (MGB group) and Pta 54,682 (no-MBG group) under ideal coverage.
Under actual conditions, the option of funding self-monitoring of blood glucose (MBG) was not cost-effective compared with no-MBG in the health district of Tortosa.
CRD COMMENTARY - Selection of comparators
The authors compared the study intervention with no-MBG, as the aim of the study was to assess the active value of MBG. You should decide whether it is a widely used health intervention in your own setting.
Validity of estimate of measure of effectiveness
The study used a retrospective case-control study. The number of sites where the study was conducted was reported and power calculations were conducted. The study sample was representative of the study population. However, the study groups were not comparable at baseline. The study results may have been affected by both bias and confounding factors, and also the lack of randomisation in the allocation of the patients to the study groups. These issues tend to affect the internal validity of the analysis.
Validity of estimate of measure of benefit
The benefit measure used in the analysis was the proportion of diabetic patients with good or acceptable metabolic control. It was derived directly from the effectiveness analysis. Quality of life issues were not discussed.
Validity of estimate of costs
The costs relevant to the local health authority were included in the analysis. The drug costs were not estimated, but the authors discussed the reasons for their exclusion. The unit costs and the quantities of resources were not reported separately. The costs were treated deterministically and no sensitivity analyses were conducted. A single price year was not considered and discounting was not applied, although the costs were incurred over three years. The costs were somewhat specific to the study setting.
The authors compared their findings with those from other studies. However, they did not address the issue of the generalisability of the study results to other settings. Consequently, the external validity of the analysis was quite low since the data on both cost and effectiveness were fairly specific to the study setting. The study referred to a sample of patients with Type 2 diabetes and this was reflected in the conclusions of the analysis.
Implications of the study
The efforts of the public provider of health care services should be aimed at reaching the ideal coverage in the population of patients with Type 2 diabetes, especially since it is not easy to obtain the standards of metabolic control suggested by the GedapS.
Clua Espuny J L, Puig Junoy J, Queralt Tomas M L, Palau Galindo A. Analisis coste-efectividad de la automonitorizacion de la glucosa sanguinea en diabeticos tipo 2. [Cost-effectiveness analysis of self-monitoring of blood glucose in type 2 diabetics] Gaceta Sanitaria 2000; 14(6): 442-448
Subject indexing assigned by NLM
Aged; Blood Glucose Self-Monitoring /economics /utilization; Cost-Benefit Analysis; Diabetes Mellitus, Type 2 /blood /drug therapy; Humans; Insulin /therapeutic use; Middle Aged; Reagent Strips /economics; Retrospective Studies
Date bibliographic record published
Date abstract record published