Introduction Measurement of glucose in blood or urine employing a variety of methods, is used by patients to monitor their diabetes. Although use of quality assurance/ control procedures for these tests is regarded as essential in hospital practice,1 there seems little emphasis on their importance in domiciliary situations. Tighter glycaemic control has been shown to improve prognosis but increase the risk of hypoglycaemia.2 It is, therefore, now even more important that the accuracy of blood glucose meters, used in domiciliary situations, is checked regularly. Method We contacted 390 people with diabetes, identified from our patient medication records and from sales records of blood glucose meters. Patients were interviewed at the beginning of the study and then every three months for a year using a standard, semi-structured interview form, incorporating demographic data, medication details and a scoring chart for estimating proficiency in testing technique and knowledge of diabetes.
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Results One-hundred-and-thirty people completed the study (58 QC), average age 62 years (SD 11.7), 47 per cent female; QC/NQC groups were well matched. During the course of the study the BMI of the QC group rose 0.3kg/m2 from 28.9kg/m2 and the NQC group increased 0.9kg/m2 from 28.7kg/m2.
The median HbA1c of the QC group rose 0.4 from 7.4 but the NQC group increased 1.1 from 7.1 (not significant). All QC subgroups by method of testing (visual and meter blood glucose estimation and urinalysis) and QC subgroups for treatment (metformin and sulphonylurea) showed smaller increases in HbA1c than their corresponding NQC subgroups. The QC insulin sub group (n=12) improved, median HbA1c decreased 0.3 from 8.7 and NQC group (n=11) deteriorated, increasing 0.9 from 8.4.
The average score for technique improved from 62.6 per cent (SD 23 per cent) to 82.2 per cent (SD 17 per cent), (P<0.001) with no difference between QC and NQC. The greatest improvement in technique was seen in the production of a hanging drop of blood where the score improved by 34 per cent.
Ninety-two per cent of participants replied to the patient questionnaire; of these 99 per cent were satisfied/very satisfied and 93 per cent had some gain from the study.
Discussion Attention to patients' home monitoring results can improve glycaemic control.3 Similarly, a Scottish study has found an association between HbA1c results and the number of testing strips dispensed, in people with type I diabetes.4 Our study also focused on this area of home testing and, although it was not powerful enough to demonstrate significant outcomes in the control of diabetes, people in the QC group did better. It is also important to remember that QC procedures are a necessary safety mechanism in any monitoring procedure.1
A community pharmacist can provide effective education in the use of domiciliary diabetes testing equipment and with help from the local pathology laboratory, the pharmacy is a suitable place for ongoing support using a local quality control scheme.
Dixon & Hall Ltd; *North Durham hospital trust
| 1. Blood glucose measurements: reliability of results produced in extra-laboratory areas. London: Department of Health and Social Security; 1987. |
| 2. The diabetes control and complications trial research group. The effect of intensive treatment of diabetes on the development and progression of long-term complications in insulin-dependent diabetes mellitus. N Engl J Med 1993;329:977-86. |
| 3. Wredling R, Adamson U, Ericsson A, Larsson Y, Oestman J. Patients' opinions on diabetic care in relation to glycaemic control. Practical Diabetes International 1996;13:80-2. |
| 4. Evans J, Newton R, Ruta A, MacDonald T, Stevenson R, Morris A. Frequency of blood glucose monitoring in relation to glycaemic control: observational study with diabetes database. BMJ 1999;319:83-6. |