OBJECTIVE—To evaluate whether educational messages regarding oral glucose tolerance test (OGTT) indications in laboratory reports increase the number of OGTTs appropriately requested.
RESEARCH DESIGN AND METHODS—The following message was printed on the lab reports of individuals with a fasting plasma glucose (FPG) concentration between 5.5 and 6.9 mmol/l: “A FPG between 5.5 and 6.9 mmol/l is considered abnormal by the American Diabetes Association (impaired fasting glucose). An OGTT is recommended if the patient does not have a diagnosis of diabetes and suffers from conditions associated with an increased risk for having type 2 diabetes (i.e., overweight, high blood pressure, abnormal plasma lipids or family history of diabetes).” The number of educational messages printed was 81,099.
RESULTS—The intervention resulted in a significant increase in the number of OGTTs requested, from 78 ± 19 to 268 ± 48 tests per month. It also resulted in a greater proportion of case subjects that had an abnormal OGTT result.
CONCLUSIONS—Educational messages in laboratory reports aid in the diagnostic workup of hyperglycemia.
There is a significant delay in diagnosing type 2 diabetes. The oral glucose tolerance test (OGTT) is the most sensitive test available (1). Its use has been recommended by several clinical guidelines (2), and it allows an earlier diagnosis of diabetes than fasting plasma glucose (FPG) criteria alone (3). The OGTT should be considered in the presence of an FPG between 5.5 and 6.9 mmol/l. However, it is not frequently requested due to test-related inconveniences and insufficient information regarding the FPG range for which the OGTT is useful. A large percentage of physicians consult laboratory report reference ranges to make clinical decisions (4). Our objective was to evaluate whether the inclusion of educational messages regarding OGTT indications in laboratory reports increases the number of OGTTs appropriately requested.
RESEARCH DESIGN AND METHODS—
The study was done in collaboration with México's largest network of private laboratories (Laboratorio del Chopo). Laboratorio del Chopo consists of 105 offices located in seven cities and is principally used by primary care physicians. The intervention started in February 2006. The following message was automatically printed on the lab reports of all individuals with an FPG between 5.5 and 6.9 mmol/l: “A FPG between 5.5 and 6.9 mmol/l is considered abnormal by the American Diabetes Association (impaired fasting glucose). An OGTT is recommended if the patient does not have a diagnosis of diabetes and suffers from conditions associated with an increased risk for having type 2 diabetes (i.e., overweight, high blood pressure, abnormal plasma lipids or family history of diabetes)” (5).
The number of OGTTs requested from February 2006 through September 2007 was calculated and compared with the number requested from January 2004 through January 2006. The observation period before and after the intervention was extended as much as possible in order to avoid the effect of seasonal variations on the number of requested tests. In addition, this number was compared with the number of requests received for other common laboratory tests (blood count, FPG, blood chemistry panel, and microalbuminuria). The number of OGTTs requested before and after the intervention was compared using the unpaired t test. Additional cost per detected case was estimated by dividing the additional costs that resulted from the intervention by the number of abnormal subjects found.
RESULTS—
The inclusion of the educational message regarding the use of the OGTT resulted in a significant increase in the number of OGTTs requested. During the period of January 2004 through January 2006, the mean number of OGTTs performed per month was 78 ± 19 (range 48–116). The percentage of OGTTs that had an FPG in the impaired fasting glucose range in the 3 months prior was 19.1%. The intervention started in February 2006. The number of educational messages printed was 81,099. The number of OGTTs increased to 268 ± 48 per month (range 148–351) from February 2006 through September 2007 (a 339% increment, P < 0.001) (Fig. 1). After the intervention, the percentage of OGTTs that had an FPG in the impaired fasting glucose range in the 3 months prior increased to 30.4% (P < 0.05 compared with the preintervention observation period). The increase in the number of requested OGTTs was significantly greater than that observed for other laboratory tests. For example, the number of blood counts requested increased in the same time period by only 19% (from 14,564 to 17,363 tests/month). A similar percentage of change was observed for the chemistry panel (+18.3%) and microalbuminuria (+11.5%) tests. The number of OGTT requests increased constantly during the first 3 months and remained stable during the following 13 months (Fig. 1).
Finally, intervention resulted in a greater proportion of case subjects that had an abnormal OGTT. Before the intervention, 27% of the OGTTs had an abnormal result (10.4% diabetes and 16.6% impaired glucose tolerance) (73% had normal glucose tolerance). After the interventions, this percentage was found to have increased to 52.6% (19.1% diabetes and 33.5% impaired glucose tolerance) (47.4% had normal glucose tolerance).
The additional cost per detected case of diabetes was low ($179.78 USD). The amount was even lower for impaired glucose tolerance ($94.04) and for diabetes and impaired glucose tolerance combined ($61.74).
CONCLUSIONS—
Our results demonstrate that the inclusion of educational messages in laboratory reports is a useful approach to help physicians and patients to undergo a complete diagnostic evaluation. Here, we applied this strategy to increase the likelihood of having a diagnostic OGTT in patients at risk for diabetes. The intervention resulted in a 339% increment in the number of requested tests over a 20-month period; 48.5% of the OGTTs had an abnormal result. More importantly, our low-cost intervention allowed the detection of 311 diabetic case subjects and 546 patients with glucose intolerance by means of the performance of an OGTT, a test that has proved to be cost-effective compared with FPG criteria (6). Furthermore, this approach increased the proportion of OGTTs that had an abnormal result. The same technique (i.e., educational messages) could be applied to remind patients and physicians to undergo a yearly lipid profile, microalbuminuria measurements, and eye examinations. In summary, educational messages in laboratory reports aid in the diagnostic workup of hyperglycemia.
References
Published ahead of print at http://care.diabetesjournals.org on 11 February 2008. DOI: 10.2337/dc07-1912.
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