RESUMO
OBJECTIVE: Patients with diabetes are routinely asked to fast for laboratory tests. If not properly prepared, they may be at risk for hypoglycemia, which may result in traffic accidents while driving en route to and from laboratory facilities. We undertook this study to evaluate the magnitude of this overlooked problem, and to evaluate the effectiveness of a prevention program implemented in our clinic. METHODS: A retrospective study consisting of chart reviews and telephone interviews of consecutive hypoglycemic events (blood glucose level < 70 mg/dL). The study cohorts, A and B, were extracted from our central laboratory database. Cohort A (from January 2008-September 2009) consisted of patients prior to--and cohort B (from October 2009-June 2011) subsequent to--the implementation of a prevention program involving blood glucose monitoring and adjustment of antidiabetic medications. Duration of each cohort was 21 months. For the purpose of this article, we use the acronym FEEHD (fasting-evoked en-route hypoglycemia in diabetes) to describe this overlooked form of hypoglycemia. RESULTS: Of a total of 1801 blood glucose test results retrieved, cohort A included a total of 55 hypoglycemic events in 51 patients (4 patients with 2 events each). Cohort B included a total of 23 hypoglycemic events in 22 patients (with 1 patient sustaining 2 events) out of a total of 2561 blood glucose test results retrieved. In cohort A, of 35 patients on antidiabetic medications who recalled fasting or probably fasting, there were 39 hypoglycemic events (2.2% frequency), compared with 18 events (0.7% frequency) in 17 patients in cohort B. This indicates a 68% risk reduction. The frequency of critical hypoglycemia (< 50 mg/dL) was more significantly reduced, from 11 events (0.6%) to 2 events (0.07%), indicating a risk reduction of 88%. CONCLUSION: This study showed a 68% risk reduction of FEEHD with implementation of the prevention program, and an 88% reduction of severe FEEHD (blood glucose level < 50 mg/dL). Reporting on the first prevention program of its kind, this is the first study to evaluate an overlooked safety problem in diabetes management. Clinicians should consider if fasting laboratory tests are in fact necessary, and when ordered, clinicians should properly instruct their patients on adequate blood glucose monitoring and adjustment of antidiabetic medications. We present the guidelines that proved effective in our program to help patients with diabetes and their clinicians avert this potentially harmful complication.