Optimal hyperglycemia thresholds in patients undergoing chemotherapy: a cross sectional study of oncologists’ practices

Abstract Purpose Neither the United States nor the European oncology guidelines include details for appropriate management of hyperglycemia in cancer patients. The aim was to identify fasting and random blood glucose thresholds, and hemoglobin A1c (HbA1c) targets used by oncologists in clinical practice when managing hyperglycemia in patients with cancer undergoing chemotherapy. Methods This national, cross sectional study utilized a questionnaire to collect oncologists’ perceptions about optimal blood glucose thresholds and HbA1c targets in patients with cancer undergoing chemotherapy. Descriptive statistics were calculated to summarize glucose thresholds, HbA1c targets, and sample characteristics. Responses to an open-ended question about oncologists’ approach to hyperglycemia management were analyzed via thematic analysis using an inductive approach. Results Respondents ( n = 229) were on average 52.1 years of age, 67.7% men, and 91.3% White. For patients without diabetes but experiencing hyperglycemia, oncologists targeted lower and upper fasting blood glucose levels between 75-121 mg/dL and 105-135 mg/dL, respectively. For patients with diabetes, the targets for lower and upper fasting blood glucose levels ranged between 100-130 mg/dL and 128-150 mg/dL, respectively. Fasting blood glucose (95.6%) and HbA1c (78.6%) were the most commonly used clinical indicators to consider chemotherapy dose reduction, delay, or discontinuation due to hyperglycemia in patients receiving chemotherapy with curative intent. Among those receiving palliative intent chemotherapy, the preferred clinical parameters were random blood glucose (90.0%), patient-reported blood glucose readings (70.7%), continuous glucose monitoring readings (65.1%), and patient-reported symptoms of hyperglycemia (65.1%). Three main themes emerged about oncologists’ approach to hyperglycemia management: 1) identification of high-risk patients; 2) need for early identification, screening, and diagnosis of hyperglycemia; and 3) multiple hyperglycemia management strategies. Conclusion Oncologists reported a wide variation of target blood glucose ranges considered appropriate in patients undergoing chemotherapy. Lack of clear guidance for hyperglycemia management during chemotherapy in the United States may be contributing to a lack of consistency in clinical practice.