Background: Hyperglycemia is a common, but not well-characterized side effect of glucocorticoid treatment.
Aim: To study the effect of pulse dexamethasone treatment on carbohydrate metabolism among multiple myeloma patients.
Material/subjects and methods: A randomized crossover observational study in a teaching hospital with nine myeloma patients (one male, two with known type 2 diabetes (KDM), mean age 69.0 ± 6.7 years) were investigated using a standard 75 g Oral Glucose Tolerance Test (patients without KDM) and a 3-day continuous glucose monitoring (CGM--all patients) during and between dexamethasone cycles.
Results: During dexamethasone treatment patients had elevated 2-h postload glucose (12.8 ± 4.7 vs. 8.7 ± 3.2 mmol/L, P = 0.024) but similar fasting glucose (6.3 ± 1.4 vs. 5.1 ± 0.5 mmol/L, P = 0.112). Estimated hourly mean interstitial glucose values based on linear mixed models showed an increase of 0.03 [SE 0.01] mmol/L per hour from 5.0 [0.4] in patients without KDM and followed a quadratic curve from 5.0 [0.4] mmol/L at midnight to 7.5 [0.5] mmol/L at 12:00 h in patients with KDM during control periods. During dexamethasone treatment glucose was similar to control periods between 02:00 and 12:00 h in the non-KDM group, where they followed a cubic trajectory from 5.3 [0.4] mmol/L at 04:00 h to 7.3 [0.4] mmol/L at 18:00 h. In contrast, interstitial glucose was increased by at least 7.9 [0.3] mmol/L throughout the day in KDM patients during dexamethasone treatment and increased from 13.6 [0.5] mmol/L at midnight to 17.5 [0.5] mmol/L at 17:00 h.
Conclusions: During pulse steroid therapy of myeloma patients without KDM afternoon and evening glucose measurements may be the optimal tools to characterize glucose metabolism.