Modified glasgow prognostic score predicting high conversion ratio in opioid switching from oral oxycodone to transdermal fentanyl in patients with cancer pain.

The aim of this study was to identify predictive factors for higher conversion ratio in opioid switching from oral oxycodone to transdermal fentanyl (TDF) in patients with cancer pain. The participants of this study were 156 hospitalized cancer patients who underwent opioid switching from oral oxycodone to TDF at the Affiliated Hospital of Binzhou Medical University between January 1st, 2010 and March 31st, 2014. Patient characteristics, modified Glasgow Prognostic Score (mGPS), daily oxycodone dose, and reasons for opioid switching were retrospectively collected. The effect of variables on the conversion ratio was analyzed by multiple regression analysis to identify the predictive factors for higher conversion ratio in opioid switching from oral oxycodone to TDF. The results showed that the mGPS (odds ratio [OR], 2.358; 95% CI 1.379-4.031; P = 0.002), the reason for opioid switching (OR, 0.497; 95% CI, 0.298-0.828; P = 0.007) and equivalent oral morphine dose (OR, 1.700; 95% CI, 1.008-2.867; P = 0.046) were found to be significant predictors requiring higher conversion ratio in opioid switching. This study indicates that higher mGPS, poor pain control before switching and higher equivalent oral morphine dose are significant predictors of a need for higher conversion ratio in opioid switching from oral oxycodone to TDF. These results could contribute to the establishment of evidence-based medicine in cancer pain relief.