METHODS: A retrospective cohort study was conducted on hospitalised adult COVID-19 patients admitted between June and August 2021 in general COVID-19 wards, treated with methylprednisolone. Clinical outcomes evaluated include in-hospital mortality, thirty-day mortality, clinical efficacy (C-reactive protein (CRP), total white blood cells (TWBC) and oxygen requirement) as well as the safety of methylprednisolone.
RESULTS: Of 278 patients, 1(0.4%) received weight-based dosing of 1 mg/kg/day, 101(36.3%) received weight-based dosing of 2 mg/kg/day, 130(46.8%) received fixed dosing methylprednisolone 250 mg/day and 46(16.5%) received fixed dosing methylprednisolone 500 mg/day. There was a significant difference in in-hospital mortality rates following different methylprednisolone doses whereby in-hospital mortality occurred in 22.5% (n = 23) of patients with 1 or 2 mg/kg/day methylprednisolone, 32.3% (n = 42) with 250 mg/day and 39.1% (n = 18) with 500 mg/day (p = 0.023). On the other hand, no significant difference in thirty-day mortality, clinical efficacy and safety was observed between different dosing regimens (p > 0.05).
CONCLUSION: The use of methylprednisolone weight-based dosing in hospitalised COVID-19 patients should be considered due to the positive outcome associated with lower in-hospital mortality.
METHODS: The warfarin maintenance doses for 140 patients were predicted using the dosing tool and compared with the observed maintenance dose. The impact of genotype was assessed by predicting maintenance doses with prior parameter values known to be altered by genetic variability (eg, EC50 for VKORC1 genotype). The prior population was evaluated by fitting the published kinetic-pharmacodynamic model, which underpins the Bayesian tool, to the observed data using NONMEM and comparing the model parameter estimates with published values.
RESULTS: The Bayesian tool produced positively biased dose predictions in the new cohort of patients (mean prediction error [95% confidence interval]; 0.32 mg/d [0.14-0.5]). The bias was only observed in patients requiring ≥7 mg/d. The direction and magnitude of the observed bias was not influenced by genotype. The prior model provided a good fit to our data, which suggests that the bias was not caused by different prior and posterior populations.
CONCLUSIONS: Maintenance doses for patients requiring ≥7 mg/d were overpredicted. The bias was not due to the influence of genotype nor was it related to differences between the prior and posterior populations. There is a need for a more mechanistic model that captures warfarin dose-response relationship at higher warfarin doses.