KIDNEY transplantation does not result in full renal recovery function, meaning that patients require a range of medications after transplantation, including immunosuppressants. Therefore, careful judgement is still required when prescribing medications for kidney transplant recipients.
Although a few preliminary studies have been performed, the evidence for metformin usage in kidney transplant recipients is lacking. This warrants the need for information on the long-term efficacy and safety of metformin usage in kidney transplant recipients. A novel retrospective cohort study from the department of internal medicine at Seoul National University Hospital, Korea, has revealed that kidney transplant recipients may benefit from using metformin due to its correlation with reduced death-censored graft failure.
The researchers examined the clinical effects of metformin in 1,995 kidney transplant recipients with diabetes, where a total of 1,193 patients used metformin (as defined by using it for more than 90 days), whereas 802 did not. A total of 1,565 patients were diagnosed with pre-transplantation diabetes, while 430 were diagnosed with post-transplant diabetes.
The all-cause mortality and death-censored graft failure (DCGF) were considered as the primary outcomes of the study, whilst metformin use served as the exposure. Survival analyses were performed using multivariable Cox regression, and competing risk analyses were conducted using Fine and Gray models. A time-varying covariate permitted the modelling of changes in metformin use over time.
Despite a correlation between metformin use and a reduced risk for DCGF, there was no observed association with all-cause mortality. Metformin use was linked with a reduction in all-cause mortality risk and DCGF among patients before and after transplantation, as revealed by a subgroup analysis. A correlation between metformin usage and reduced risk of biopsy-proven acute rejection was identified in the post-transplant diabetes group. Overall, an increase in metformin dose was correlated with lower risks of DCGF and biopsy-proven acute rejection.
The findings suggest that metformin can impact patient outcomes and should, therefore, be considered by physicians. However, further randomised controlled trials are required to validate these findings. Future investigations should account for the use of sodium-glucose co-transporter-2 inhibitors and define post-transplant diabetes according to the American Diabetes Association (ADA) criteria.