The functions use creatinine and albumin, which default to standard international units of µmol/l and g/l, but can be used with US units (mg/dl and g/dl) by setting the optional Units parameter to "US" or by calling any of the wrapper functions using US units by default: soft_US(), p_soft_US() and soft2_US().
#MELD LIVER TRANSPLANT FULL#
There is also a soft2() function to calculate the full SOFT score for patients for whom P-SOFT has already been calculated. The soft() function is a vectorised function to calculate the full 19-variable SOFT score, and the p_soft() function calculates the 14-variable P-SOFT score. There are three key functions in transplantr to calculate SOFT scores. There is also a pre-procurement P-SOFT score which uses the 14 risk factors known before a specific donor liver is offered for transplantation and can be used to risk stratify patients while still on the waiting list. The SOFT score ( 7) aims to predict post-transplant survival in adult liver recipients using 19 risk factors.
#MELD LIVER TRANSPLANT SERIES#
It is a vectorised function and can therefore be applied to a whole series at once, for example in a dplyr pipe: Creatinine and bilirubin are both calculated from their values in µmol/l by default, and can be changed to mg/dl either by setting the optional units parameter to "US" or by using the meld_US() wrapper function instead. The meld() function in transplantr calculates the MELD score with these value assignments taken into account. If the actual level is less than 125, the value 125 is used in the equation, and if more than 137, a fixed value of 137 is assigned. The actual sodium level is only used if sodium is between 125 and 137 mmol/l. The MELD-Na score adds serum sodium levels into the mix if the MELD score is greater than 11. To get the exact MELD score as recommended by UNOS, the part of the equation above in the brackets is rounded to the tenth decimal place before being multiplied by 10. Bilirubin levels less than 1mg/dl are also set to 1, as are INR values of less than 1.
Creatinine 4mg/dl as 4, and patients who are either on CVVH or have been dialysed twice in the week prior to the calculation are assigned a fixed value of 4mg/dl. The original MELD score uses serum creatinine, bilirubin and INR, but cannot be simply calculated as creatinine and bilirubin values are set to specific numbers when outside a set range. There are also two scores using donor characteristics to predict outcome, the DRI (Donor Risk Index) developed in the USA( 9), and the derivative ET-DRI (Eurotransplant Donor Risk Index) adapted to the European donor population, which achieved a c-statistic of and 0.626 in the European population( 10). Another score using a composite of donor and recipient characteristics is the BAR (Balance of Risk) score, which is based on a sample of American and European liver transplants and achieved a c-statistic of 0.7 when predicting patient survival( 8). The SOFT (Survival Outcomes Following Liver Transplantation) Score was developed by at Columbia University to predict recipient survival after liver transplantation( 7). MELD and UKELD are primarily intended to predict waiting list mortality and therefore urgency for transplant, but perform relatively poorly at predicting survival after liver transplant( 4-6). The UKELD score was developed to risk stratify liver transplant recipients in the UK, is based on MELD and adds serum sodium( 3).
The scores have been shown to predict short-term mortality after transhepatic porto-systemic shunt (TIPS) procedure, non-liver transplant surgery in cirrhotic patients, acute alcoholic hepatitis and acute variceal haemorrhage.
It has also been widely used as part of clinical urgency prioritisation in liver transplant matching algorithms, although UNOS changed to the alternative MELD-Na score( 2), which incorporates serum sodium levels, in January 2016. The MELD score was originally developed at the Mayo Clinic to risk stratify elective transhepatic porto-systemic shunt (TIPS) procedures in patients with liver cirrhosis( 1).
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