Do Transfusions of Packed Red Blood Cells Decrease Renal Function in Adult Sickle Cell Patients?.
Authors: Hagar Robert W. , Hoehner Christine , Vichinsky Elliott 
Published: October 2019

Abstract
Introduction: Transfusions in Sickle Cell Patients are becoming more frequently used for both well established indications (stroke, severe anemia) and other important symptoms possibly related to anemia or the effects of sickle cell disease(severe fatigue, pulmonary hypertension, leg ulcers, recurrent priapism, recurrent bony infarctions, chronic pains, and end organ protection.) The increasing uses of transfusions have not been evaluated for their quantitative effects on renal function, We undertook to exam this relationship retrospectively in our transfused patients.
Patients and Methods: Medical records from 236 adult sickle cell patients followed at Children’s Hospital Research Center Oakland Adult Sickle Cell Center from December 30th, 1984 to July 10th, 2006 were retrieved to evaluate the total amount of transfusions, serum creatinine, and serum ferritin. The observations were divided into 10 equal time segments closely corresponding to years. Laboratory values were averaged for each time period. The total amount of transfusions for each time periods was also recorded. Data was analyzed by t-tests and linear regression as appropriate using STATA9 (StataCorp, College Station, Texas.) The coefficients were reported per 100 cc transfused blood.
Results: Serum creatinine continues to rise in both transfused and non-transfused adult patients. Overall, those patients NOT TRANSFUSED had a creatinine of 0.9 mg/dl compared to TRANSFUSED patients who had a creatinine of 1.0 mg/dl (p=0.01.) Non-transfused patients had a non-significant increase per year of 0.004 mg/dl. Transfused patients had a 0.09 mg/dl rise per year (0.06 to 0.12, p<0.0001). The mean number of cc of blood transfused for each year ranged from 7873 cc to 10,667 cc with standard deviations of 1500 cc of blood. The serum ferritin differed as expected between nontransfused (683 ng/ml) and transfused (2879 ng/ml) patients. The rate of increase per year differed from a non-significant rise of 96 ng/ml in the non-transfused patients to 237 ng/ml(59 to 414, p=0.009) in our transfused patients. To examine associations among these terms, multiple linear regression was preformed with interactive terms for years of transfusion and amount of blood transfused, and with years of transfusions and average ferritin per year. The most significant variable for increasing serum creatinine was the number of years a patient was on transfusions.
Discussion: Transfusions are used in sickle cell patients for many unevaluated indications, including end organ protection. The overall rise in creatinine in our transfused, but not in non-transfused, patients is surprising. Although this association cannot be considered causal in this retrospective study and could have other explanations not captured by our data,, further investigation seems warranted to see if transfusions themselves may be harmful over years to renal function in sickle cell patients.
Conclusion: Transfusions may be responsible over years for declining renal function in adult sickle cell patients. This finding needs to be investigated in prospective studies.
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