PHILADELPHIA—Blood transfusions can provide pain relief in adults with sickle cell disease (SCD) who have failed treatment with hydroxyurea, a pilot study suggests.
Patients had fewer visits to the emergency department (ED) and fewer hospital admissions for pain control after they received chronic transfusions for pain prophylaxis than they did prior to receiving transfusions.
Matthew S. Karafin, MD, of the Blood Center of Wisconsin in Milwaukee, presented these results at the AABB Annual Meeting 2014 (abstract S42-030G).
“Pain in adults with sickle cell disease is probably one of the most important things that we deal with in our clinics,” he began. “It is the leading cause of morbidity in this population.”
Dr Karafin also noted that adults with SCD seem to experience pain differently from children, reporting more of a constant pain, as opposed to the episodic pain observed in kids. And although previous studies have suggested that transfusions do provide pain relief in SCD, most of those studies have focused on children.
So Dr Karafin and his colleagues set out to determine the impact of prophylactic transfusions on the rate of serious pain episodes in adults with SCD. The team retrospectively analyzed a cohort of patients who received chronic transfusions at 3- to 8-week intervals from January 2009 to October 2013.
The researchers defined chronic transfusions as receiving blood—either simple transfusions or red cell exchanges—in an outpatient setting 3 days a week with the goal of controlling hemoglobin (Hb) S percentage, maintaining it at less than 30%.
Patients had to have at least 1 ED or hospital visit for severe pain per month prior to starting transfusions, they were required to have failed hydroxyurea therapy, and they had to have at least 3 months both on and off chronic transfusions. The patients could have no other reason for receiving chronic transfusions (ie, no previous stroke).
So the study included 17 patients, 12 of whom were female. Fifteen (88.1%) had Hb SS disease, and 2 had Hb SC disease. Their median age was 26 (range, 20-54).
“We were able to record 541 total ED admissions over the study period and 404 total hospital admissions,” Dr Karafin said. “The median study evaluation period pre-transfusion was about 3.5 years, and we were able to study [patients for] a median of more than a year for the post-transfusion protocol period.”
Dr Karafin also noted that most of the patients were not transfusion-naïve, but they received significantly more units after being placed on the transfusion protocol.
The median number of red cell units received per 100 days was 1.2 (range, 0-7.2) pre-transfusion and 10.2 (range, 6.7-24.3) post-transfusion (P=0.0003). Nine of the patients received simple transfusions, and 8 received red cell exchanges.
There was a significant difference in the median Hb S pre- and post-transfusion—79% (range, 26.5%-89.6%) and 30.2% (range, 10.9%-57.4%), respectively (P=0.0003).
But there was no significant difference in median ferritin levels—1128.2 ng/mL (range, 65.4-11,130) and 2632.8 ng/mL (range, 16.7-8023.6), respectively (P=0.18). Dr Karafin said this could be explained by the fact that patients were not transfusion-naïve prior to starting the protocol.
Similarly, the median new alloantibody rate per 100 units was 0 both pre- and post-transfusion. This may be due to the fact that all patients received C-, E-, and KEL-matched blood, as well as the freshest available units, Dr Karafin said.
He and his colleagues also found that the median ED admission rate was significantly lower post-transfusion compared to pre-transfusion—0.79 (range, 0-6.6) and 2 (range, 0.4-11) visits every 100 days, respectively (P=0.04).
Thirteen patients (76.5%) had a reduced ED visit rate after chronic transfusion, and there was a 60.5% reduction in the ED visit rate overall.
Likewise, the median hospital admission rate decreased from 1.7 per 100 days (range, 0.05-5.8) pre-transfusion to 1.3 per 100 days (range, 0.2-3.2) post-transfusion (P=0.004).
Fifteen patients (88.2%) had reduced hospital admissions after chronic transfusion, and there was a 20.3% reduction in hospital admissions overall.
Dr Karafin noted that this study had a number of limitations, including a small number of patients, its retrospective nature, and the fact that it was conducted at a comprehensive SCD clinic.
“However, limitations aside, we found significant evidence to support that the findings observed in children seem to be similar in the adult population,” he said.
Namely, chronic transfusions can prevent serious pain episodes in adults with SCD who have failed treatment with hydroxyurea.
