Comparative analysis of post-transfusion increment in platelet counts in patients receiving single donor platelets by apheresis versus random donor platelets

Aims and objectives

The study aimed at comparing and analyzing differences between post-transfusion increment in platelet counts, including ACI, CCI, and PPR in patients receiving SDPs versus RDPs.

Another objective of the study was to analyze the association between CCI and PPR in patients receiving SDPs and RDPs with respect to various diseases.

Setting

The study was conducted in the Department of Immunohematology and Blood Transfusion of our institute after Institutional Ethics Committee approval. A time frame of 2.5 years with sample collection for 18 months from 12^th April, 2023, to 11^th November, 2024, was used. Patients were divided into 2 groups: Group 1 - Patients receiving RDP transfusions Group 2 - Patients receiving SDP transfusions.

Inclusion criteria

All the admitted patients with thrombocytopenia who received RDP or SDP from Blood Center and gave consent for participation were enrolled in the study.

Exclusion criteria

1. Incomplete platelet transfusion due to transfusion reactions

2. Patients discharged or expired before 24 h post-transfusion.

Methods

• After the request form for the required platelet product was received, details (name, age, gender, weight, indication for transfusion, pre-transfusion platelet count) were noted. In the case of RDP, blood center already had the prepared stock which could be issued directly when demanded. Same blood group RDPs were preferred for newborns, children below 10 years of age, pregnant females, females in reproductive age, and multiple-transfused patients.

• For SDP, a voluntary donor, fulfilling the donor selection criteria, and of same blood group as patient was arranged and SDP was prepared by optia spectra apheresis system. On completion of procedure, the SDP prepared was labeled and stored in Platelet Agitator and Incubator at 22–24°C for maximum of 5 days counting the day of collection as day 0.

Post transfusion analysis

2–3 mL of patient’s blood sample was taken in an ethylenediaminetetraacetic acid (EDTA) vial after 6 and 24 h of transfusion. Post-transfusion platelet count was measured by Unicel DxH 800 Coulter Cellular Analysis cell counter System.

Patient’s height, weight, pre and post-platelet counts, and product yield were noted.

Using these values, the following outcome measures were calculated:

1. ACI in platelet count Post-transfusion platelet count−pre-transfusion platelet count

2. CCI in platelets

3. Percentage of platelet recovery

Data handling

Data handling was done using Microsoft Excel Spreadsheet. Two Excel spreadsheets, one for RDPs and one for SDPs, were prepared and the data were converted into sums and means. The data were therein considered according to demographics, diagnosis, and the assigned outcome measures for the transfusions.

Statistical analysis

A statistical comparison between the outcome measures expressed as mean and standard deviation (SD) for pre- and post-transfusion groups was conducted using paired t-test, first for RDP group and then for SDP group. Thereafter, both RDP and SDP groups were statistically compared using unpaired t-test. Furthermore, a Chi-square test was used for to analyze platelet count in both groups with respect to different disease conditions.

A P < 0.05 was considered statistically significant.

Gender

In the SDP group, 59 (60.8%) recipients were males and 38 (39.2%) were females, while in the RDP group, 89 (56.0%) were males and 70 (44.0%) were females. The overall male-to-female ratio was 1.4:1, indicating a moderate male predominance among patients requiring platelet transfusion (P = 0.457).

Age

The age of recipients ranged widely from 2 years to 90 years, with a mean of 51.3 years (SD ± 20.1 years) across both groups (P = 0.174). Age stratification revealed that the largest proportion of recipients (34.0%) were elderly patients (>60 years), followed by middle-aged adults between 41 and 60 years (30.5%), young adults between 18 and 40 years (27.3%), and pediatric patients below 18 years (8.2%). The SDP group had a higher percentage of young adults (34.0% vs. 23.3% in RDP) while the RDP group had more elderly patients (36.5% vs. 29.9% in SDP).

Distribution by clinical departments

The medical intensive care unit accounted for the highest number of transfusions (23.0%), followed by obstetrics and gynecology (16.8%), cardiac care unit (15.6%), and neuro ICU (14.8%) [Figure 1].

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Figure 1:

Clinical department-wise distribution of platelet transfusions. MICU: Medical intensive care unit, NeuroICU: Neurology intensive care unit, OBGY: Obstetrics and gynecology, CCU: Cardiac care unit, EMR: Emergency, Resp MICU: Respiratory medicine intensive care unit, CTVS: Cardiothoracic and vascular surgery, SDP: Single donor platelets, RDP: Random donor platelets

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Primary diagnosis of recipients

Primary thrombocytopenia without any identifiable cause was the most common diagnosis, 28.1% (72/256) of all transfusions. Trauma patients, classified under road-side accidents, constituted the second largest category (14.8%, 38/256) of platelet recipients. Dengue infection, endemic in our region, accounted for 11.7% (30/256). Antenatal care (ANC) cases constituted 10.9% (28/256), with a notably higher proportion in the SDP group (14.4%, 14/97) [Figure 2].

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Figure 2:

Primary diagnosis of recipients. SDP: Single donor platelets, RDP: Random donor platelets, COPD: Chronic obstructive pulmonary disease, LRTI: Lower respiratory tract infection.

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Pre - transfusion platelet counts

The pre-transfusion platelet count, a critical parameter determining the need for platelet support, was comparable between the SDP group (mean 39,226 ± 28,412/μL) and the RDP/group (mean 37,849 ± 27,921/μL; P = 0.708).

Further stratification revealed that 14.4% of SDP recipients and 15.7% of RDP recipients had severe thrombocytopenia (<10,000/ μL), while 18.6% of SDP recipients and 22.6% of RDP recipients had moderate thrombocytopenia (10,000–20,000/μL). The remaining patients had counts above 20,000/μL, suggesting that transfusions were administered either prophylactically before invasive procedures or therapeutically for active bleeding despite only moderate thrombocytopenia.

Transfusion characteristics

In the SDP group, the mean number of units transfused per patient was 1.07 ± 0.26, with only 7.2% (7/97) of patients receiving 2 units. By contrast, the RDP group exhibited much greater variability in dosing, with a mean of 5.24 ± 2.63 units per transfusion and a range of 1–14 units. The majority of RDP recipients (44.7%) received 5–8 units, while 42.8% received 1–4 units, and 12.6% received more than 8 units.

Cases with low CCI and low PPR

Cases with poor platelet increment, defined as CCI <7,500 or PPR <20%, were identified in both groups. In a total of 19 such cases, the SDP group had 6 cases (6.2%) compared to 13 cases (8.2%) in the RDP group.

Factors affecting post-transfusion platelet increments

Clinical diagnosis emerged as a major determinant of transfusion efficacy. Patients with chronic liver disease, extensive burns (>80% BSA), and respiratory conditions (pneumonia, chronic obstructive pulmonary disease (COPD), lower respiratory tract infection [LRTI]) consistently demonstrated lower CCI and PPR values compared to those with primary thrombocytopenia. In both SDP and RDP groups, CCI was reduced by approximately 20–25% in these conditions (P < 0.05) [Table 2].

Pre-transfusion platelet count showed a significant inverse relationship with post-transfusion increments. Patients with severe thrombocytopenia (<10,000/μL) exhibited markedly higher CCI and PPR values compared to those with counts >60,000/μL (P < 0.01) [Table 3].

Among the 19 cases with poor recovery, dengue was the most common underlying condition (4 cases, 21%), followed by thrombocytopenia with malignancy (3 cases, 15.8%). Sepsis-associated conditions (4 cases) collectively accounted for 21% of refractory cases [Table 4].

In the SDP group, patients with burns demonstrated the lowest values (CCI: 11,425 ± 6,234, PPR: 33.86 ± 18.54%), followed with respiratory conditions (CCI: 13,456 ± 6,245, PPR: 37.45 ± 16.82%) and chronic liver disease (CCI: 14,253 ± 5,645, PPR: 39.17 ± 15.42%). A similar pattern was observed in the RDP group, with burn patients showing the poorest response (CCI: 10,852 ± 5,967, PPR: 32.15 ± 17.82%).

Post-transfusion platelet increments

The difference in ACI between the 2 groups was statistically significant. A study done at the tertiary care hospital of South Gujarat also reported significantly higher absolute increments with SDPs (37.3 ± 20.7 × 10³/μL) compared to RDPs (26.0 ± 11.6 × 10³/μL; P = 0.01).^[12]

However, the key insight from our study emerged when these increments were adjusted for patient-specific factors and the number of platelets transfused; the differences between the two products became less pronounced. Another hospital-based study demonstrated comparable CCI in SDP and RDP groups.^[13] The PPR results in our study further corroborate this pattern.

The temporal pattern of platelet increments in our study, with modest decreases from 6 to 24 h, was consistent with normal platelet clearance processes. This pattern aligned with observations in study done on patients with hypoproliferative thrombocytopenia.^[14]

Cases with platelet transfusion refractoriness were predominantly associated with specific clinical conditions, suggesting that disease-related factors rather than product characteristics were the primary determinants of poor increment.

Factors affecting post-transfusion platelet increments

Clinical diagnosis emerged as a major determinant of transfusion efficacy. Patients with chronic liver disease, extensive burns (>80% BSA), and respiratory conditions (pneumonia, COPD, LRTI) consistently demonstrated lower CCI and PPR values compared to those with primary thrombocytopenia likely due to increased platelet consumption, splenic sequestration, or immune-mediated destruction, consistent with a study mentioning clinical factors influencing CCI.^[15]

The inverse relationship between pre- and post-transfusion increments reflects reduced endogenous platelet destruction when baseline counts are low, possibly due to decreased activation of clearance mechanisms or more efficient circulation of transfused platelets in severely thrombocytopenic patients.

Among the 19 cases with poor platelet recovery in our study, dengue was the most common (21.1%), followed by thrombocytopenia associated with malignancy (15.8%). This finding aligns with a study that reported suboptimal increments in dengue, attributed to ongoing immune-mediated platelet destruction and endothelial activation.^[16] The poor increments observed in patients with extensive burns in our study echo findings by various researchers who have documented accelerated platelet consumption and destruction in the setting of severe thermal injury due to wound factors, DIC, and sepsis.^[17,18]

The specific obstetric conditions with poor recovery in our study including pre-eclampsia and post-LSCS have been identified as challenging scenarios for platelet transfusion.

Hence, the comparable efficacy between RDPs and SDPs challenges the longstanding assumptions about the superior clinical benefit of apheresis platelets and provides evidence-based guidance for optimizing platelet transfusion strategies. These findings collectively suggest that the efficiency of platelet transfusions is comparable when appropriately dosed, suggesting that the choice between these products should rather be guided by factors such as patient-specific risks, resource availability, regional preferences, and cost-effectiveness.

Limitations

1. The non-randomized allocation of patients to SDP or RDP groups, based on product availability and physician preference, introduces potential selection bias, although the comparable baseline characteristics between groups mitigate this concern to some extent

2. We did not specifically assess immunological complications such as alloimmunization, which represent important considerations, particularly for patients requiring long-term transfusion support.