Abstract
Background
After years of surpluses in numerous blood components in the province of Ravenna, there is now evidence that the increased use of such products is leading to an ever less abundant self-sufficiency. The concern about the possible loss of self-sufficiency, in a province in which the population of donors does not seem to be adequate to compensate for transfusion domands, led us to verify consumption and future prospects in greater detail.
Materials and methods
In order to plan future transfusion needs, past consumption was analysed dividing the population into several age groups. This historical use of blood products was projected into the scenario of the population in years to come to estimate needs and their increases over time.
Results
The use of transfusion products is very different in different age groups, increasing notably with age. Age factor was identified as the most important factor determining blood product consumption.
Discussion
It will, therefore, be the aging of the population that causes an increase in blood product requirements. Projections from the Italian Institute of Statistics considering age groups of the population up to 2051 enable predictions of transfusion needs, in the absence of drastic interventions on the appropriateness of transfusion practices. Considering that the public and private hospitals of Ravenna predominantly admit subjects from its own territory, these predictions appear realistic, provided that new reasons for consumption are not introduced.
Keywords: estimated needs, transfusion appropriateness, demographic projections
Introduction
In recent years there has been a worrying inversion in the province of Ravenna between the collection of whole blood (27,000 units) and its use (28,000 units) passing from a surplus that enabled the province to help other areas that were not self-sufficient in blood products to a slight deficit that, in 2009, necessitated recourse to regional stores.
In order to tackle this problem better, it was considered necessary to try to predict future patterns in blood product requirements by examining trends in past consumption. The aim of this was to foresee future needs and any deficits and make plans together with local and regional clinicians and management figures.
There are literature reports from Finland1, Great Britain2,3 and France4 indicating that the consumption of blood products is not related to the number of residents of a population, but to the population’s composition in terms of age groups, being much greater as age increases. In this study we examined the situation in Ravenna and used projections from the Italian Institute of Statistics (ISTAT) concerning the inhabitants of the province, for every year of age, up to 2051, grouping the inhabitants according to age range in order to predict possible trends in future consumption.
Planning appropriate therapy was the first step towards guaranteeing good practice, in concordance with international guidelines5–23; however, we wanted to determine whether other factors were relevant. Since the time of the soothsayers and Sibyls mankind has always tried to predict the future in moments of crisis in order to face it: in modern times these predictions are entrusted to mathematical calculations and statistics.
Materials and methods
Given that our data confirmed that consumption of blood products increases with age and that about 16% of patients admitted to hospital require transfusions, we analysed overall blood product consumption in 2009 by age group (excluding auto-transfusions and units eliminated). The data on consumption in 2009 are the latest data available and in line with those of the preceding years and, therefore, valid for making projections in the absence of structural interventions on the appropriateness of use of blood products.
These data are related to the corresponding population of the same age group resident in the province in 2009, of the same age group, in order to be able to compare them with the ISTAT data which predict the future population of the province of Ravenna up to 2051, for every year of age. Three scenarios of future needs were delineated in conformity with the ISTAT data24. The ISTAT predictions on the demographic evolution were produced according to internationally recognised standard methods, using the cohort component model. According to this model, the population, taking into account the natural process of aging, changes from one year to the next, as births are added, deaths are subtracted, and migratory movements incorporated (both within and outside the country) - adding immigrants and subtracting emigrants.
All statistical calculations were done using computer programs Microsoft Excel 2002 (Microsoft Corporation, NY, USA) and SPSS (Statistical Package for the Social Science; SPSS Inc., Chicago, IL, USA) version 15 for Microsoft Windows, interpolating interpolating the data with polynomial curves of various degrees in order to determine, from the inflection, the trend (always increasing, destined to plateau or fall). The equation and R2 values are given for every curve.
Results
Situation in 2009
The overall data on transfusions administered by age group are reported in both absolute values and in relation to the population, in Table I, and represented graphically for red blood cells, platelets and plasma consumed per 1,000 inhabitants.
Table I.
Overall data of blood component consumption.
| Age group | Red blood cells | Platelets | Plasma | Inhabitants | Red blood cells/inhabitant | Platelets/inhabitant | Plasma/inhabitant |
|---|---|---|---|---|---|---|---|
| 0–4 | 32 | 0 | 19 | 17,332 | 1,85 | 0,00 | 1,10 |
| 5–9 | 9 | 0 | 0 | 16,106 | 0,56 | 0,00 | 0,00 |
| 10–14 | 7 | 1 | 0 | 14,663 | 0.48 | 0.07 | 0.00 |
| 15–19 | 92 | 36 | 4 | 14,506 | 6.34 | 2.48 | 0.28 |
| 20–24 | 229 | 144 | 29 | 15,550 | 14.73 | 9.26 | 1.86 |
| 25–29 | 140 | 5 | 16 | 19,982 | 7.01 | 0.25 | 0.80 |
| 30–34 | 341 | 33 | 58 | 27,994 | 12.18 | 1.18 | 2.07 |
| 35–39 | 554 | 53 | 40 | 32,013 | 17.31 | 1.66 | 1.25 |
| 40–44 | 658 | 124 | 105 | 32,821 | 20.05 | 3.78 | 3.20 |
| 45–49 | 428 | 39 | 40 | 29,469 | 14.52 | 1.32 | 1.36 |
| 50–54 | 698 | 69 | 69 | 25,715 | 27.14 | 2.68 | 2.68 |
| 55–59 | 1,242 | 194 | 109 | 23,877 | 52.02 | 8.12 | 4.57 |
| 60–64 | 1,778 | 300 | 162 | 23,765 | 74.82 | 12.62 | 6.82 |
| 65–69 | 2,213 | 353 | 213 | 22,064 | 100.30 | 16.00 | 9.65 |
| 70–74 | 3,719 | 362 | 194 | 22,255 | 167.11 | 16.27 | 8.72 |
| 75–79 | 4,566 | 320 | 243 | 18,815 | 242.68 | 17.01 | 12.92 |
| 80–84 | 4,920 | 144 | 218 | 15,026 | 327.43 | 9.58 | 14.51 |
| >85 | 5,480 | 79 | 136 | 13,776 | 397.79 | 5.73 | 9.87 |
| Total | 27,106 | 2,256 | 1,655 | 385,729 | 70.27 | 5.85 | 4.29 |
The data on red cells show a clear increase in consumption, approximating a third order curve with a R2>0.99, which rises rapidly after 50 years (Figure 1). This trend is similar to that found in Finland1 and in a study in Great Britain2, which reported similar rates per 1,000 inhabitants, and in another subsequent study in Great Britain3 in which the analysis was also extended to platelets and plasma. The same trend in the number of transfused patients was found in France4.
Figure 1.
Red cells used/1,000 inhabitants/age group.
We also studied the consumption of platelets (Figure 2), which was found to oscillate from 15 years onwards with two peaks at 20–24 and 75–79 years old, followed by a decrease with advancing age; this is a sixth order curve with a R2=0.90. The trend is similar to that found in Great Britain3.
Figure 2.
Platelets used/1,000 inhabitants/age group.
With regards to plasma (Figure 3), the consumption increased up to 80–85 years old and then fell (fifth order curve, R2=0.96). The trend is also similar to that found in Great Britain3.
Figure 3.
Plasma used/1,000 inhabitants/age group.
Predictions for the future
Predictions were made for each age group, although only the total data are represented in the figure, and according to three different scenarios, high, central and low, of which only the middle one is considered in the following. This central scenario has a linear trend (Figure 4), like the high one, whereas the low scenario could be interpolated with a parabolic curve with a downwards inflection, indicating that the increase in consumption is not destined to be indefinite.
Figure 4.
Plasma used/1,000 inhabitants/age group.
Table II, using the ISTAT forecasts for the central scenario, shows the estimated needs for blood components by decade.
Table II.
Estimated needs according to the central ISTAT scenario.
| Year | 2011 | 2021 | 2031 | 2041 | 2051 |
|---|---|---|---|---|---|
| Red blood cells | 27,926 | 31,191 | 38,985 | 38,985 | 43,199 |
| Platelets | 2,263 | 2,425 | 2,723 | 2,892 | 2,827 |
| Plasma | 1,670 | 1,796 | 1,983 | 2,152 | 2,228 |
The requirements for units of red cells (Figure 5) will increase from 27,106 in 2009 to 43,199 in 2051, with an increase of 59.4%. This increase is similar to that predicted for Italy in a study by Ali et al.1.
Figure 5.
Predicted red cell needs - central ISTAT scenario.
The platelet requirements will increase from 2,256 to 2,827 units (Figure 6) with an increase of 25.3% while plasma requirements will rise from 1,655 to 2,228 units (Figure 7), which is a 34.6% increase.
Figure 6.
Predicted platelet needs - central ISTAT scenario.
Figure 7.
Predicted plasma needs - central ISTAT scenario.
Prediction of the trend in donations
Once again, using ISTAT data and the central scenario, the trend in the population aged between 18 and 65 years could be predicted. Hypothesising that the percentage of donors remains constant (6.5% in 2009) and that the donation index (1.7) also does not change, the situation is reported in Table III.
Table III.
Predicted donations according to the central ISTAT scenario.
| 2011 | 2021 | 2031 | 2041 | 2051 | |
|---|---|---|---|---|---|
| Estimated population of 18–65 years old | 239,493 | 244,421 | 245,253 | 234,361 | 233,133 |
| Estimated donors of red blood cells | 15,637 | 15,959 | 16,013 | 15,302 | 15,222 |
| Estimated donations of red blood cells | 27,357 | 27,920 | 28,015 | 26,771 | 26,631 |
| Estimated consumption of red blood cells | 27,926 | 31,191 | 34,497 | 38,985 | 43,199 |
Table IV presents the estimated solutions to meet the increase in consumption: the donation index will have to increase to 2.8 (for the same percentage of donors in the population 18–65 years old) or the percentage of donors will have to increase to 10.6% (for the same donation index).
Table IV.
Estimated solutions to meet greater needs.
| 2011 | 2021 | 2031 | 2041 | 2051 | |
|---|---|---|---|---|---|
| Estimated number of donors needed, for the same donation index | 15,962 | 17,828 | 19,718 | 22,283 | 24,692 |
| % donors/population 18–65 years | 6.7 | 7.3 | 8.0 | 9.5 | 10.6 |
| Donation index, for the same percentage of donors | 1.8 | 2.0 | 2.2 | 2.5 | 2.8 |
Discussion and conclusions
The trend in need for red blood cells is linear, in constant increase, without showing a point of stabilisation; in contrast, the need for plasma and platelets can be described by second and third order equations, respectively, with a downward inflection indicating that the increase will not be infinite. The R2 values in all three models are very high (>0.99), which is an indicator of their high reliability.
According to the high scenario of ISTAT forecasts, the need for red blood cells will rise from 27,106 to 48,461 units in 2051, with an increase of 78.8%, platelet requirements will increase from 2,256 to 3,079 units (+36.5%) and the plasma needs will increase from 1,655 to 2,453 units (+48.2%). According to the low scenario, the red blood cell requirements will pass from 27,106 to 37,816 units in 2051, corresponding to an increase of 39.5%, platelet needs will rise from 2,256 to 2,565 units (+13.7%) and plasma requirements will increase from 1,655 to 1,995 units (+20.5%). The trends in the predictions for the other two scenario are perfectly comparable with those of the central scenario and are not, therefore, reported in detail in the figures.
The historical reference transfusion requirement indicated by the World Health Organization, that is, 40 units per 1,000 inhabitants, is an inadequate standard in our reality in which the determinant factor is the age of the population25.
Projections for the future, up to 2051, enable predictions to be made concerning expected transfusion needs, considering that the public and private hospitals in Ravenna predominantly admit inhabitants of its own territory. As seen, consumption differs greatly in the different age groups, increasing considerably with age, and this will, therefore, be the factor determining the increase in needs.
Supposing that the percentage of donors in the population between 18 and 65 years old remains constant, the number of donors is destined to decrease; therefore, in order to face the increase in needs, the donation index would need to rise from 1.7 (in 2009) to 2.8; alternatively, the percentage of donors would have to increase from 6.5% (2009) to 10.6%. These data have already been analysed, in a shorter time frame, on the basis of people already born and not, therefore, on projected demographics, without taking into account immigration26; according to this analysis donations in the province will have decreased by as much as 13% by 2026.
In the light of these predicted scenarios, it is indispensable to intervene on the appropriateness of transfusion through the Committee on Good Use of Blood: agreements were reached on protocols, promotional strategies, monitoring of consumption with 3-monthly feed-back to the individual operational units and inclusion of careful verification of consumption and guaranteeing good transfusion practices among the budget objectives. Within the Transfusion Service, the issuing of every single unit of blood is carefully considered. Nevertheless, the phenomenon of increased consumption is confirmed in the literature and therefore, besides these interventions already applied, it is important to try to increase both the proportion of donors in the population and the donation index of whole blood in order that the same recruitment criteria for donors can be maintained, thereby ensuring the safety of the donors.
Finally, it should be noted that the increased needs studied here take into account only the changing composition of the population and do not incorporate the effect of any new therapeutic uses of blood components, which cannot be predicted at present but which could become necessary in the future.
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