Indirect costs of pneumococcal diseases in Poland: estimation based on the data of the Social Insurance Institution (ZUS) regarding sickness absence
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Authors
| Name | Affiliation | |
|---|---|---|
Dominik Golicki |
Department of Experimental and Clinical Pharmacology, Medical University of Warsaw, Warsaw, Poland
|
|
Katarzyna Jaśkowiak |
HealthQuest Sp. z o.o, Warsaw, Poland |
|
Iwona Dobrowolska |
HealthQuest Sp. z o.o, Warsaw, Poland |
|
Maciej Niewada |
Department of Experimental and Clinical Pharmacology, Medical University of Warsaw, Warsaw, Poland
|
Background: The study aimed to estimate the indirect
costs of pneumococcal diseases in Poland based on the data of the Social
Insurance Institution (ZUS) regarding sickness absence.
Methods: The study included the following diseases,
which may be caused by Streptococcus
pneumoniae: meningitis, sepsis, pneumonia and otitis media (OM). Indirect
costs resulting from adults’ sick leave for their own sickness or for caring
for a sick child were taken into account. The ZUS data concerning all diagnoses
of the analysed diseases, regardless of the aetiology, was used. The data was
corrected for the share of cases caused by S.
pneumoniae, determined based on epidemiological data found in the
literature. Epidemiological data were searched in the following databases:
MEDLINE, Polska Bibliografia Lekarska and on the NIZP-PZH website. The unit cost
of lost productivity was estimated based on the methodology recommended by
AOTMiT HTA guidelines (2016), including methods suggested in the EY (2013) and
INFARMA (2014) reports.
Results: Total absenteeism due to pneumococcal
diseases amounted to approx. 302,000 days, of which 156,000 days were absences
due to own illness and 146,000 days because of child care. The total indirect
costs of absenteeism due to diseases caused by S. pneumoniae amounted to approx. PLN 95.5 million, of which PLN
49.4 million were the costs of diseases in the adult population (including 90%
of pneumococcal pneumonia), and 46.1 PLN million costs resulting from
children's diseases (in 57% and 42%, respectively, costs of OM and pneumonia).
Conclusions: Diseases with pneumococcal aetiology are
the cause of a significant number of sickness absence and indirect costs
arising from them are at a level similar to the costs of purchasing vaccines
for the universal pneumococcal vaccination program.
Introduction
Pneumococcal infection is caused by Streptococcus pneumoniae, known
colloquially as pneumococci. Pneumococci are the most common cause of
community-acquired bacterial respiratory infections such as otitis media (OM),
sinusitis, exacerbation of chronic bronchitis and pneumonia. The most severe
form of pneumococcal infection is the so-called invasive pneumococcal disease (IPD).
This concept includes meningitis, sepsis and pneumonia with bacteraemia.[1]
Pneumococcal infection is one of the leading causes of
morbidity and mortality in the world.[2] According to WHO estimates
based on data from 2000 (before the introduction of Prevenar® vaccine),
S. pneumoniae was responsible for
14.5 million cases of severe infections and 735,000 deaths annually among
children up to 5 years of age worldwide. According to more recent WHO
estimates, in 2008, S. pneumoniae
infections caused about 476,000 deaths among children up to 5 years of age not
infected with HIV, which constitutes 5% of deaths among children in this age
group.[3] In 2017 in Poland, the National Institute of Public Health
(NIZP) and the Main Sanitary Inspectorate (GIS) recorded 1,877 IPD cases,
including 171 cases of meningitis and 809 cases of sepsis.[4]
According to the traditional division of costs in
pharmacoeconomics, we distinguish the following cost categories: direct
(medical and non-medical), indirect and intangible costs.[5] The
category of indirect costs is associated with reduced productivity of patients
in working age. In many diseases, the indirect costs are higher than the direct
medical costs.[6]
Pneumococcal diseases are not only a significant
clinical problem but also have significant social and financial consequences.
In Poland, the economic consequences of pneumococcal diseases are relatively
poorly studied. In particular, there are no publications on indirect costs. The
analysis aimed to estimate the indirect costs of pneumococcal diseases in
Poland based on the data of the Social Insurance Institution (ZUS) regarding absenteeism.
Material and methods
The study included the following diseases, which may
be caused by S. pneumoniae: sepsis, meningitis,
pneumonia and otitis media (OM).
The following categories of indirect costs were taken
into account: sickness absenteeism due to own disease and absence resulting
from taking care of sick children. The indirect costs of informal care, disease
complications or premature death were not included. In the estimation of
indirect costs due to an adult's disease, sickness absence due to otitis media
was not considered due to the absence of an indication of Prevenar 13®
vaccine for the prevention of OM in this population.[7]
Methods for estimating absenteeism
Indirect costs were estimated based on ZUS data on abseenteism. Publicly available data on adult sickness absence from their own diseases from 2012 - 2017 were analysed (Figure 1).[8] Data on sick leave for the care of a sick child was obtained from ZUS in the mode of access to public information.[9] Due to their time limit up to a single year, it was decided that in the case of both categories of absences, the data from the last available year (2017) will be used in the estimation of indirect costs.
The information provided by the ZUS made it possible to analyse the causes of sick leave defined by the ICD-10 classification (three-character categories). Among the analysed diseases, bacterial meningitis and sepsis are a direct threat to the patient's life. Therefore, it is recommended to determine the etiological factor and its susceptibility to antibiotics and to notify the Poviat or Provincial Sanitary Inspector. Nevertheless, in some cases, it is difficult to obtain a positive and reliable result of the bacteriological examination.[10] In the case of community-acquired pneumonia and otitis media, the diagnosis is primarily based on symptoms. In an outpatient setting, a microbiological diagnosis of infection is rarely performed.[11] Given the above, ICD-10 diagnoses indicated by physicians issuing sick leave may not fully reflect the actual, detailed aetiology of the analysed diseases. It was decided that in the estimation of indirect costs of absenteeism, sick leaves with all diagnoses of the analysed diseases will be included, regardless of their aetiology (Table 1), while the total number of sick leave days for the analysed diseases will be adjusted by the percentage of cases caused by S. pneumoniae, determined based on epidemiological data found in the published literature.
Table 1. Included diseases with corresponding ICD-10 codes.
Disease | ICD-10 codes |
| Pneumonia | J12 Viral pneumonia, not elsewhere classified J13 Pneumonia due to Streptococcus pneumoniae J14 Pneumonia due to Haemophilus influenzae J15 Bacterial pneumonia, not elsewhere classified J16 Pneumonia due to other infectious organisms, not elsewhere
classified J17 Pneumonia in diseases classified elsewhere |
| Otitis media | H65 Nonsuppurative otitis media H66 Suppurative and unspecified otitis media |
| Meningitis or encephalitis | G00 Bacterial meningitis, not elsewhere classified G02 Meningitis
in other infectious and parasitic diseases classified elsewhere G03 Meningitis due to other and unspecified causes G04 Encephalitis, myelitis and encephalomyelitis |
| Sepsis | A40 Streptococcal sepsis |
According to the information provided by ZUS, in 80.8%
of sick leaves for child care issued in 2017, there is no ICD-10 code of the
disease entity.[9] It was assumed that the missing diagnoses are
distributed in a manner proportional to the share of diagnoses reported and the
number of absenteeism days due to care for a sick child in ZUS data was
corrected by the index of 0.192.
Epidemiology of infections with the pneumococcal aetiology
In order to identify epidemiological data on the
percentage of pneumonia, OM, meningitis and sepsis of pneumococcal aetiology in
Poland, the following databases were searched: Polska Bibliografia Medyczna (PBL;
since 1991), data from the National Institute of Public Health - National
Institute of Hygiene (NIZP-PZH) regarding epidemiology of infections in Poland
and hospital sickness as well as the MEDLINE base (PubMed). Because universal
vaccination of children against pneumococcus was introduced in Poland from
January 2017 and population effects have not yet fully developed,
epidemiological data was sought regarding the period preceding the introduction
of universal vaccination against pneumococci in a given region.
No specific Polish epidemiological data were found to
estimate the proportion of pneumococcal aetiology in the total number of cases
of pneumonia and OM infections in the pediatric population. The aforementioned
involvement of the aetiology of S. pneumoniae
was estimated based on published worldwide literature: 22.0% and 17.3% for
pneumococcal pneumonia in children and adults, respectively - based on a study
on the burden of pneumococcal disease in Canada[12] and a
meta-analysis of observational studies;[13] 30.2% for pneumococcal OM
in children - based on a systematic review.[14] The percentage of meningitis
and sepsis cases with pneumococcal aetiology was estimated based on specific
Polish data (NIZP-PZH, 2017) at 19.0% in both children and adults populations.[15]
Methods for estimating indirect costs
Indirect costs were estimated in accordance with the
current HTA guidelines of the Agencja Oceny Technologii Medycznych i
Taryfikacji (AOTMiT, 2016),[16] taking into account the methodology
described in the reports "Methodology for measuring indirect costs in the
Polish healthcare system" (EY, 2013)[17] and "Indirect
costs in the health technology assessment. Methodology, pilot study and
recommendations "(INFARMA, 2014).[6]
The estimation of unit costs of lost productivity (Table 2) is based on the latest, complete data of the Central Statistical Office of 2016, concerning the gross domestic product (GDP) and the number of employees.[18] In the first step, the value of GDP per employee was estimated. In the second, a correction factor was applied for marginal productivity - at the level of 0.65, adopted among others, by the European Commission.[17] It was assumed that the year consists of 250 working days. The adjusted cost of lost productivity for one day of work absence was estimated at PLN 315.99 (Table 2). Lost productivity due to absenteeism was estimated as the ratio of the number of days of sick leave and unit cost of lost productivity.
Table 2. Estimation of the unit cost of lost
productivity.
| Parameter | Value | Reference |
| Gross Domestic Product (GDP) [PLN million] | 1,858,637 | GUS 2018 [18] |
| Number of employee [thousand] | 15,293.3 | GUS 2018 [18] |
| GDP/employee [PLN] | 121,532.76 | Own estimation |
| Correction factor for decreasing, marginal work
productivity | 0.65 | EY 2013 [17] |
| GDP/employee adjusted by decreasing, marginal
productivity of work [PLN] | 78,996.30 | Own estimation |
| The number of working days in a year | 250 | Assumption |
| The unit cost of lost productivity [PLN/day of
absence] | 315.99 | Own estimation |
Results
The number of days of absenteeism
The analysis of the ZUS data on sickness absence due
to own illness from 2012 - 2017 showed that among diseases with potentially
pneumococcal aetiology, the highest sickness absence was due to pneumonia
(ICD-10 J12-J18) - from approx. 723,000 up to 935,000 days of absence, in 2014
and 2013, respectively (Fig. 1). In the case of meningitis (ICD-10 G00,
G02-G05), the number of absence days at work ranged from about 41,000 in 2012
to around 49,000 in 2016, and in the case of sepsis (A40, A41) at the level of
about 28,000 days in 2013 to approx. 38,000 in 2017-2018. According to ZUS
data, the average length of one sick leave for own illness was the highest in the
case of sepsis (mean 25.1 days) and meningitis (21.5 days). In the case of
pneumonia, it was at a lower level - an average of 9.4 days.[8]
Indirect costs were estimated based on ZUS data from 2017 (the only available data on absences because of childcare with ICD-10 codes; the last available ZUS data on absences from own sickness). In 2017, sickness absence among adults, caused by S. pneumoniae infections, was estimated at 156,200 of which the majority (89.8%) were caused by absence due to pneumococcal pneumonia, with pneumococcal meningitis and sepsis accounting for 5.5% and 4.7% of the number of days of absence, respectively (Table 3). In the same year, the number of days of sick leave due to child care, resulting from pneumococcal aetiology diseases, amounted to about 146,000. The pneumococcal OM and pneumonia were responsible for the most significant number of days of absence - 56.6% and 41.9%, respectively. Absenteeism of caregivers due to pneumococcal diseases of children with the severe course - meningitis and sepsis accounted for 0.8% and 0.6% of the number of absence days, respectively (Table 3, Table 4).
Table 3. Number of sick leave days due to S. pneumoniae infection for own sickness in 2017 and estimated indirect costs.
| The reason for the sick leave (ICD-10 code) | The number of sick days without regard to
etiology[8, 9] | Percentage of cases of pneumococcal etiology | The number of days of sick leave due to S. pneumoniae | The indirect cost of sick leave due to S.
pneumoniae infections* [PLN] |
| Pneumonia (J12-J18) | 810,888 | 17.3% [13] | 140,284 | 44,327,547 |
| Meningitis or encephalitis (G00, G02-G05) | 45,499 | 19% [15] | 8,636 | 2,728,756 |
| Sepsis (A40, A41) | 38,325 | 19% [15] | 7,274 | 2,298,503 |
| Total | 894,712 | n.a. | 156,193 | 49,354,806 |
* Assuming
the unit cost of lost productivity at the level of PLN 315.99; n.a. – not
adequate.
Table 4. Number of sick leave days due to S. pneumoniae infection for sick child care in 2017 and estimated indirect costs.
| The reason for the sick leave (ICD-10 code) | The number of sick days without regard to etiology[8, 9] Raw data | The number of sick days without regard to etiology[8, 9] Adjusted data* | Percentage of cases of pneumococcal etiology | The number of days of sick leave due to S. pneumoniae | The indirect cost of sick leave due to S.
pneumoniae infections** [PLN] |
| Pneumonia (J12-J18) | 53,410 | 278,177 | 22% [12] | 61,199 | 19,337,964 |
| Otitis media (H65-H67) | 52,586 | 273,885 | 30.2% [14] | 82,713 | 26,136,208 |
| Meningitis or encephalitis (G00, G02-G05) | 1,214 | 6,323 | 19% [15] | 1,200 | 379,211 |
| Sepsis (A40, A41) | 916 | 4,771 | 19% [15] | 906 | 286,126 |
| Total | 108,126 | 563,156 | n.a. | 146,018 | 46,139,508 |
* The percentage of sick leaves without the given diagnosis was taken into account (80.8%; correction factor 0.192); ** Assuming the unit cost of lost productivity at the level of PLN 315.99; n.a. – not adequate.
Indirect costs
The indirect costs of absenteeism due to diseases
caused by S. pneumoniae in the adult
population in 2017 were estimated at approximately PLN 49.4 million (Table 3).
These included indirect costs due to: pneumococcal pneumonia - approx. PLN 44.3
million, meningitis - approx. PLN 2.7 million and sepsis - approx. 2.3 million.
The indirect costs of absenteeism due to child care
caused by S. pneumoniae infections
were at a similar level as indirect costs due to own illness and amounted to
approx. PLN 46.1 million. These included mainly the indirect costs of
pneumococcal OM and pneumonia - 26.1 and 19.3 million, respectively, and, to a
much lesser extent, the costs of pneumococcal meningitis and sepsis – PLN 0.4
and 0.3 million, respectively.
In total, in 2017, as a result of S. pneumoniae infections, about 302,200 sick leave days, of which approx. 48.3% related to absence due to the care of a sick child. The indirect costs of absence from work caused by S. pneumoniae infections can be estimated at a total of approx. PLN 95.5 million (Figure 2).
Figure 2. List of indirect costs of sick leave due to S. pneumoniae infection (A) for own illness* and (B) for childcare** in 2017 (Source: own estimations based on ZUS data and published literature review).
* the number of days of sick absence was estimated
based on the percentages of pneumococcal etiology: pneumonia - 22.0%, meningitis
or encephalitis, sepsis - 19.0%; ** estimated using the following percentages
of pneumococcal etiology: pneumonia 22.0%, otitis media - 30.2%, meningitis or
encephalitis, sepsis - 19.0%.
Discussion
In the present study, we estimated the indirect costs
of absenteeism caused by pneumococcal pneumonia, meningitis and sepsis in 2017
in Poland. We based our calculations on the ZUS data on the number of days of
sickness absence due to own disease or care for a sick child, epidemiological
data on the participation of S.
pneumoniae in the aetiology of the diseases mentioned above and estimation
of the unit cost of lost productivity in accordance with the AOTMiT guidelines.
In our analysis, we focused on indirect costs of
sickness absence in professionally active people, omitting several other
categories of indirect costs, such as costs of informal care, premature death
or presenteeism.[5] Due to the difficulties with the clear
identification of primary data, we did not take into account the indirect costs
of long-term complications resulting from severe pneumococcal diseases (e.g.
deafness or disability after pneumococcal meningitis). In connection with the
above, the total, real indirect costs of pneumococcal diseases will be higher
than estimated in this analysis.
Even though ZUS data on sick leave have
three-character ICD-10 codes, they are not a reliable source of information on
the detailed aetiology of infection (S.
pneumoniae or other pathogenic microbe). Certain diseases - e.g.
community-acquired pneumonia or otitis media - are usually treated without a
microbiological examination. Even in the case of serious diseases - meningitis
- where cultures are performed routinely, the proportion of cases with
undetermined bacterial or other aetiology can reach 74% (data from NIPP-PZH,
2015).[15] For this reason, it was decided that ZUS data will be a
source of general information about the disease (pneumonia, OM, meningitis,
sepsis), while the participation of S.
pneumoniae aetiology will be estimated based on available data from the
review of epidemiological studies. Regarding non-hospital pneumonia in adults
and children and the OM in children, we did not find Polish epidemiological
data, and the percentage of infections caused by S. pneumoniae was based on observational data from other countries.
In turn, in relation to meningitis and sepsis, due to the lack of data divided
into children and adults, it was assumed that in both populations, the
percentage of pneumococcal aetiology would be the same.
An essential limitation of the ZUS data on sick leave
due to childcare is the lack of information on the diagnosis of the disease
(ICD-10 code) at the level of 80.8% of all records.[9] It can be
assumed that in the case of severe diseases associated with hospitalisation
(sepsis or meningitis) the percentage of diagnosis reporting is greater, but
due to the lack of data, it is impossible to estimate. An assumption was made
about the proportionality of missing data to available data (equal
participation of a given disease in all diagnoses), and adjustment of raw ZUS
data was carried out.
To our knowledge, the current study is the first
published estimate of indirect costs of pneumococcal diseases in Poland. In
general, the literature on this topic is not numerous, although research has
been found from Denmark, Switzerland, Turkey or the United States.[19,20,21,22]
The US authors indicate that vaccinations against pneumococcus allow savings in
indirect costs exceeding 70% savings in direct costs.[22] According
to the Turkish researchers, indirect costs account for 21%, 26% and 84% of of
pneumococcal meningitis, pneumonia and OM total costs, respectively.[21]
The Danish authors indicate that the failure to take indirect costs into
account in the economic analysis of pneumococcal vaccination leads to undervaluation
of pneumococcal vaccination.[19]
Considering the practical implications of our
analysis, it should be noted that the estimated total value of indirect costs
of absenteeism due to pneumococcal diseases of professionally active people is
at a level similar to the expenditure of the Ministry of Health for
pneumococcal vaccines under the universal vaccination program (PSO).
Considering that we omitted several indirect costs categories in the estimation
and we did not refer to direct medical costs at all, the introduction of
universal vaccinations against pneumococcus seems to involve a high budget
saving potential, balancing the direct expenditure on the purchase of vaccines.
Future studies on indirect costs of pneumococcal
diseases in Poland should focus on determining the costs associated with
premature deaths, informal care and presentism. It is also crucial to determine
the indirect costs of long-term complications of severe pneumococcal diseases -
e.g. deafness or disability after meningitis, which will require good quality
data from real clinical practice (real world data, RWD). Finally, studies using
quality of life questionnaires can broaden our knowledge about the intangible costs
of pneumococcal diseases.
Conclusions
Diseases with pneumococcal aetiology are the cause of
a significant number of sickness absence and indirect costs arising from them
at a level similar to the costs of vaccines for the universal pneumococcal
vaccination program. In adults, the primary source of indirect costs is
pneumonia, in children - otitis media together with pneumonia.
Conflict of interests
The study was supported by Pfizer Polska Sp. z o.o.
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