Prevalence of multiple sclerosis in Poland - Multiple Sclerosis and ...

Multiple Sclerosis and Related Disorders 21 (2018) 51–55

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Prevalence of multiple sclerosis in Poland a,⁎

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b

b

a

Katarzyna Kapica-Topczewska , Waldemar Brola , Malgorzata Fudala , Joanna Tarasiuk , Monika Chorazya, Katarzyna Snarskac, Jan Kochanowicza, Alina Kulakowskaa a b c

Department of Neurology, Medical University of Bialystok, Bialystok, Poland Department of Neurology, Specialist Hospital, Konskie, Poland Department of Clinical Medicine, Medical University of Bialystok, Bialystok, Poland

A R T I C L E I N F O

A B S T R A C T

Keywords: Multiple sclerosis Prevalence Poland

Objective: The prevalence of multiple sclerosis (MS)was previously unknown in Poland. The aim of this study was to determine the prevalence of MS in Poland. Methods: MS prevalence was determined on the basis of data from the Swietokrzyskie (central Poland) and Podlaskie (northeastern Poland) Voivodeships. The area population on the prevalence study day (December 31, 2013) was 1,268,239 (649,007 women; 619,232 men) in central and 1,195,625 (612,979 women; 582,646 men) in northeastern Poland. Results: The overall crude prevalence rate of confirmed MS patients was 109.1/100,000 (95% confidence interval[CI]103.5–115.0) in the Swietokrzyskie and 108.7/100,000 (95% CI 103.0–114.7) in the Podlaskie Voivodeships. A significantly higher prevalence was recorded in females (149.8/100,000, 95% CI 140.6–159.3 vs. 142.4/100,000, 95% CI 133.3–152.0) than in males (66.5/100,000, 95% CI 60.4–73.1 vs.57.8/100,000, 95% CI 52.0–64.2)(p < 0.001). Age-adjusted rates for the Polish Standard Population were the same in both regions (110.3/100,000 (95% CI 104.6–116.1) vs.110.9/100,000 (95% CI 105.1–117.1)) and for the European Standard Population did not different statistically between both voivodeships (103.9/100,000 (95% CI 98.6–109.5) vs.108.5/100,000 (95% CI 102.7–114.5)). Conclusion: This is the first data that obtained the level of MS prevalence in Poland and confirmed that Poland is a high-risk area for multiple sclerosis.

1. Introduction Multiple sclerosis (MS) is a chronic inflammatory demyelinating disease of the central nervous system that leads to oligodendrocyte degeneration and the destruction of neurons and axons. The estimated number of people with MS in the world is approximately 2.3 million (Atlas of MS, 2013, 2013; Lad et al., 2010). In Poland, the number of patients with MS was previously unknown, as there have not been systematic long-term epidemiological studies of the entire population. For several decades, no registry of patients with MS existed. The systematic collection of epidemiological data was initiated in 2010. With the goal of long-term observation of patients with MS, a team of IT specialists from the AGH University of Science and Technology in Krakow designed a computer programme that became the basis for a registry of patients with MS (RejSM) (Brola et al., 2016). The first registration of patients began in the Swietokrzyskie Voivodeship (central Poland) and then the Podlaskie Voivodeship (northeastern Poland). Since 2013, the RejSM has been an all-Poland project.

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However, the only regions where data were collected were the Swietokrzyskie and Podlaskie Voivodeships. This work presents the results and is an attempt to identify MS prevalence in Poland. 2. Methods The aim of this population-based study was to determine the prevalence of MS in Poland in 2013 based on data from the Swietokrzyskie (central Poland) and Podlaskie (northeastern Poland) Voivodeships. With a population of over 38.5 million people, Poland is the 8th most populous country in Europe and the 6th most populous member of the European Union. The country is ethnically and culturally homogenous. In Poland, after World War II, the migration of people from eastern to western regions resulted in the mixing of traditions, including food habits. Moreover, there is no climate difference in Poland, because it has a relatively small latitudinal extent. Additionally, Poland has the smallest number of foreign citizens in United Europe (< 0.1%, according to Eurostat). It is a unitary state divided into 16 administrative

Correspondence to: Medical University of Bialystok, Department of Neurology, ul. Sklodowskiej 24 A, 15-276 Bialystok, Poland. E-mail address: [email protected] (K. Kapica-Topczewska).

https://doi.org/10.1016/j.msard.2018.02.016 Received 6 September 2017; Received in revised form 25 January 2018; Accepted 10 February 2018 2211-0348/ © 2018 Elsevier B.V. All rights reserved.


K. Kapica-Topczewska et al.

patients with MS living in the northeastern region. Informed consent was obtained from each participant, or the next of kin, before any interview or neurological examination was conducted. All individual data were automatically anonymised by replacement of personal identity numbers (PESEL) with unique number codes for use in the study. The study was approved by the Regional Medical Ethics Committee (the Swietokrzyskie Medical Council in Kielce and the Medical University of Bialystok). 2.1. Statistical analysis Prevalence was based on the number of MS patients registered in the RejSM who were residents of the Swietokrzyskie region on the prevalence study date of December 31, 2013. In northeastern Poland, prevalence was based on the number of MS patients registered in the local National Health Fund data-base (which included all patients presenting to health-care facilities with ICD 10 G35 in 2013). Prevalence was expressed as the number of all cases on the prevalence study day divided by the population of the Swietokrzyskie Voivodeship on the same day (available in the Demographic Yearbook of Poland 2014) (Size and structure of population, 2014). Crude sex and age areaspecific prevalences were calculated as the number of cases on the prevalence study day per 100,000 inhabitants. MS prevalence was adjusted by a direct method, using the Polish and European population as a standard. The 95% confidence intervals (CIs) for age-adjusted prevalence were calculated using Fay-Feuer methodology (Fay and Feuer, 1997), while the significance of differences in age-adjusted prevalence between voivodeships were computed using the Poisson Generalised Linear Model. Comparisons of continuous variables (time-interval from onset of the first symptoms to diagnosis and EDSS (Expanded Disability Status Scale)) were compared between Podlaskie and Swietokrzyskie Voivodships using the Student's t-test, due to the availability of aggregated data from Swietokrzyskie Voivodship only. P-values of < 0.05 were considered statistically significant. Statistical analysis was performed using IBM SPSS Statistics version 20.0.

Fig. 1. Map of Poland showing the locations of the Swietokrzyskie and Podlaskie Voivodeships.

voivodeships (Fig. 1). The area population on the prevalence study day (December 31, 2013) was 1,268,239 (649,007 women and 619,232 men) in the Swietokrzyskie Voivodeship and 1,195,625 in the Podlaskie Voivodeship (612,979 women and 582,646 men) (Size and structure of population, 2014). This study was performed at the MS Centre of the Department of Neurology of the Specialist Hospital in Końskie, and 7 main hospital centres in the Swietokrzyskie Voivodeship. In the Podlaskie Voivodeship, data were collected from patients treated at the Department of Neurology and Outpatient Clinic of the Medical University of Bialystok (it was the only MS treatment centre in this region). The study included only patients over 18 years of age. The web-based version of the RejSM (http://www.rejsm.pl) was started in 2010. Patients with MS, according to the 2005 McDonald criteria, were registered and followed up at each visit. PESEL (Powszechny Elektroniczny System Ewidencji Ludności; Universal Electronic System for the Registration of the Population) numbers (11digit unique identity numbers mandatory in Poland since 1979) were relevant to the study because they ensured that MS patients registered only once in the survey. The data were recorded by an experienced neurologist. All patients with a definite diagnosis of MS who were born and lived in the Swietokrzyskie Voivodeship were recruited into the study on the prevalence study day (December 31, 2013). A total of 1384 MS patients were considered in the prevalence estimation, which is comparable with National Health Fund data. In the Podlaskie Voivodeship, the study involved 815 patients with MS. Data were collected from patients treated at the Department of Neurology, Medical University of Bialystok, and Outpatient Clinic, on the basis of standardised medical histories. Neurological examination was performed by a neurologist. Furthermore, information from the patients was compared with National Health Fund data, which included all patients presenting to healthcare facilities with ICD 10 (10th revision of the International Statistical Classification of Diseases and Related Health Problems) G35 in 2013 (1299 patients with MS). Comparison of the collected data (sex, age, number in each age group) with National Health Fund data indicated that the survey is a representative sample of approximately 62% of the population of MS patients in the Podlaskie Voivodeship. In addition, these data were recorded in the Polish Multiple Sclerosis Registry (RejSM). The prevalence rate was measured using National Health Fund data because those data were comparable with the collected data and included all

3. Results 3.1. Central Poland (Swietokrzyskie Voivodeship) On the prevalence study day (December 31, 2013), 1384 subjects (412 men and 972 women) were identified. The overall crude prevalence in the Swietokrzyskie Voivodeship population of 1,268,239 was 109.1/100,000 (95% CI 103.5–115.0). A significantly higher prevalence rate was recorded in females (149.8/100,000; 95% CI 140.6–159.3) than in males (66.5/100,000; 95% CI 60.4–73.1) (p < 0.001) (Table 1). The age-adjusted prevalence rate standardised to the Polish population was 110.3/100,000 (95% CI 104.6–116.1), and the age-adjusted prevalence rate standardised to the European standard population was 103.9/100,000 (95% CI 98.6–109.5) (Table 2). 3.2. Northeastern Poland (Podlaskie Voivodeship) On the prevalence study day (December 31, 2013), 1299 subjects (427 men and 872 women) were identified. The overall crude prevalence in the Podlaskie Voivodeship population of 1,195,625 was 108.7/100,000 (103.0–114.7). A significantly higher prevalence rate was recorded in females (142.4/100,000; 95% CI 133.3–152.0) than in males (57.8/100,000; 95% CI 52.0–64.2) (p < 0.001). The age-adjusted prevalence rate standardised to the Polish population was 110.9/ 100,000 (95% CI 105.1–117.1), and the age-adjusted prevalence rate standardised to the European population was 108.5/100,000 (95% CI 102.7–114.5) (Table 3). Age-adjusted rates for the Polish Standard Population were the same in both regions, and did not different statistically between both 52



Table 1 Age-and sex-specific MS prevalence per 100,000 inhabitants in the SwietokrzyskieVoivodeship on December 31, 2013a. Male

Female

Total

Age -years

Cases

Popula tion

Preva lence

95% Cl

Cases

Popula tion

Preva lence

95% Cl

Cases

Popula tion

Preva lence

95% Cl

< 15 15–24 25–34 35–44 45–54 55–64 > =65 Total

0 18 113 134 82 48 17 412

91,140 82,154 102,406 90,837 82,399 91,499 78,797 619,232

– 21.9 110.3 147.5 99.5 52.5 21.6 66.5

– 13.92–33.13 91.83–131.60 124.61–173.5 80.23–122.18 39,62–68.31 13.54–32.97 60.4–73.1

0 36 248 285 252 132 19 972

86,334 78,156 95,310 85,191 81,289 97,498 125,229 649,007

– 46.1 260.2 334.5 310.0 135.4 15.2 149.8

– 33.33–62.28 229.81–293.57 297.93–374.48 274.06–349.43 114.22–159.44 9.76–22.72 140.6–159.3

0 54 361 419 334 180 36 1384

177,474 160,310 197,716 176,028 163,688 188,997 204,026 1,268,239

– 33.7 182.6 238.1 204.1 95.2 17.6 109.1

– 25.85–43.24 164.71–201.89 216.32–261.36 183.33–226.50 82.32–109.65 12.77–23.86 103.5–115.0

Cl-confidence interval. a Based on data provided by the Polish Central Statistical Office.

2004). Similar prevalence was obtained in the Szczecin Voivodeship in 2008 (91.8/100,000) (Potemkowski, 2009) and in the city of Kielce in 2012 (98.53/100,000) (Potemkowski and Jasińska, 2015). This increase is due to the existence of new diagnostic criteria for MS and greater availability of MRI machines. Taking into account the results obtained in this study and the results mentioned above, it can be assumed that the rate of prevalence of MS in Poland is approximately 110/100,000 residents. A similar or slightly higher prevalence of MS was also found in the neighbouring countries of Germany and the Czech Republic (Haupts et al., 1994; Vachova, 2012; Poser, 1994), while in the Nordic countries, a higher prevalence has been reported (Ahlgren et al., 2011; Bentzen et al., 2010; Grytten et al., 2016; Bostrom et al., 2009; Svenningsson et al., 1990). In Sweden and Norway, the highest rates of MS prevalence and incidence in the world have been found, which in long-term studies showed an upward trend. As in Poland, the growth of these indicators could result from faster early diagnosis, using the current criteria for diagnosis, and improving the quality of health-care (Ahlgren et al., 2011; Grytten et al., 2016; Svenningsson et al., 1990). There is a theory that MS originally appeared in south-central Sweden, spread to its neighbours and, in the 17th century, spread southward to the continent, and later to all of Europe and other continents (Kurtzke, 2013, 2015). Interestingly, an increase in MS prevalence was also recorded in the Middle East, which in turn can be associated with the prevalence of the,western lifestyle” in the region and with frequent smoking, more pollution, using skin preparations protecting against ultraviolet radiation, and clothing styles that cover most of the body resulting in lower levels of vitamin D (Kurtzke, 2015; Heydarpour et al., 2015). The time interval from the onset of first symptoms to diagnosis was 2.4 ± 4.68 years in central Poland and 3.7 ± 5.3 years in northeastern Poland. The relatively long time from symptom onset to diagnosis in northeastern Poland may stem from the fact that this is a region with the lowest population density in Poland (59 inhabitants/km2 vs. the average 123 inhabitants/km2 for the whole country), and 44.1% of people live in villages and small towns (less than 5000 inhabitants) (Area and population in the territorial profile, 2013). Thus, patients in

voivodeships for the European Standard Population (Table 2). We can conclude that those regions are a representative sample of the entire population of MS patients in Poland. Taking into account the results obtained in this study, it can be assumed that the rate of multiple sclerosis prevalence in Poland is approximately 110/100,000 residents. The enrolled patients showed a similar clinical course of the disease in central Poland (relapsing-remitting − 68.5%, primary-progressive − 6.4%, secondary-progressive − 22.5% and progressive-relapsing − 2.9%) and northeastern Poland (relapsing-remitting − 69.3%, primary-progressive − 6.2%, secondary-progressive − 24.5%). The mean EDSS score was comparable in both regions (in central Poland mean EDSS was 3.4 ± 2.18; for females: 3.6 ± 2.2; for males: 3.2 ± 2.3; in northeastern Poland, mean EDSS was 3.33 ± 2.15; for females: 3.2. ± 2.1; for males: 3.5 ± 2.3) (Table 4). It is interesting that we found a significant difference between the time interval from the onset of first symptoms to diagnosis for the two voivodeships (in central Poland 2.4 ± 4.68 and in northeastern Poland 3.7 ± 5.3 (4.1 ± 5.7 in women and 2.8 ± 4.0 in men)) (Table 4). 4. Discussion In Poland, no epidemiological studies of the entire population have been conducted, and MS prevalence in various regional studies varied significantly, ranging from 37 to 91/100,000 residents (Cendrowski, 1965; Cendrowski et al., 1969; Wender et al., 1985; Potemkowski, 1999, 2001; Fryze and Obiedziński, 1996; Łobińska and Stelmasiak, 2004). Most of these studies were conducted several years ago, when MS was diagnosed using Schumacher or Poser criteria, which did not allow for early diagnosis (Schumacher et al., 1965; Poser et al., 1983). In the first epidemiological studies of Cendrowski et al., the MS prevalence rate in 1954 was 37/100,000 in Krosno and 43/100,000 in Bydgoszcz (Cendrowski, 1965; Cendrowski et al., 1969). Wender et al. obtained similar results in 1981 in Great Poland (western part of the country) (Wender et al., 1985). Long-term studies demonstrated an increase in prevalence over the years: for example, the multiple sclerosis prevalence rate in Gniezno was 53.4/100,000 in 1965 and 97.8/100,000 in 1999 (Wender et al., 1985, 1987; Kaźmierski et al.,

Table 2 MS prevalence per 100,000 inhabitants in the Swietokrzyskie and Podlaskie Voivodeships on December 31, 2013. SEX

M F Total

Central Poland - SwietokrzyskieVoivodeship

Northeastern Poland - Podlaskie Voivodeship

Prevalence

Preva lence

66.5 149.8 109.1

95%Cl

60.4–73.1 140.6–159.3 103.5–115.0

Standard Population Poland

95%Cl

European

95%CL

66.5 152.9 110.3

60.4–73.1 143.6–162 104.6–116.1

61.7 147.9 103.9

55.9–67.8 138.8–157.4 98.6–109.5

57.8 142.4 108.7

Cl-confidence interval.

53

95%Cl

52.0–64.2 133.3–152.0 103.0–114.7

p*

Standard Population Poland

95% Cl

European

95% CL

60.0 145.6 110.9

53.9–66,6 136.3–155.4 105.1–117.1

57.4 142.2 108.5

51.5–63 133.0–151.8 102.7–114.5

0.057 0.280 0.920



Table 3 Age-and sex-specific MS prevalence per 100,000 inhabitants in the Podlaskie Voivodeship on December 31, 2013a. Male

Female

Total

Age -years

Cases

Popula tion

Preva lence

95% Cl

Cases

Popula tion

Preva lence

95% Cl

Cases

Population

Preva lence

95% Cl

< 18 18–24 25–34 35–44 45–64 55–64 65–74 75–84 > 85 Total

2 16 57 73 106 132 29 11 1 427

109,777 6,0566 99,585 84,327 82,001 75,991 38,520 25,146 6733 582,646

1.82 26.42 57.24 86.57 129.2 173.70 75.29 43.74 14.85 57.8

0.56–5.08 16.35–40.85 44.23–73.02 68.91–107.52 102.08–160.17 146.54–204.56 52.55–105.06 24.66–73.13 3.60–54.79 52.0–64.2

1 20 95 122 263 255 78 29 9 872

104,233 57,529 92,693 81,370 81,378 82,123 52,272 44,113 16,608 612,979

0.96 34.77 102.49 149.93 323.18 310.51 149.2 65.74 54.19 142.4

0.23–3.54 22.60–51.58 83.89–124.10 125.63–177.68 286.46–363.39 274.71–349.76 119.65–184.11 45.88–91.74 28.87–94.91 133.3–152.0

3 36 152 195 369 387 107 40 10 1299

214,010 118,095 192,278 165,697 163,379 158,114 90,792 69,259 23,341 1,195,625

1.40 30.48 79.05 117.68 225.86 244.76 117.85 57.75 42.84 108.7

0.51–3.38 22.06–41.22 67.46–92.10 102.31–134.77 203.98–249.47 221.58–269.74 97.58–141.21 42.48–76.98 23.53–73,20 103.0–114.7

Cl-confidence interval. a Based on data provided by the Polish Central Statistical Office.

Jasińska, 2015; Kulakowska et al., 2010; Pierzchala et al., 2015). We are aware that our study also has some limitations. First, it is based on analysing all patients with MS living in two different regions. Nevertheless, these regions are a representative sample of the entire population of MS patients living in Poland. Otherwise, we realise that the oldest and most disabled patients may not have been identified. Additionally, some young patients suffering from mild forms of multiple sclerosis could have avoided or not required any contact with healthcare services. However, systematic implementation of the registry over the next several years should allow us to identify the entire population of MS patients, not only from the Swietokrzyskie and Podlaskie Voivodeships, but from other regions or the entire country as well.

Table 4 Time interval from the first symptom onset to diagnosis and EDSS in the Swietokrzyskie and Podlaskie Voivodeships.

Time interval from the first symptom onset to diagnosis (years) Mean EDSS

Swietokrzyskie Voivodeship

Podlaskie Voivodeship

p

2.4 ± 4.68

3.7 ± 5.3

p < .001

3.4 ± 2.18

3.33 ± 2.15

p = .463

rural areas may have limited access to a neurologist and diagnostic tests. Furthermore, immunomodulatory treatment of MS in northeastern Poland took place for many years in only 1 centre at the Department of Neurology of the Medical University of Bialystok. Therefore, in 2016, two new centres for the treatment of patients with MS opened in this region, which improved access to immunomodulatory treatment. Additionally, in these centres patients have access to a wide range of clinical specialists, which is very important to ensure the health and quality of life of patients with MS. In the Norwegian study, researchers demonstrated that the average time interval between onset and diagnosis of MS declined from a median 21 years between 1953 and 1957–1.3 years between 2003 and 2007 (Grytten et al., 2016). The shortening of this period was associated with greater availability of MRI machines and the use of revised McDonald diagnostic criteria. Currently, these criteria allow for a diagnosis to be made at an earlier stage in patients with typical clinically isolated syndrome (CIS) after the first MRI of the brain, if we prove dissemination in time and space (Polman et al., 2011). Additionally, in the Podlaskie Voivodeship, the time from symptom onset to diagnosis was shorter in the group of men compared with women. Analysis of the MSBase registry showed that men with relapsing-remitting MS had faster and shorter time-to-EDSS points 3 and 6 in comparison with a group of women (Kalincik, 2015). It has also been shown that men are more likely to develop pyramidal, cerebellar and brainstem relapses, of which pyramidal and cerebellar relapses pose a relatively higher risk of incomplete remission; women are more prone to visual and sensory relapses, which are relatively more likely to recover completely (Kalincik, 2015). It is most likely that in the northeastern region of Poland men are diagnosed early because of the pronounced disease onset. In the study group, disability evaluated by EDSS was approximately 3 points and was comparable with other Polish studies (Brola et al., 2016; Potemkowski and Jasińska, 2015; Kulakowska et al., 2010; Pierzchala et al., 2015). A similar result was obtained in a German study, in which the average EDSS score was 3.5 (group studied: 5445 patients) (Flachenecker et al., 2008). The presence of various forms of MS in our study was comparable to other Polish researchers and neighbours (Brola et al., 2016; Potemkowski and

5. Conclusions This is the first data that obtained the level of MS prevalence in Poland. The data confirm that Poland is a high-risk area for MS. In comparison with previous small epidemiologic studies from different regions of Poland, MS prevalence has risen in recent years. The results indicate a need for further long-term epidemiological studies to improve the quality of healthcare in Poland. The key task for all neurologists specialising in MS patient care and treatment is to create a Polish national registry of multiple sclerosis patients, which would include patients from the entire country. Authors’ declaration form The authors submit the work titled: Prevalence of multiple sclerosis in Poland’’ for publication in “Multiple Sclerosis and Related Disorders” and represent that: 1. The work has not been published elsewhere (other than as an abstract of conference proceedings). 2. The work is not currently under consideration for publication in other journals. 3. The work does not infringe on copyright of other parties. 4. All authors (as mentioned below) have read the work and accepted its submission for publication. 5. The heads of the institution where the work was created accept its submission for publication. Conflicts of interest The authors declare that no conflicts of interest exist in relation to the published work. 1: Katarzyna Kapica-Topczewska 54



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Waldemar Brola Malgorzata Fudala Joanna Tarasiuk Monika Chorazy Katarzyna Snarska Jan Kochanowicz Alina Kulakowska

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