Ukrainian migrants’ and war refugees’ admissions to hospital: evidence from the Polish Nationwide General Hospital Morbidity Study, 2014–2022

Baseline data review

According to the NGHMS, 13,024 Ukrainian citizens were admitted to Polish hospitals (except for psychiatric facilities) in the analysed period, including 5,676 men and 7,348 women. 6,728 persons (51.7%) were admitted to hospital after the outbreak of war (24.02.2022), including 2534 men and 4194 women (Table 1).

The mean age of patients in the entire analysed period was 28.9 ± 0.2, and the median age was 28 years. After 24.02.2022, the age structure of patients changed (Fig. 1). The mean age of the hospitalized persons decreased from 33.6 ± 0.2 years to 24.6 ± 0.3 years, the median fell from 32 to 17 years as a result of the increase in the number of young patients due to the influx of a large number of children to Poland. Before the outbreak of the war, the majority (50.4%) of hospitalized patients under 18 were newborns, currently their share has decreased to 10.2%. The average age of hospitalized children (0–17 years) increased from 4.2 ± 0.2 years to 5.9 ± 0.1 years; the median increased from 0 to 5 years. The average age of hospitalized adults increased from 38.2 ± 0.2 years to 43.9 ± 0.3 years, whereas the median increased from 35 to 39 years.

Before the war, the share of men and women was almost the same (49.9% vs 50.1%), with boys clearly dominating among paediatric patients (62.5%), and women being slightly more predominant among adults (52.2%) (Table 1). After 24.02.2022, an increase in female patients was observed (62.3%). Women constituted up to 79.7% of the hospitalized adults, while the sex disproportion among children decreased (the share of boys was 54.6%). The changes in the gender distribution were statistically significant, both in the group of children (p < 0.001) and adults (p < 0.001).

Frequency and structure of hospitalizations

Before the outbreak of the war, the average of 2.1 person/day were admitted to hospital, and after 24.02.2022 this number increased to 21.6 patients a day. Considering the subgroup of children, before the war 0.3 child was admitted to hospital per day, and after the outbreak of the war there were 11.0 child hospital admissions/day. Regarding adult patients, 1.8 persons and 10.7 persons were admitted to hospital before and after 24.02.2022, respectively. Before 24.02.2022 the most common causes of hospitalization among Ukrainian citizens in Poland were injuries and poisoning (ICD-10: S00-T98), which concerned over a quarter of all patients (26.1 [25.1- 27.2]%) (Table 2).

Second most frequently reported health problems were related to pregnancy, childbirth and the puerperium (O00-O99), which concerned 18.4 [17.5–19.4]% of patients; and they were followed by the causes defined as factors influencing the state of health (Z00-Z99), which concerned 8.4 [7.7–9.1]% patients, including liveborn infants (Z38), which amounted 45.4% of hospitalizations in this group of causes and 3.9 [3.4–4.4]% of all hospitalization cases; as well as chemotherapy (Z51.1), which concerned 34.0% in this group of causes and 2.9 [2.5–3.4]% of all hospitalization cases. Neoplasms (C00-D48) were the fourth most frequent cause of all hospitalizations (6.3 [5.7–6.9]%).

After February 24, 2022, the structure of the causes of hospitalization changed significantly (Table 2). Over 1,000 patients (14.9 [14.1–15.8]%) were hospitalized for pregnancy, childbirth and the puerperium (O00-O99). Symptoms, signs and abnormal clinical and laboratory findings (R00-R99) were the second most frequently reported causes of hospitalization (11.9 [11.1–12.6]%), the majority of which (60.3%) were related to digestive system symptoms (R10-R19), and fever of other and unknown origin (R50) (12.8%), which were the cause of 7.1 [6.5–7.8]% and 1.5 [1.2–1.8]% of all hospitalizations, respectively. The third most significant cause of hospitalizations were infectious and parasitic diseases (A00-B99) (11.0 [10.3–11.7]%), and the fourth one—injury, poisoning and certain other consequences of external causes (S00-T98) (9.3 [8.6–10.0]%).

The observed change in the distribution of the causes of hospitalization is primarily a consequence of changes in the age of the patients. Before February 24, 2022, the vast majority (86.3%) of Ukrainian citizens hospitalizations in Poland concerned adults. Problems characteristic of this age group (Table 3), i.e., injuries (S00-T98), causes related to motherhood (O00-O99) and neoplasms (C00-D48), dominated among all patients.

After the outbreak of the war 50.7% of the hospitalized were patients under 18 years of age (13.7% before the outbreak of the war). The causes prevalent among children are dominant among all patients, and these are infectious and parasitic diseases (A00-B99) (mainly viral and other specified intestinal infections (A08), other gastroenteritis and colitis of infectious and unspecified origin (A09)), symptoms, signs and abnormal clinical and laboratory findings (R00-R99) (mainly digestive system disorders (60.0%) and fever of unknown origin (18.0%)), and diseases of the respiratory system (J00-J99) (Table 4).

The share of hospitalizations related to maternal or obstetric causes (O00-O99) decreased by 3.5 percentage points (pp) in the group of all patients (p < 0.001, Table 2), and by over 11 pp in the group of women (from 36.7 [35.1–38.4]% to 24.0 [22.7–25.3]%; p < 0.001; Table 3). Eleven cases of hospitalizations were recorded for female patients under 18 years of age for this group of causes (Table 4), which concerned exclusively adult women in the period before 24.02.2022.

Apart from changes related to the patients’ age structure after the war outbreak, differences in the frequency of hospitalizations related to particular diseases in both age groups were observed. This effect is particularly visible among children and adolescents. In paediatric patients, the prevalence of infectious and parasitic diseases (A00-B99) increased by over 17 pp, which is statistically significant (p < 0.001), similar to the group of adult patients (from 0.6% to 1.0%; p = 0.026). The share of hospitalizations related to COVID-19 also increased significantly, by almost 3 pp (p < 0.001). Since February 24, 2022 (which is after the peak of the pandemic in Poland), 97 children were hospitalized for COVID-19 (before this date only one child was hospitalized). A statistically significant increase in the frequency of hospitalizations for this reason (by almost 1 pp; p < 0.001) was also observed in the group of adults.

The prevalence of hospitalizations due to diseases of the respiratory system and diseases of the digestive system increased significantly among children, by almost 8 pp (p < 0.001) and 2 pp (p = 0.011), respectively. This was not observed in adults. Additionally, in children the share of hospitalizations for symptoms, signs and abnormal clinical and laboratory findings (R00-R99) increased by more than 12 pp, where digestive system disorders and fever of unknown origin were predominant. For adults this effect was slighter (the share of hospitalization due to R00-R99 increased by almost 2 pp) but also statistically significant (p = 0.004).

The share of hospitalizations due to neoplasms (C00-D48) increased by almost 5 pp in adults (p < 0.001). Before the war outbreak, in an 8-year period 178 cases of adult hospitalizations were recorded due to chemotherapy (Z51.1) (3.3 [2.8–3.8]% of the total number), after its outbreak, in less than a year – 193 (5.8 [5.2–6.4]%). Adult patients hospitalized due to cancer (C00-D48 and Z51.1) are mostly females (72.1% before the war and as many as 85.6% after its outbreak; p < 0.001). The share of children hospitalized for neoplasms increased insignificantly (by 0.7 pp). As a result, the share of neoplasms in the total number of hospitalizations increased by almost 2 pp (p < 0.001).

The share of hospitalizations due to injuries (S00-T98) decreased by 20.1 pp (p < 0.001) in adults, which may be related to the change in the age structure of the Ukrainians in Poland. Before 24.02.2022, patients over 60 years of age accounted for only 8.0% of hospitalized adults, whereas after the outbreak of the war they constituted 22.1%. The change in the age structure may also justify a statistically significant (p < 0.001) decrease in the share of musculoskeletal system diseases (M00-M99) that require hospitalization, which are typical for physical workers. An increase in the share of hospitalizations due to injuries was observed in children and adolescents (by 3.0 pp; p = 0.005).

In-hospital fatality

In the analysed period 96 of 13,024 patients (0.7%) died in hospital. These patients were most often hospitalized due to the circulatory system diseases (I00-I99) (45%), neoplasms (C00-D48) (13%) and injuries (S00-T98) (10%). In-hospital fatality among all patients before February 24, 2022, was 0.9%, whereas after the outbreak of the war it was 0.6%; the difference is statistically significant (p = 0.017). In both analysed periods, the deceased were most often hospitalized due to the diseases of the circulatory system (45% for both cases). There were 8 children among the deceased. The mortality rate decreased in this group, it amounted to 0.6% and 0.1% for the two periods, respectively—difference is statistically significant (p = 0.011). After the outbreak of the war, in-hospital fatality in adults insignificantly increased from 1.0% to 1.1%.