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Panteli et al. BMC Health Services Research (2023) 23:938
https://doi.org/10.1186/s12913-023-09929-z BMC Health Services Research
*Correspondence:
Dimitra Panteli
Full list of author information is available at the end of the article
Abstract
Background The delivery of health services around the world faced considerable disruptions during the COVID-19
pandemic. While this has been discussed for a number of conditions in the adult population, related patterns have
been studied less for children. In light of the detrimental effects of the pandemic, particularly for children and young
people under the age of 18, it is pivotal to explore this issue further.
Methods Based on complete national hospital discharge data available via the German National Institute for
the Reimbursement of Hospitals (InEK) data browser, we compare the top 30 diagnoses for which children were
hospitalised in 2019, 2020, 2021 and 2022. We analyse the development of monthly admissions between January
2019 and December 2022 for three tracers of variable time-sensitivity: acute lymphoblastic leukaemia (ALL),
appendicitis/appendectomy and tonsillectomy/adenoidectomy.
Results Compared to 2019, total admissions were approximately 20% lower in 2020 and 2021, and 13% lower in
2022. The composition of the most frequent principal diagnoses remained similar across years, although changes
in rank were observed. Decreases were observed in 2020 for respiratory and gastrointestinal infections, with cases
increasing again in 2021. The number of ALL admissions showed an upward trend and a periodicity prima vista
unrelated to pandemic factors. Appendicitis admissions decreased by about 9% in 2020 and a further 8% in 2021 and
4% in 2022, while tonsillectomies/adenoidectomies decreased by more than 40% in 2020 and a further 32% in 2021
before increasing in 2022; for these tracers, monthly changes are in line with pandemic waves.
Conclusions Hospital care for critical and urgent conditions among patients under the age of 18 was largely upheld
in Germany during the COVID-19 pandemic, potentially at the expense of elective treatments. There is an alignment
between observed variations in hospitalisations and pandemic mitigation measures, possibly also reflecting changes
in demand. This study highlights the need for comprehensive, intersectoral data that would be necessary to better
understand changing demand, unmet need/foregone care and shifts from inpatient to outpatient care, as well as
their link to patient outcomes and health care efficiency.
How did the COVID-19 pandemic affect
inpatient care for children in Germany?
An exploratory analysis based on national
hospital discharge data
Dimitra Panteli1,2*, Nicole Mauer2, Florian Tille3 and Ulrike Nimptsch1
Page 2 of 13Panteli et al. BMC Health Services Research (2023) 23:938
Introduction
The COVID-19 pandemic has caused substantial dis-
ruptions in the delivery of health services across all ser-
vice areas and delivery platforms around the world [1].
Drops in physician contacts and non-COVID-19 hospital
admissions have been reported for several conditions and
a range of countries [2–4].
These disruptions were likely influenced by a range of
both supply and demand-side factors. The high num-
bers of COVID-19 patients put unprecedented pressure
on health systems. As a result, a range of measures were
implemented to ensure adequate capacities for COVID-
19 care and minimise exposure of those seeking care for
other reasons [5]. Routine visits and elective procedures
were often postponed or cancelled on all levels of care,
and post-surgery and palliative care services were discon-
tinued [5]. At the same time, people may have refrained
from or delayed seeking in-person medical support to
avoid exposure to SARS-CoV-2. Contractions in emer-
gency department admissions for life-threatening con-
ditions, such as stroke and myocardial infarction, have
been reported and could impact health outcomes [2, 4].
The majority of research on the disruption of health
care services during the COVID-19 pandemic has
focused on the adult population [2–4]; less attention
seems to have been paid to paediatric care. However,
there is evidence from different countries on delayed
presentations to paediatric assessment units and gen-
eral paediatric care [6, 7], reductions in hospital admis-
sions [8] and emergency department visits [9], declining
immunisation rates [10], as well as an increase in severe
cases of certain conditions such as new onset diabetic
ketoacidosis for type 1 diabetes [11]. These patterns are
also reflected in findings from Germany for the first wave
of the pandemic [12].
The above observations have been raising concerns
about access to appropriate and timely care for children
during the COVID-19 pandemic and in its aftermath.
For some of the observed phenomena, it remains unclear
whether they reflect a risk for patients due to unmet care
needs, a correction of previous overprovision or ineffi-
cient provision of services, or both. Against the backdrop
of the detrimental effects of the COVID-19 pandemic
and its implications, particularly on those under the age
of 18 [13], it is pivotal to explore this issue further.
This study aims to compare hospitalisations for chil-
dren before and during the COVID-19 pandemic using
complete national data from German hospitals and
explore potential differences in patterns for conditions
and interventions with different levels of urgency and
severity. It investigates the top 30 diagnoses for which
children were admitted to German hospitals in 2019,
2020, 2021 and 2022 and then zooms into three different
tracers (acute lymphoblastic leukaemia, ALL; appendi-
citis; tonsillectomy/ adenoidectomy) to provide prelimi-
nary insights on the relationship between changes in
admission rates and time-sensitivity of care.
Germany is a federal republic; lockdown measures
during the COVID-19 pandemic were mandated by the
national government but implemented at the federal
state level, resulting in regional and local variation. The
first national lockdown was implemented in mid-March
2020, with social distancing measures persisting at least
until early June 2020, and longer in some federal states.
The second national lockdown was preceded by a “light”
lockdown which came into force on 2 November 2020.
Restrictions were hardened in mid-December 2020 and
lasted until March 2021. This was followed by revised
legislation on health protection that allowed for further
flexibility in implementing public health and social mea-
sures across the federal states as of April 2021 [14, 15].
During lockdowns, hospitals were advised to postpone
elective non-urgent treatments to preserve capacity for
the treatment of patients with COVID-19 [5, 16, 17].
Most federal-level measures were lifted following legis-
lative changes in March 2022; the new legal framework
also defined narrower scopes for state-level measures,
focusing on the protection of vulnerable groups [18].
Methods
Data
We used complete national hospital discharge data col-
lected according to §21 of the Hospital Remuneration
Act (Krankenhausentgeltgesetz) [19] (the so-called “DRG
data”) available through the open access data browser of
the German National Institute for the Reimbursement of
Hospitals (Institut für das Entgeltsystem im Krankenhaus,
InEK), to which all German hospitals routinely report
performance and billing data (see Sect.1 of the online
Appendix). The data browser was created in response to
the COVID-19 pandemic and provides access to aggre-
gated discharge data on all inpatient cases discharged
from hospitals in 2019, 2020, 2021 and 2022 including
inter alia information on principal and secondary diagno-
ses (coded according to ICD-10, German modification),
performed procedures (coded according to the German
Operation and Procedure Classification “OPS”), as well
as limited sociodemographic indicators (age group, sex)
and other relevant clinical information, such as aver-
age length of hospital stay (ALOS) and distribution of
Keywords COVID-19, Coronavirus, Paediatric, Child hospitalisations, Hospital admissions, Discharge data, Germany,
Appendicitis, Acute lymphoblastic leukaemia, Tonsillectomy, Adenoidectomy
Page 3 of 13Panteli et al. BMC Health Services Research (2023) 23:938
hospitalisations by hospital bed capacity [19]. The data
captures cases with inpatient stays but not those who
were treated as outpatients (e.g., for emergency care or
day surgery).
Data extraction
We obtained data for children aged 28 days to 17 years
who were admitted to German hospitals between 1
January 2019 and 31 December 2022 via the InEK data
browser interface (https://datenbrowser.inek.org/). We
first extracted data on the total number of cases admitted
between 1 January and 31 December each year to identify
overall changes in volume and the breakdown of annual
cases by principal diagnosis. From among the 30 most
frequent diagnoses represented each year, we selected
three tracers with varying degrees of time-sensitivity: (a)
ALL without stated remission (acute essential care [20]);
(b) appendicitis (acute care with a potential alternative to
immediate hospitalisation [21]); and (c) tonsillectomy/
adenoidectomy (planned care to address chronic condi-
tions [22]). These tracers were selected precisely because
they could be considered to adequately reflect these dif-
ferent categories of time-sensitivity; this was not appli-
cable for most of the other frequent diagnoses identified
in the previous step. We extracted monthly admissions
for (a) cases with ALL not having achieved remission
(identified via ICD-10 principal diagnosis code C91.00);
(b) cases with appendicitis (see Table1 for ICD-10 prin-
cipal diagnosis codes) and cases with appendicitis who
underwent an appendectomy (identified via the same
ICD-10 principal diagnoses plus relevant OPS procedure
codes); and (c) cases who underwent a tonsillectomy and/
or adenoidectomy (identified via OPS procedure codes,
see Table1). First data samples to conceptualise the study
were downloaded in April 2021; data for the final analy-
sis were extracted between 15 and 28 February 2022 for
2019 and 2020 and between 18 and 20 May 2023 for 2021
and 2022.
Data analysis
Data was analysed using Microsoft Excel. Annual total
case numbers for 2019, 2020, 2021 and 2022 were com-
pared and differences were calculated (absolute numbers
and percent changes). The 30 principal diagnoses (three-
digit ICD-10 categories) with the highest number of
cases were listed for each year, and differences to previ-
ous years were calculated (absolute numbers and percent
changes). For the three tracers (ALL, appendicitis/appen-
dectomy, and tonsillectomy/adenoidectomy), annual and
monthly data across the three years were compared and
plotted graphically. Differences in sex, age group, ALOS,
patient clinical complexity level (PCCL; a measure of
the cumulative effect of a patient’s complications and
comorbidities calculated for each episode of care), and
hospital size were explored descriptively.
Results
Overall case numbers and most frequent reasons for
hospitalisation
The total number of admissions decreased by more than
20% in 2020 compared to 2019 (see Fig. 1). In 2021,
admissions increased by 2.7% compared to 2020 but
remained 19.5% lower than in 2019. In 2022, admissions
increased by 8.8% compared to 2021, and stayed 12.7%
below 2019 levels. Annual ALOS increased by 0.1 days in
2020 and then remained stable before returning to 2019
levels in 2022 (in days, 2019: 3.2; 2020: 3.3; 2021: 3.3;
2022: 3.2). No obvious patterns emerged in the composi-
tion of annual admitted cases regarding sex, age group or
patient complexity (see Sect.2 of the online Appendix).
Figure1 shows the principal diagnoses for which chil-
dren received inpatient care in 2019, 2020, 2021 and
2022. Relative changes compared to 2019 are colour-
coded to highlight decreases (red) or increases (green).
The overall composition of the 30 most frequent diag-
noses remained similar across years, but changes in rank
can be observed.
For admissions due to respiratory (e.g., J20, J06, J18,
J21) and gastrointestinal infections (e.g., A09, A08),
decreases between 30% and 70% were observed in 2020
compared to 2019. For some of these conditions, admis-
sions in 2021 remained lower than 2019, but increased
compared to 2020 (J20, J06, A09, A08), while for others,
admissions in 2021 surpassed 2019 values (e.g., J12 by 7%
and J21 by 28%). Admissions for all respiratory and gas-
trointestinal infections were higher in 2022 compared to
2021, except for acute bronchiolitis (J21); for some condi-
tions (e.g., J06 and A08), admissions in 2022 were more
than 20% higher than in 2019. Hospitalised influenza
cases increased by nearly 20% in 2020 compared to 2019,
and almost disappeared in 2021 (there were 172 hos-
pitalised cases with an ICD-10 code J10 in 2021, a 98%
reduction compared to the two previous years); admis-
sions increased again in 2022, surpassing the 2019 value
by 65%.
Among hospitalisations for the most frequent non-
communicable conditions or clinical signs, decreases of
over 20% compared to 2019 were observed in 2020 for
chronic diseases of the tonsils and adenoids (43%, K35),
mental and behavioural disorders due to use of alcohol
(36%, F10), abdominal and pelvic pain (28%, R10), syn-
cope and collapse (28%, R55) and certain functional gas-
trointestinal disorders (22%, K59). In 2021, admissions
for most of these conditions decreased by less than 10%
or not at all compared to 2020 (thus remaining at levels at
least 20% lower than 2019), with the exception of admis-
sions for chronic diseases of the tonsils and adenoids,
Page 4 of 13Panteli et al. BMC Health Services Research (2023) 23:938
2019 2020 2021 2022
Acute lymphoblastic leukaemia1
Hospital admissions, n 10,119 10,246 10,661 12,369
Age, %
28 d – 1 yo2
1–2 yo
3–5 yo
6–9 yo
10–15 yo
16–17 yo
1.62
14.58
33.14
20.87
24.88
4.91
0.61
16.28
35.83
20.05
21.16
6.07
1.81
17.91
32.49
20.34
21.53
5.93
0.70
19.44
32.25
20.62
21.76
5.24
Sex, %
Male
Female
56.61
43.39
58.65
41.35
57.59
42.41
57.26
42.74
PCCL, %3
0
1–6
60.28
39.72
57.36
42.64
58.84
41.16
65.75
34.25
ALOS, mean ± SD 5.5 ± 9.7 5.6 ± 8.9 5.5 ± 8.8 5.7 ± 11.1
Appendicitis (underwent appendectomy)4
Hospital admissions, n 22,454 (20,885) 20,363 (19,040) 18,771 (17,384) 18,086 (16,555)
Age, %
28 d – 1 yo
1–2 yo
3–5 yo
6–9 yo
10–15 yo
16–17 yo
0.01 (0.01)
0.90 (0.72)
4.66 (4.39)
17.59 (17.35)
53.18 (53.19)
23.67 (24.34)
0.04 (0.03)
0.91 (0.74)
5.03 (4.78)
19.31 (19.02)
52.22 (52.30)
22.49 (23.13)
0.08 (0.07)
0.86 (0.70)
5.72 (5.44)
19.80 (19.66)
50.99 (50.95)
22.55 (23.17)
0.06 (0.05)
0.78 (0.69)
5.52 (5.19)
20.25 (19.91)
50.82 (50.66)
22.56 (23.49)
Sex, %
Male
Female
50.90 (50.98)
49.09 (49.01)
52.33 (52.44)
47.66 (47.55)
53.01 (53.26)
46.99 (46.73)
53.88 (54.07)
46.10 (45.90)
Principal diagnosis, %
K35.30, K35.8, K36, K37 - uncomplicated appendicitis
K35.2, K35.31, K35.32 - complicated appendicitis
82.53 (82.52)
17.47 (17.48)
80.40 (80.06)
19.60 (19.94)
79.84 (79.47)
20.16 (20.53)
78.92 (78.34)
21.08 (21.66)
PCCL, %
0
1–6
83.99 (83.61)
16.01 (16.39)
82.33 (81.99)
17.67 (18.03)
81.09 (80.64)
18.91 (19.37)
79.09 (78.44)
20.89 (21.57)
ALOS, mean ± SD 4.3 ± 2.8 (4.3 ± 2.7) 4.3 ± 2.9 (4.3 ± 2.8) 4.2 ± 2.8 (4.2 ± 2.7) 4.2 ± 2.9
(4.2 ± 2.8)
Tonsillectomy and/or Adenoidectomy5
Hospital admissions, n 51,370 29,148 19,864 34,174
Age, %
28 d – 1 yo4
1–2 yo
3–5 yo
6–9 yo
10–15 yo
16–17 yo
0.65
19.51
46.97
16.42
10.71
5.74
0.82
18.71
47.49
16.07
10.49
6.42
1.27
22.97
45.86
12.03
10.01
7.85
0.72
19.46
53.90
13.22
7.15
5.56
Sex, %
Male
Female
56.02
43.97
56.52
43.47
55.96
44.00
57.64
42.32
Principal diagnosis, %
J35.2 (hypertrophy of adenoids)
J35.3 (hypertrophy of tonsils & adenoids)
J35.0 (chronic tonsillitis & adenoiditis)
J35.1 (hypertrophy of tonsils)
Other principal diagnosis
29.48
28.68
17.26
11.99
12.52
26.04
29.54
17.61
13.48
13.33
27.76
27.25
16.35
13.89
13.27
31.95
30.22
12.52
12.65
11.60
Table 1 Characteristics of inpatient cases with acute lymphoblastic leukaemia, appendicitis/appendectomy, and tonsillectomy/
adenoidectomy
Page 5 of 13Panteli et al. BMC Health Services Research (2023) 23:938
which decreased by another 33%. In 2022, admissions
for conditions of the tonsils and adenoids increased
compared to 2021 and 2020 but remained 33% below
2019 values; for the other four conditions, admissions
either increased slightly compared to 2021 (R10, R55)
or decreased further (F10, K59), all remaining at least
20% below 2019 levels. For some serious acute condi-
tions, such as acute tubulo-interstitial nephritis (N10),
the number of cases decreased by less than 5% in 2020,
and kept decreasing over the observation period (2022
admissions 15% below 2019); for others, such as ALL
(C91), admissions initially increased by less than 5% and
kept increasing over the observation period (2022 admis-
sions 22% above 2019). Admissions due to diabetes mel-
litus (E10) decreased by 15% in 2020 compared to 2019,
and then gradually returned to 2019 levels by 2022.
Injuries of the head and extremities remained among
the most frequent reasons for hospitalisation during
the observation period (see Fig.1). Admissions due to
intracranial injuries and superficial injuries of the head
decreased by 21% and 12% respectively in 2020 compared
to 2019 and remained stable in 2021. In 2022, admissions
due to intracranial injuries remained 19% lower than
2019, while admissions due to superficial head injuries
decreased further to 20% below 2019 levels.
Acute lymphoblastic leukaemia (ALL)
The total number of children hospitalised for ALL not
having achieved remission (C91.00) increased by 1.3%
from 2019 to 2020, by 4.1% from 2020 to 2021, and by
13.8% from 2021 to 2022 (see Table 1). Monthly case
numbers show that fluctuations throughout the year fol-
lowed four “peaks” across the observation period, in Jan-
uary, April, July, and October of each year (see Fig.2 and
Figure S1 in the online Appendix for relative changes).
The composition of ALL cases regarding sex, age group
and patient complexity shows variations throughout the
observation period (see Table1 and Sect. 3 of the online
Appendix). ALOS ranges from 3.2 days (December 2019
and December 2022) to 9.7 days (October 2022), with a
median of 5.6 days. The share of cases treated in large
tertiary hospitals of 1000 beds or more decreased by
approximately 10% points in 2020 (see online Appendix),
while the share of ALL cases admitted in hospitals of
under 1000 beds increased; admissions in hospitals with
1000 beds or more increased again in 2021 and 2022.
Appendicitis and appendectomy
Hospital admissions for children diagnosed with appen-
dicitis decreased by 9.3% between 2019 and 2020, by
7.8% between 2020 and 2021 and by 3.7% between 2021
and 2022 (see Table1). Total monthly admissions due to
appendicitis were below 2019 levels for the duration of
the observation period with the exception of August 2020
(see Fig.3 and Sect. 4 of the online Appendix).
There were more male patients hospitalised for appen-
dicitis than females across all years; the proportion
of male cases increased over the observation period
(Table 1). Across years, most admissions regarded
patients aged 10 to 15 years. Among cases admitted for
appendicitis, the vast majority underwent appendectomy
(2019: 93.0%, 2020: 93.5%, 2021: 92.4%, 2022: 91.5%).
The majority of hospitalised appendicitis cases had an
uncomplicated clinical presentation based on ICD-10
diagnosis [23] (see Figs.3 and 2019: 82.5%, 2020: 80.4%,
2021: 79.8%, 2022: 78.92%). The share of cases with com-
plications such as generalised peritonitis, abscess forma-
tion, rupture or perforation increased across years (2019:
17.5%, 2020: 19.6%, 2021: 20.2%, 2022: 21.1%). The high-
est relative reductions (≥ 20%) in admissions for uncom-
plicated appendicitis compared to 2019 were observed in
March and May 2020, in January to March, May as well
as October and November 2021 and for most months in
2022, with the exception of August and November; rela-
tive increases in complicated cases were observed for
some months over the observation period, but they only
surpassed 10% of the 2019 value in July 2020 (see Figure
S5 in the online appendix).
The share of cases with low clinical complexity (PCCL
level 0) decreased between 2019 and 2022, while the
share of cases with higher complexity rose from 16.0 to
20.9% in all cases and from 16.4 to 21.6% in cases with
2019 2020 2021 2022
PCCL, %3
0
1–6
93.87
6.13
93.66
6.34
92.43
7.57
93.02
6.98
ALOS, mean ± SD 2.5 ± 2.2 2.5 ± 2.2 2.4 ± 2.1 2.2 ± 2.0
1 Cases with a principal diagnosis of C91.00 (ICD-10)
2 yo = years of age
3 PCCL = Patient Clinical Complexity Level; levels 0 (no comorbidities/complications), 1 (light comorbidities/complications) to 6 (most severe comorbidities/
complications)
4Cases with a principal diagnosis in K35, K36, K37 (ICD-10); cases who underwent appendectomy (principal diagnosis in K35, K36, K37 and procedure code in 5-470,
5-455.3) are shown in brackets
5Cases with a procedure code in 5-281, 5-282, 5-285 (OPS)
Table 1 (continued)
Page 6 of 13Panteli et al. BMC Health Services Research (2023) 23:938
Fig. 1 Thirty most frequent discharge diagnoses for hospitalised children in 2019, 2020, 2021 and 2022
Legend: Shading of percent change numbers is based on the following increments from lighter to darker: 0–10%, 11–25%, 26–50%, > 50%. The three tracers analysed in detail are highlighted in different
colours (blue, yellow, purple); numbers in the table reflect cases for the three-digit ICD-10 categories and thus do not exactly match data in the detailed analysis. Greyed cells denote conditions not appearing
in previous/subsequent years
Page 7 of 13Panteli et al. BMC Health Services Research (2023) 23:938
Fig. 2 Monthly hospital admissions and ALOS for ALL, January 2019 – December 2022
Fig. 3 Monthly hospital admissions for appendicitis by level of complication, January 2019 - December 2022. Note: darker column segments correspond
to complicated cases, lighter segments to uncomplicated cases
Page 8 of 13Panteli et al. BMC Health Services Research (2023) 23:938
appendectomy, respectively. ALOS remained similar
across years (see Table1).
Across all years, small- to medium-sized hospitals
(200–599 beds) hosted most cases, followed by large cen-
tres of 1000 beds and more. Over this period, reductions
in admissions occurred in hospitals with fewer than 400
beds (see online Appendix).
Tonsillectomy and adenoidectomy
The number of cases hospitalised for tonsillectomy and/
or adenoidectomy was 43.2% lower in 2020 compared to
2019, and decreased by a further 31.7% in 2021; in 2022,
cases increased by 72% compared to 2021, but remained
33.5% below 2019 levels (see Table 1). The largest
monthly reductions in 2020 compared to the correspond-
ing months in 2019 were observed in April (82.8%) and
May (55.6%), as well as November (52.2%) and Decem-
ber (62.6%) (see Fig.4 and Figure S8 in the online appen-
dix). Admissions for all months in 2021 remained over
50% below 2019 levels, with the exception of November
(-45.7%); they were also lower than the corresponding
2020 values for most months, except April (+ 83.3%),
November (+ 13.8%) and December (+ 33.0%). In 2022,
monthly admissions surpassed those in 2021 throughout
the year; they remained more than 40% below 2019 until
April, but relative differences diminished to below 40%
from May onwards (see Figure S8 in the online appendix).
The age group with the highest share of tonsillectomies
and/or adenoidectomies was that of children aged 3 to
5 years; small variations in the shares of the remaining
age groups can be observed throughout the observation
period.
In all three years, the most frequent underlying diag-
noses for tonsillectomies and/or adenoidectomies were
hypertrophy of the adenoids (ICD code J35.2), hypertro-
phy of the tonsils with hypertrophy of adenoids (J35.3),
chronic tonsillitis and adenoiditis (J35.0) and hypertro-
phy of the tonsils only (J35.1), adding up to over 85% of
diagnoses for all cases (see Table1).
The share of cases with a PCCL of level 1 and above
increased from 6.1% to 2019 to 7.5% in 2021, and
decreased to 6.98% in 2022. ALOS remained stable in
2020, but decreased by 0.1 days in 2021 and a further 0.2
days in 2022 (see Table1).
The distribution of tonsillectomies and adenoidecto-
mies across hospitals of different sizes remained largely
the same during the observation period; the proportion
of cases treated in the smallest hospitals (less than 200
beds) increased by nearly 3% points (9.9–12.7%) from
2019 to 2021 before declining in 2022 (see Sect.5 of the
online Appendix).
Comparison of changes for ALL, appendicitis, and
tonsillectomies/adenoidectomies
Figure5 plots the monthly admission numbers for the
three tracers against lockdown periods in Germany. It
shows that these periods coincided with decreases in
admissions for tonsillectomies/adenoidectomies and
Fig. 4 Monthly hospital admissions for tonsillectomy/adenoidectomy, January 2019 - December 2022
Page 9 of 13Panteli et al. BMC Health Services Research (2023) 23:938
Fig. 5 Monthly case numbers for ALL, appendicitis and tonsillectomy/adenoidectomy between January 2019 and December 2022 and federal lockdown measures in Germany (state level measures are not
depicted)
Page 10 of 13Panteli et al. BMC Health Services Research (2023) 23:938
appendicitis, but not for ALL. Following the end of the
federal mandate for most pandemic-related restrictions
in March 2022, an increase in monthly admission num-
bers for tonsillectomy/adenoidectomy can be observed;
no similar effect is obvious for appendicitis or ALL.
Discussion
The number of paediatric hospitalisations in Germany
fell by 20% in 2020 compared to 2019. Although admis-
sions increased again slightly in 2021, and again more
substantially in 2022, the number of inpatient cases
did not return to pre-pandemic levels by the end of the
observation period. Similar findings have been reported
in adult populations, with persistent reductions in both
elective and emergency routine hospital care docu-
mented in Germany and worldwide [24, 25]. Previous
work on a sample of German paediatric patients showed
a drop of around 40% for overall admissions and surger-
ies in the first months of the pandemic [12].
Overall, the composition of the most frequent clinical
indications for admission did not change substantially.
However, individual diagnoses displayed important fluc-
tuations throughout the pandemic. In particular, respira-
tory and gastrointestinal infections plummeted in 2020,
likely as a result of COVID-19 restrictions; this confirms
previous findings from the German and international lit-
erature [26, 27]. Remarkably, influenza cases displayed an
initial soar in 2020, as many children were likely admit-
ted on suspicion of a SARS-CoV-2 infection, but sub-
sequently reached a record low in 2021 [26]. Influenza
admissions rose again dramatically in 2022, potentially
reflecting increased susceptibility following the period
of non-exposure due to pandemic mitigation measures
[28] in combination with increased testing activity [29].
The same interpretation could explain increases in other
infectious diseases observed in 2021 and 2022 compared
to 2019. For instance, the considerable rise in admissions
for acute bronchiolitis in 2021, which was largely driven
by an increase in respiratory syncytial virus (RSV) infec-
tions (ICD-10 code J21.5, effect masked in Table1 due
to the aggregation of cases to three-digit ICD-10 catego-
ries), has also been observed elsewhere and linked to the
restrictions implemented to halt viral transmission [30].
The early start of the influenza season in 2022, combined
with increased hospitalisations in children due to RSV
and persistent COVID-19 concerns put European health
systems under duress in winter 2022 [31].
Changes in admissions for non-communicable condi-
tions and injuries in 2020 and 2021 could reflect behav-
ioural changes produced by restrictions such as the
closure of schools and reduced social interactions with
other children [12], or changes in clinical practice in light
of pandemic mitigation measures. For example, admis-
sions due to diabetes mellitus decreased in 2020, and
picked up again in 2021, finally reaching 2019 levels in
2022. For indications with decreases in admissions that
matched or surpassed 2021 levels in 2022 (a year with
fewer pandemic-related restrictions), such as head inju-
ries and functional gastrointestinal disorders, further
analyses should explore the potential link with an evolu-
tion of clinical protocols. Admissions to German hospi-
tals due to behavioural and mental disorders triggered
by alcohol consumption decreased continuously over the
observation period, but it remains unclear whether this is
related to a decrease in alcohol consumption or a rise in
unmet care needs.
Hospitalisation rates for the three tracers were affected
to varying degrees throughout the observation period.
The lack of substantial shifts in ALL hospital admissions
suggests that inpatient services for severe conditions,
such as haematologic cancers, were upheld throughout
the pandemic. The increase in active ALL admissions
over the observation period is in line with data from the
German Childhood Cancer Registry [32], and merits
further investigation. Despite this increase in cases, the
share of ALL patients treated in large tertiary centres
decreased during the pandemic in favour of smaller hos-
pitals, which may reflect the reallocation of patients and
resources implemented as part of the pandemic response.
The four peaks in the distribution of hospitalisations for
ALL consistently observed for every year of the observa-
tion period correspond to the first month of every quar-
ter and could be related to therapeutic regime planning
or other contextual factors.
Observed reductions in appendicitis hospitalisations
in 2020 and 2021 were most pronounced for the months
overlapping with the pandemic mitigation measures
implemented by the government and federal states; how-
ever, admissions remained at least 15% below 2019 levels
for every month in 2022, which might reflect an evolu-
tion in clinical practice towards outpatient management
[33]. There was a slight increase in the proportion of
complicated clinical presentations over the observation
period, with similar findings reported in the literature
[34]. However, without comparable data from ambula-
tory and emergency department settings, it is impos-
sible to judge whether this was due to fear of exposure
to SARS-CoV-2 while seeking care and related delays, or
other factors [35].
The observed reductions in tonsillectomy and/or
adenoidectomy procedures reflect the widespread post-
ponement of elective interventions supported by the
German government in mid-March 2020, while changes
in demand due to concerns about SARS-CoV-2 expo-
sure may also have played a role. These findings are
in line with a population-wide analysis across all age
groups, which also highlights the evolution of clini-
cal practice towards minimally invasive approaches
Page 11 of 13Panteli et al. BMC Health Services Research (2023) 23:938
performed in ambulatory settings [17]. While it is con-
ceivable that the pandemic further accelerated this devel-
opment, the renewed increase in admissions following
the lapse of federal restrictions in March 2022 observed
in our data might suggest otherwise and requires further
investigation.
In general, shifts from inpatient to outpatient treatment
could not be investigated in this study due to the nature
of the data. However, the plausibility of ambulatory care
fully offsetting the observed decreases in inpatient care
is questionable, given that outpatient care visits in Ger-
many also decreased markedly during lockdown periods,
particularly for children, and did not increase substan-
tially overall during the pandemic. A similar pattern can
be observed for outpatient surgery [36].
Our study has several limitations. Given the research
question(s), this was by definition a retrospective design,
and draws on aggregated data based on ICD-10 codes
used for billing purposes. On the one hand, there is a risk
of misdiagnosis that is impossible to account for in such a
design; what is more, admissions motivated by social cir-
cumstances rather than the severity of presentation can-
not be discerned, although this distinction would have
been particularly meaningful to capture in an analysis
like this one. Furthermore, hospital discharge data are
typically prone to entry and codification errors; however,
German hospital billing data are considered fairly reliable
with regard to reimbursement-relevant content [37]. The
DRG data capture all national inpatient cases, with the
exception of cases financed through the statutory insur-
ance for occupational accidents and treated in occupa-
tional health hospitals; as they represent only small case
numbers, the DRG data can be assumed to be virtually
complete. Linkage to outpatient data would require a
more complex methodological approach than the one
adopted here; such analyses could draw on the findings of
this exploratory descriptive study (see below). Since the
InEK data browser only contains pre-pandemic data for
2019, it was impossible to account for particularities in
hospital admission numbers of that year or compare hos-
pitalisation trends over several years, including decreas-
ing tendencies in admissions for appendicitis and/or
tonsillectomies/adenoidectomies before the pandemic.
Additionally, the dataset used for 2022 was still subject
to updates and corrections by submitting hospitals at
the time of writing; this might have biased the results,
but potential changes are not expected to be of a mag-
nitude that would substantially change the overall inter-
pretation of our findings. The data browser only provides
a limited set of sociodemographic indicators, only for
inpatient cases (not patients) and at an aggregate level;
this precludes stratification by specific patient subgroups
as well as following up on individual patients to iden-
tify those with multiple hospitalisations. Thus, the data
available through the data browser does not lend itself
to further inferential analyses, which were therefore not
attempted here. Given the nature of the data, this work
was conceived as an exploratory descriptive analysis to
identify patterns and generate hypotheses; as such, we
did not test differences between years for statistical sig-
nificance. Finally, the three tracers are not representative
of all urgent or elective care in the German health sys-
tem, and our analysis of the most frequent 30 diagnoses
remained superficial, but can provide impetus for further
investigations.
Indeed, follow-up analyses could further explore
changes in the most frequent reasons for admission
for narrower age groups or focus on case distribution
by hospital size for specific indications or indication
groups. What is more, future research should go beyond
pattern description to understand if observed differ-
ences in admission rates have led to adverse outcomes
for paediatric patients during the pandemic; this would
require adequate data. For the German context, this
might entail working with individual sickness funds to
be able to depict the entire patient pathway. Understand-
ing the determinants of observed hospitalisation patterns
requires primary research, especially since the decision
to admit a child can sometimes be motivated by social
circumstances rather than severity of clinical presen-
tation. International evidence indicates inequalities in
healthcare disruptions during the pandemic, both for the
general population [38] and for paediatric care [39]; this
dimension would also be crucial to investigate further in
the German setting.
Conclusions
This is the first nationally complete study capturing all
paediatric inpatient cases in Germany in the immedi-
ate pre-pandemic and pandemic periods. Our study
demonstrates that paediatric care for critical and urgent
conditions was largely upheld, potentially at the expense
of elective treatments. This must be interpreted in the
context of Germany’s health system, which has a large
inpatient sector and relative overcapacity in terms of
hospital beds [40]; it is likely that the situation has been
quite different in other settings. Indeed, there are grow-
ing concerns over looming backlogs of health services,
which threaten to put additional strain on health systems
globally [41]. As policies to address this issue are devel-
oped, particularly understudied and vulnerable groups
like children should stay in focus. This study also dem-
onstrates the need for comprehensive, intersectoral data
that enable a better understanding of changing demand,
unmet need, and foregone care as well as shifts from
inpatient to outpatient care, and their link to patient out-
comes and health care efficiency.
Page 12 of 13Panteli et al. BMC Health Services Research (2023) 23:938
Supplementary Information
The online version contains supplementary material available at https://doi.
org/10.1186/s12913-023-09929-z.
Supplementary Material 1
Acknowledgements
We thank Univ.-Prof. Dr. med. Orlando Guntinas-Lichius und Prof. Dr. med.
Jochen Windfuhr for providing information on the availability of tonsillectomy
and adenoidectomy case numbers in ambulatory care in Germany. We also
thank Dr. Christina Panteli and Dr. med. Christiane Kuhlen for providing clinical
insights into paediatric care.
Authors’ contributions
DP conceived the study. DP and UN developed the methodological approach.
DP, NM and FT had full access to the data, undertook the data analysis, and
take full responsibility for the integrity and accuracy of the analysis. DP, NM, FT,
and UN wrote several drafts and produced the final version of the manuscript.
All authors have approved the final version.
Funding
Open Access funding enabled and organized by Projekt DEAL.
Data Availability
The data used for the analysis are publicly available and freely downloadable
from the German National Institute for the Reimbursement of Hospitals (InEK)
data browser. All analyses have been documented using Microsoft Excel and
will be made publicly available in an open repository prior to publication.
Declarations
Ethics approval and consent to participate
This study was exempt from ethical approval because the data are
deidentified and publicly available for download from the InEK data browser.
Consent for publication
Not applicable.
Competing interests
The authors declare no competing interests.
Author details
1Department of Health Care Management, Technische Universität Berlin,
Strasse des 17. Juni 135, 10623 Berlin, Germany
2European Observatory on Health Systems and Policies, Place Victor Horta
40/30, Brussels 1060, Belgium
3European Observatory on Health Systems and Policies, London School of
Economics and Political Science, Cowdray House, London WC2A 2AE, UK
Received: 29 June 2022 / Accepted: 16 August 2023
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