sidering the mean number of diseases on the level of
the three-digit ICD-10. Additionally, Figure 2 repres-
ents the mean number of physicians per patient and
quarter. It has to be noted that out of ICD-10 Chapter
XIV (Diseases of the genitourinary system), Chap-
ter XV (Pregnancy, childbirth and the puerperium),
Chapter XXI (Factors influencing health status and
contact with health services) and Chapter XXII (Co-
des for special purposes) were excluded in the analy-
sis to avoid gender asymmetry and bias caused by ad-
ministration. Age and gender dependent differences
in drug descriptions are considered while matching
MRG and ICD-10 (standardization). After determina-
tion of a main MRG and ICD group for each patient,
we get a n-dimensional vector of age dependent frac-
tions of diseases (n as the number of MRG or ICD
groups). The relationship messured by Manhattan di-
stances of such vectors and the age is of interest. The
Manhattan distances monotonically increase up to a
certain also age dependent distance. The reason is that
there are characteristic disease profiles for each age.
Differences increase if gender is included. If it would
be possible to get age information from ICD or MRG
vectors, we can determine the
”
biological age“ of po-
pulation subgroups. One can apply this to existing ins-
urance or social groups.
2 MATERIAL AND METHOD
We utilized prescription and diagnosis data of the
most northern federal state of Germany (Schleswig-
Holstein) from quarters 3/2015 till 2/2016. The analy-
sis is related to patients, quarters and physicians. That
means, that a patient is counted as much as pairs of
quarters and physicians appear. With this background
there are 8.645 Million patients in the drug prescrip-
tion data and 11.117 Million patients in the ICD-10
data.
The C-related programming language awk is used
for the computations. The visualization was done in
Mathematica by Wolfram Reasearch and Microsoft
Excel.
As stated in the introduction, the basic MRG is de-
termined by the ATC3 (four characters) with the hig-
hest costs with respect to patient, quarter and physi-
cian using prescription data. Thus, only patients with
drug prescriptions can get a MRG. In analogy to the
DRG system in inpatient care the basis MRG is exten-
ded by a degree of severity determined by age, multi-
morbidity (measured by polypharmacy) and prescrip-
tion intensity.
Hence, relations between MRG and ICD-10 co-
des with respect to multimorbidity are of interest. In
the first step we consider patient with one ATC and
one ICD-10 only. The resulting pairs provide ordered
lists of ICD-10 per MRG and vice versa. Although
the vast majority of drugs is prescribed in the field of
multimorbid patients, we can use the obtained lists for
additional considerations regarding all patients.
Let q
m
(a,s) be the fraction of patients within a
certain MRG m and certain age group a in 5 year
classes and a certain gender value s and q
∗
(a,s) the
respective fraction within all patients with drug pres-
criptions. Furthermore let p
m,i
(a,s) be the fraction of
patients with a certain diagnosis i within all patients
with MRG m, with age and gender values a and s.
Then
p
1
(m,i) := p
m,i
(∗,∗) =
∑
a,s
p
m,i
(a,s)q
m,i
(a,s)
is the fraction of patients with ICD i within the group
of all patients with MRG m. We compare it with the
respective fraction of patients with ICD-10 i within
all patients with drug prescriptions including age and
gender standardization:
p
2
(m,i) := p
std
m,i
(∗,∗) =
∑
a,s
p
∗,i
(a,s)q
m,i
(a,s).
Without age standardization we get the fraction of pa-
tients with ICD i as
p
3
(∗,i) := p
∗,i
(∗,∗) =
∑
a,s
p
∗,i
(a,s)q
∗,i
(a,s).
The last value may be of interest if there are age rela-
ted prescription restrictions with certain exceptions.
The drug related grouping is done on the physican
group level. Looking at medical disciplines or specia-
lists would give different results. The research sub-
ject determines which point of view is more relevant.
The algorithm is identifying diagnoses leading to a
higher probability of aquiring a certain MRG. That
means if a certain diagnosis i is relevant for a given
MRG value m, we should demand p
1
(m,i) > p
2
(m,i)
or weaker p
1
(m,i) > min(p
2
(m,i), p
3
(∗,i)). This re-
strictions strongly limit the number of diagnoses posi-
tively connected with any given MRG m. The benefit
of any of ICD i with respect to MRG m is measu-
red absolutely by p
1
(m,i) − p
3
(m,∗) or relatively by
p
1
(m,i)/p
3
(∗,i). Resulting diagnoses can be ranked
by the relevance for every MRG considered. Out of all
diagnoses of a patient with a certain MRG we select
the highest ranking in the consideration mentioned
before. If a matching diagnosis does not exist, we re-
peat the consideration disregarding physician groups
(i.e. general practitioners, surgeons and psychiatrists).
If there is no matching at all, it is likely a problem
due to documentation, i.e. a prescription of insulin wi-
thout coding a diagnosis of diabetes.
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