Belgium: From 3MTM APR-DRG v15 to
v28
a
Peter Heirman, MD,a,1 and Pincé Hilde, MD, PhD b
Head of Medical Registration Department, Centre hospitalier regional de la Citadelle,
Liège, Belgium
b
Head of Medical Registration Department, University Hospital Leuven, Belgium
Abstract.The Federal Department of Health in Belgium relies on the ICD-9-CM coding and
3M™APR-DRG v15 grouping system for its hospital financing. An update of both is necessary. This part of
the study focuses on the differences at the DRG level highlighting the modifications of SOI levels and APRDRG content arising through the conversion of v15 to v28, the implications on hospital financing and the
consequences on the other various areas where the APR-DRG system is applied. A theoretical comparison
was made between both versions on the 2009 national dataset. 3MTM has given full disclosure of its
algorithms for this purpose. Only a handful of DRGs retain the same composition. Some DRGs, regardless of
their names or definition, show high level changes either through rerouting on the SOI level, through changes
of the allocation to an MDC level (e.g. MDC 15 – newborns) or the influenceof new parameters that were
absent in v15 like POA, date of procedures, etc…).
Keywords. APR-DRG, 3MTM, ICD-10-CM, Belgium
Introduction
Belgium has a 30 year old tradition of registration of a Uniform Hospital Discharge
Data Set for inpatients. These data are grouped by a Patient Classification System. The
attribution of the hospital budgets is increasingly based on these data. The Patient
Classification System originally used was the 3MTM APR-DRG v10.0. This version
was updated in July 2002 to the 3MTM APR-DRG v15 and there has not been an update
since. The planned date for the transition from ICD-9-CM to ICD-10-CM/PCS has
been set on January 1st 2015.The15.0 version does not allow the input of ICD-10CM/PCS codes, making a change of grouper version imperative. The first step in this
transition process is the change from v15 to v28. The 28.0 version cannot process
either ICD-10-CM/PCS codes, but its logic is closer to the grouper version that will
eventually be able to so. This paper describes the theoretical and practical comparison
between the 2 grouper versions.
1. Methods
A theoretical comparison was made between the two systems after the full disclosure of
the algorithm by the 3MTMcompany. [1][2].Several specific changes were expected.
1
Corresponding Author.
The Belgium dataset MZG-RHM (Minimale Ziekenhuisgegevens – Resumé
Hospitalier Minimum) 2009-1 (January-June 2009) was subsequently processed with
both versions of the algorithm and the comparison made. The in- and outflow between
different APR-DRGs and the impact of new or deleted APR-DRGs was analyzed.
2. Results
2.1. Theoretical comparison
A first set of differences could be described as a change of clinical coherence. This
implies high level “Major Diagnostic Category (MDC) changes to a large extent. Both
grouper versions contain 25 MDCs. Out of all stays, 1.25% were assigned to a different
MDC for the Belgian national dataset. When including one-day-cases, 22.000
admissions are allocated to a different MDC. The most important changes are discussed
here.
MDC 15 (Newborns and other neonates with conditions originating in the perinatal
period) becomes a smaller category in v28. MDC 15 included in v15 all newborn
babies and neonates with age less than 29 days at the time of admission. The age
definition of MDC 15 v28 was narrowed in order to include only newborn babies,
newborns younger than 8 days at time of admission and a subset of babies with age 814 days with low birth weight having perinatal complications. The objective is to
obtain a more ‘homogeneous MDC’ and remove, for example, all readmissions for
community acquired infections. The result is a substantial shift of hospital stays from
MDC 15 v15 to other MDCs in v28, where they are assigned to more disease-specific
APR-DRGs. Out of all admissions in MDC 15 v15, 96% remain in MDC 15 v28. The
other 4 % move to another MDC in v28. Out of these 4%, the largest group is assigned
to MDC 23 whereas the others were rerouted to MDCs 4, 6, and 18, mainly the
community acquired infections. All hospital stays in MDC 15 v28 originate from MDC
15 v15. MDC 15 faces only an ‘outflow’ through the transition from v15to v28.
MDC 3 v28 contains all craniofacial diseases and disorders. These admissions
were dispersed across MDCs 1, 3, 8, 21 and the tracheostomy DRGs in v15. The
revised title of MDC 3 v28 is now “Ear, Nose, Mouth, Throat and Craniofacial
Diseases and Disorders” as a result of the ‘inflow’ from the MDCs mentioned above.
MDC 3 v28 obtains 2% new hospital stays, previously dispersed among other MDCs in
our dataset. This means an ‘inflow’ of about 2700 admissions. Out of all admissions in
MDC 3 v28, 68% are one-day-cases.
Other important MDC shifts include the redefinition of MDC 21 to ‘Poisonings,
Toxic Effects, other Injuries and other Complications of Treatment’. Most of the injury
diagnoses have moved from MDC 21 to the other more body system specific MDCs 1,
3, 5, 8 and 9. This results in an ‘outflow’ of about 3.300 admissions from MDC 21 v15.
Prematurity diagnoses for older neonates and infants, and orthopedic aftercare
diagnoses were moved to MDC 23 ‘Rehabilitation, Aftercare, Other Factors
Influencing Health Status and Other Health Service Contacts’. As a result, there is an
inflow of about 2800 admissions in MDC 23, mainly day-cases.
At a lower level, some changes occur due to the revision of procedure codes
considered as OR (Operating Room) or non OR-procedures. These codes determine the
assignment to a surgical or medical APR-DRG. The OR-procedures list was narrowed,
for example: an excisional debridement is no longer an OR procedure in v28. In the
U.S. this would lead to a decrease of 2.5% of the admissions in surgical APR-DRGs.
We have found a decrease of 1.2% in the surgical APR-DRGs in our dataset. The
decrease in surgical admissions amounts to 0.7% for in-patients.
Contrary to v15, secondary diagnoses that relate to “complications of care” do not
contribute to the assignment of the Severity of Illness (SoI) or Risk of Mortality (RoM)
subclasses in v28 unless they are specified as being Present on Admission (POA). This
specification has been included with the revision of the Belgian Minimal Clinical
Dataset to the Minimal Hospital Dataset in 2008. The quality of this new parameter
however has been insufficient until now with 0 to 100% of the diagnoses coded as
Present On Admission in some institutions. Feedback must and will be given to the
hospitals and focused audits carried out to increase registration accuracy of this
parameter.
The determination of SoI and RoM for the APR-DRG system has been revised as a
consequence of the transition. The principle of 3 phases and 18 steps in the routing
algorithm remains unchanged but within several steps, significant changes have been
made. All secondary diagnoses are assigned to a certain “standard SoI level” in step 2.
The SoI and RoM level has decreased for a considerable number of admissions
compared with v15. In step 6 of the algorithm, the standard SoI level is increased when
certain non Operating Room procedures are performed. This step has become less
important in v28: a shorter list of non Operating Room procedures is taken into account
with a shift to lower SoI and RoM levels as a consequence on the global output. The
number of admissions in the (minor) SoI class 1 increases with 5.6% from v15 to v28
in our dataset.
The final result of the revision process from v15 to v28 was the creation of 1.258
different stay groups for v28 (APR-DRG and SoI combined), compared to more than
1.400 groups in v15. In the Belgian 2009-1 dataset, 1.383 stay groups are present in the
v15 system. This number has been reduced to 1230 groups for the 28.0 version, a
decrease of 11%. Further calculation and comparison of both systems can be done
regarding the length of stay, by means of the R2 (ANOVA, % of explained variation).
Other cost variables such as medication are also of further interest.
2.2. Observations
Versions 15.0 and 28.0 have algorithms that differ in many ways. The impact on
the grouping of the Belgian hospital stays will not be negligible.
In all, 30.86% of the stays will be assigned a different APR-DRG and SoI in v28
compared to v15. These hospitals stays will now face comparison to another “peer
group”. This migration will have a profound impact on the characteristics of both the
APR-DRGs of “outflow” and “inflow”. The 69.14% of stays which remain in the same
DRG will equally be compared to a changed peer group
Table 1. Allocation to APR-DRGs or SoI according to the v15 and v28 of the 3MTM APR-DRG
different SOI
same SOI
Total
different DRG
2.51%
14.79%
17.30%
same DRG
13.56%
69.14%
82.70%
Total
16.07%
83.93%
.
Figure 1.Changes in Severity of Illness per DRG
Some APR-DRGs show significant changes in the Severity of Index between v15
and v28 e.g. APR-DRG 180 “Other circulatory system procedures” has an increase
from 25% to 97% in SoI 1 hospital stays between both versions as shown in figure 1.
Another 39 APR-DRGs have an increase of more than 20% of the total number of stays
in SoI 1.
In- and outflow between different APR-DRGs was the next phenomenon studied.
Figure 2 shows the fraction of hospital stays that remains within the same APR-DRG
through conversion from v15 to 28.0. Out of 357 DRGs, 122 have an outflow of more
than 20% of their hospital stays. These 122 DRGs represent 418.342 hospital stays out
of a total of 1.760.840 (23.76%).
Figure 2. Outflow to same APR-DRG.
Fraction per APR-DRG v15 which arrives in the
same APR-DRG between v15 and v28
Figure 3. Inflow to same APR-DRG.
Fraction per APR-DRG v28 which comes
from the same APR-DRG between v15 and
v28
Figure 3 shows the fraction of hospital stays in the APR-DRGs v28 that originates
from the same APR-DRG in v15. A total number 235 APR-DRGs out of 317 have a
fraction of 80% or more admissions that remain within the same DRG. The remaining
82 APR-DRGs have a fraction of more than 0.2 “newcomers”. These 82 APR-DRGs
represent 25.38% of all hospital stays in our dataset.
Combining these 4 criteria (DRG, SoI in- and outflow) we observe that 906,559
(51.48%) of hospital stays in the Belgium dataset of the first semester 2009 either find
themselves in a different DRG or SoI, or remain in the same APR-DRG but the DRG
itself has changed considerably. This will have a significant impact on the financing of
hospitals, which is case-mix based in Belgium.
3. Discussion
The necessary upgrade from 3MTM APR-DRG v15 to v28 (or higher) will have a
larger impact on the measurement of hospital activity in Belgium than the transition of
ICD-9-CM towards ICD-10-CM/PCS itself. The majority of hospital stays will be
influenced by the DRG upgrade. On the other side, the APR-DRG will initially be
“ICD neutral” since the ICD-9-CM or ICD-10-CM/PCS coding systems will lead to
identical DRGs. It will not be until later versions that more medical information will
lead to a different DRG assignment through ICD-10-CM/PCS coding..
The consequences will be obvious in many more areas of the complex Belgian
Hospital financing system (average length of stay financing based on APR-DRG; SOI
and age), medication, medical imagery, clinical biology, medical activity, etc. More
than half of Federal hospital funding will be influenced by this update and as will
numerous quality programs.
References
[1] Richard F. Averill, All Patient Refined Diagnosis Related Groups (APR-DRGs) v15Definitions Manual,
3M Health Information Systems, 1998
[2] Richard F. Averill, 3MTMAPR DRG Classification System v15 Definitions Manual, 3M Health
Information Systems, 2010