Merging the Swedish outpatient DRGs M32P & M32Q for dialysis
|Target version:||NordDRG 2021|
|Case type:||Major||Owner / responsible:||National organisations|
|MDC:||MDC11||Old forum status:|
Mats Fernström, the National Board of Health and Welfare, Sweden, 2020-02-19. Swe ID C757.
This case applies only to the Swedish version of NordDRG but is published for information and perhaps some education. By reading the italicized text below you can learn from our mistakes.
For several years, the average cost for DRG M32Q (Admit for renal dialysis, short therapy) has been greater than ditto for DRG M32P (Admit for renal dialysis, short therapy). As this has been repeated year after year, it cannot be due to a coincidence.
We noticed that one of the rules for DRG M32P (complex) did not work as intended. It is based on the demand of 11S09 (Dialysis) in the field “proc1” and 11S25 (Major supporting procedure for dialysis) in the field “secproc”. When the rule was constructed, several years ago, we gave the property 11S25 in addition to the existing property 11S09 to a number of procedure codes for dialysis that we judged to be more expensive dialysis. What we didn’t think of, was that the demands in the fields “proc1” and “secproc” cannot be fulfilled by a single procedure code. There must be one code that fulfills the demand in the field “proc1” and another code that fulfills the demand in the field “secproc”. This is hardcoded in the grouper. That means that you must register the dialysis twice with two different codes and that is probably not done in the hospitals. Besides, it shouldn’t be necessary.
So we tried to change the grouping logic in the way that the property 11S25 was replaced by a diagnosis property (11X10) with the same meaning as 11S25 and in the rule for DRG M32P, 11S25 in the field “secproc” was deleted and 11X10 was inserted in the field “dgprop1”. Now the rule was functioning. Instead of 14 posts we got around 1 500 posts grouped according that rule. But unfortunately, the average cost for DRG M32Q (noncomplex) was still greater than ditto for DRG M32P (complex)!
The inevitable question then was if we, several years ago, had misjudged which dialysis procedures that are more expensive. Therefore we now looked at the average costs for cases with the different procedure codes within the entire group of cases with dialysis and we noticed that several of the codes with 11S25 indicated a cost lower than the average for the entire group and vice versa, several of the codes without 11S25 indicated a cost higher than the average for the entire group. These findings were contradictory also to our current medical assessment so we asked an expert on the KPP (Cost per patient) database at the Swedish Association of Local Authorities and Regions and he said that the cost calculation methods for outpatient cases with dialysis are not so precise that they take into account that different methods for dialysis are different costly.
With this information we realize that it is pointless to keep the splitting into “complex” and “noncomplex” for the DRG for outpatient dialysis.
Thus, we have decided to merge DRG M32P and DRG M32Q to DRG M32O ‘Admit for renal dialysis, short therapy’/‘Dialysbehandling, öppenvård’. This is achieved by deletion of all rules leading to DRG M32P in the table DRGLOGIC and in the rules for DRG M32Q the DRG is changed to M32O. Then the property 11S25 is no longer needed so all rows with that property in the tables DG, PROC and PROC_PROP can be deleted. In the table DRGNAMES, DRG M32P and DRG M32Q will be replaced by DRG M32O. A spinoff effect will be that there are no longer any diagnosis code with a procedure property. Detailed technical changes are in the file TC_C757.xlsx.
The DRG change will be that all cases that used to be grouped to DRG M32P or DRG M32Q instead will be grouped to DRG M32O.