2. Method changes

This chapter summarizes the changes in the HSMR method (HSMR 2023) compared to the method used last year (HSMR 2022). For previous changes see the respective methodological reports (CBS, 2011, …, 2023). Overall, the method has remained the same.

Since last year (HSMR 2022) COVID-19 admissions from 2022 onwards are included in the HSMR model using a specific COVID-19 SMR model with different definitions of covariates “Severity of the main diagnosis” and “Month of admission” (see section 3.4). This year the same COVID-19 SMR model is used as last year, but now also includes covariate “Year of discharge”, as COVID-admissions of two years (2022 and 2023) are now included. COVID-19 admissions in 2021 are still excluded. The three-year COVID-19 SMR therefore only includes COVID-19 admissions from 2022-2023.

This year only a few changes related to the indicators used for data quality and case mix have been implemented. These indicators are not used in the HSMR model, but serve as background information for the hospitals (see also section 1.6). The changes in these indicators are described below and are applied to all years of the present reporting period (2021-2023):

Indicators of palliative care:

Palliative care was previously measured with ICD-10 code Z51.5. However, this approach has limitations, see section 1.6. Therefore it is now measured using procedure codes (‘Zorgactiviteiten’) 19006, 190067 and 190173. These codes are registered when a meeting regarding palliative care or a consult by a palliative care team member has taken place during the hospital admission.

Indicator of the registration of secondary diagnoses:

In the calculation of the indicator “average number of registered secondary diagnoses per admission” supplementary diagnosis codes indicating external causes, morphology and the type of bacteria in case of an infection, are now excluded. This concerns ICD-10 codes B95-B98, U80-U85, codes starting with V, W, X or Y and morphology codes. These codes are registered supplementary to codes representing diagnoses such as injury, neoplasms and infections and do not represent a separate condition.

Indicator of the registration of complications:

In the calculation of the indicator ”percentage of registered diagnoses not present on admission (not POA)” apart from the above-mentioned supplementary diagnosis codes, Z-codes that do not indicate a condition are now also excluded. In total the following ICD-10 codes are thus excluded in this indicator: B95-B98, U80-U85, codes starting with V, W, X or Y, morphology codes, and (in the numerator only) all Z-codes except Z04.3 and Z20.