Severity of illness and risk of mortality from all patient refined-diagnosis related groups: Two scales of different concepts or two sides of the same coin?

Autores da FMUP

• José Alberto Da Silva Freitas

  Autor

Participantes de fora da FMUP

• Santos, Joao Vasco
• Viana, Joao
• Pinto, Carla
• Souza, Julio
• Lopes, Fernando
• Lopes, Silvia

Unidades de investigação

• Laboratório Associado RISE- Rede de Investigação em Saúde

  

  Investigador

  Fernando Carlos De Landér Schmitt

• Medicina da Comunidade, Informação e Decisão em Saúde

• RISE-Health

  

  Investigador

  Fernando Carlos De Landér Schmitt

Abstract

All patient refined-diagnosis related groups (APR-DRGs) includes severity of illness (SOI) and risk of mortality (ROM) subclasses. For predictions, both subscales are used together or interchangeably. We aimed to compare SOI and ROM by evaluating the reliability and agreement between both. We performed a retrospective observational study using mainland Portuguese public hospitalisations of adult patients from 2011 to 2016. Reliability (quadratic weighted kappa) and agreement (proportion of agreement) between SOI and ROM were analysed overall and by APR-DRG. While overall reliability and agreement between SOI and ROM were high (weighted kappa: 0.717, 95% CI 0.717-0.718; proportion of agreement: 69.0%, 95% CI 69.0-69.0) there was high heterogeneity across APR-DRGs, ranging from 0.016 to 0.846 on reliability and from 23.1% to 94.8% on agreement. Most of APR-DRGs (263 out of 284) showed a higher proportion of episodes with ROM level above the SOI level than the opposite. In conclusion, SOI and Risk of Mortality measures must be clearly distinguished and are `two scales of different concepts' rather than `two sides of the same coin'. However, this is more evident for some APR-DRGs than for others. The degree of conceptual distinction between severity of illness (SOI) and risk of mortality (ROM) are specific to the diagnosis related group. SOI and ROM have high reliability and agreement overall but vary by all patient refined-diagnosis related group (APR-DRG). ROM generally scores higher than SOI in most APR-DRGs, indicating different concepts. SOI and ROM need to be differentiated for accurate outcome predictions.

Keywords

• clinical coding; diagnosis-related groups; hospital information systems; hospital mortality; prognosis; severity of illness index