Value-based healthcare in ischemic stroke care: case-mix adjustment models for clinical and patient-reported outcomes

Arvind Oemrawsingh,Hester F Lingsma,Carla H Bakker,Aafke J De Groot,Esmee Venema,Martien Limburg,Jan A Hazelzet,Diederik W J Dippel,Pieter H E Hilkens,Nikki Van Leeuwen,Markus P Wijffels,Frank-Erik De Leeuw,Helene R Voogdt-Pruis

doi:10.1186/s12874-019-0864-z

Abstract

BackgroundPatient-Reported Outcome Measures (PROMs) have been proposed for benchmarking health care quality across hospitals, which requires extensive case-mix adjustment. The current study’s aim was to develop and compare case-mix models for mortality, a functional outcome, and a patient-reported outcome measure (PROM) in ischemic stroke care.MethodsData from ischemic stroke patients, admitted to four stroke centers in the Netherlands between 2014 and 2016 with available outcome information (N = 1022), was analyzed. Case-mix adjustment models were developed for mortality, modified Rankin Scale (mRS) scores and EQ-5D index scores with respectively binary logistic, proportional odds and linear regression models with stepwise backward selection. Predictive ability of these models was determined with R-squared (R2) and area-under-the-receiver-operating-characteristic-curve (AUC) statistics.ResultsAge, NIHSS score on admission, and heart failure were the only common predictors across all three case-mix adjustment models. Specific predictors for the EQ-5D index score were sex (β = 0.041), socio-economic status (β = − 0.019) and nationality (β = − 0.074). R2-values for the regression models for mortality (5 predictors), mRS score (9 predictors) and EQ-5D utility score (12 predictors), were respectively R2 = 0.44, R2 = 0.42 and R2 = 0.37.ConclusionsThe set of case-mix adjustment variables for the EQ-5D at three months differed considerably from the set for clinical outcomes in stroke care. The case-mix adjustment variables that were specific to this PROM were sex, socio-economic status and nationality. These variables should be considered in future attempts to risk-adjust for PROMs during benchmarking of hospitals.

Highlights

Patient-Reported Outcome Measures (PROMs) have been proposed for benchmarking health care quality across hospitals, which requires extensive case-mix adjustment
An important limitation of this study is the notably large amount of missing outcome data in the original database. This problem is not uncommon in registries that are routinely acquired for the purpose of quality of care assessment, and it was the main reason this study solely focused on the development of case-mix risk adjustment models rather than benchmarking the included stroke centers
In conclusion, this study shows that other predictors should be considered as potential case-mix variables for patient-reported outcome measures (PROMs) than for clinical outcomes in ischemic stroke patients

Summary

Introduction

Patient-Reported Outcome Measures (PROMs) have been proposed for benchmarking health care quality across hospitals, which requires extensive case-mix adjustment. The current study’s aim was to develop and compare case-mix models for mortality, a functional outcome, and a patient-reported outcome measure (PROM) in ischemic stroke care. An important consideration for meaningful comparisons across hospitals is the case-mix adjustment of the patient populations for each health care provider [9, 10]. There has been considerable research conducted on prognostic models for these clinical outcomes, which encompass variables for case-mix adjustment [11]. There is a strong trend to use PROMs for benchmarking purposes [12], there still remains a lack of case-mix models to predict patient-reported outcomes as compared to clinical outcomes [11]. The aim of this study was to identify the specific variables for case-mix adjustment for a generic PROM (EQ-5D) and compare them to case-mix variables for clinical outcomes in acute ischemic stroke

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