Development and evaluation of a national administrative code-based system for estimation of hospital-acquired venous thromboembolism in Ireland.

BACKGROUND

Hospital-acquired venous thromboembolism (HA-VTE) is a significant patient safety concern contributing to preventable deaths. Internationally, estimating HA-VTE relies on administrative codes, in particular the International Classification of Disease (ICD) codes, but their accuracy has been debated. The Irish Health Service Executive (HSE) launched a National Key Performance Indicator (KPI) in 2019 for monitoring HA-VTE rates using the Australian Modification of ICD-10 (ICD-10-AM) codes.

OBJECTIVES

This study aims to (1) describe the development of the national HSE KPI and determine the national HA-VTE occurrence rate per 1000 discharges in 2022; (2) assess the contribution of each VTE ICD-10-AM code to the national HA-VTE figure; (3) estimate the positive predictive value (PPV) of the HSE KPI against true HA-VTE, in a single large tertiary (Irish Model 4) hospital.

METHODS

A retrospective observational study used national data from Irish publicly funded acute hospitals, focusing on discharges from 2022. The HSE KPI was based on an assessment of HA-VTE as a rate per 1000 hospital discharges (as per the national metadata). Inclusion criteria were inpatient only, length of stay ≥2 days, age ≥16 years and non-maternity admission type (elective or emergency only). Maternity and paediatric hospitals were excluded.The PPV was determined through a detailed review of HA-VTE cases identified through the HSE KPI from April 2020 to October 2022 in a single large tertiary referral centre and determining the proportion indicating a true HA-VTE. Data analysis employed GraphPad Prism (Horsham, PA, USA).

RESULTS

The national mean monthly HA-VTE rate was 11.38 per 1000 discharges in 2022. Pulmonary embolism (PE) without acute cor pulmonale (I26.9) was the most frequent contributor (59%). The mean PPV in the tertiary hospital was 0.37, with false positives attributed to acute illnesses, historical VTE coding errors and dual VTE diagnoses at admission.

DISCUSSION

HA-VTE is a preventable cause of morbidity and mortality, necessitating accurate measurement. Administrative codes, while cost-effective and timely, reveal limitations in precision. This study identifies opportunities to improve code accuracy, address coding challenges and enhance the PPV.

CONCLUSION

This study provides valuable insights into estimated HA-VTE rates, the contribution of each individual ICD-10-AM code to the overall HA-VTE rate and the PPV of the measure. Ongoing refinement and quality enhancement are needed.