Abstract
Higher amenable mortality and lower rates of healthcare utilisation have recently been identified for Aotearoa New Zealand’s (NZ’s) rural and rural Māori populations. These findings rely upon clinical information coded within routinely collected administrative datasets. Anecdotally, clinical coding is often performed by clinicians or reception staff without formal coding training in many NZ rural hospitals. The agreement of clinical coding between NZ rural and urban hospitals is unknown, and data from comparable international health systems is scarce, dated, or inconclusive. This retrospective observational study examined whether discrepancies existed between the clinical diagnosis codes assigned in the National Minimum Dataset (NMDS) for patients who underwent an inter-hospital transfer from a rural to an urban hospital.
NZ hospitals were classified into ‘Rural hospitals’, ‘Small urban centre hospitals’, and ‘Large urban centre hospitals’ based on Geographical Classification for Health categories R1-3, U2, and U1 respectively. Clinical diagnosis codes were collected from the NMDS and assigned corresponding diagnosis groups like ‘Infection’. The number and percentage, with 95% confidence intervals, of encounters where the primary diagnosis codes from the rural and urban hospitals were discordant were calculated.
Included were 31,691 patients from 54 NZ publicly funded hospitals who underwent an inter-hospital transfer from a rural to an urban hospital between 1st January 2015, and 31st December 2019. Discrepancies existed in 64.1% (20,303/31,691, 95% CI 63.5% - 64.6%) of the clinical codes assigned between the rural and urban hospitals, and in 32.1% (10,168/31,691, 95% CI 31.6% - 32.6%) of broader diagnosis groups. Discrepancies were slightly higher for transfers to small urban centre hospitals compared to large urban centre hospitals. Differences in coding practices or rural hospital shortages of resources, diagnostic investigations, and staff with formal coding training are possible explanations. Further investigation with clinical note review is needed to determine the source of these discrepancies.