Quality of diagnostic coding and information flow from hospital to general practice

To describe the transfer of patient information from hospital to general practice and compare the quality of coding of patient diagnoses in hospital and general practice systems.

Wellington Hospital and patients registered with 12 general practitioners (GPs) from two local computerised general practices. Discharge and outpatient letters for the period June to August 2003 were analysed and diagnostic coding compared between letters and electronic health records (EHR) in hospital and general practice. A questionnaire was sent to 167 consultants and 112 GPs from Wellington city region with a 71% response rate.

GPs received 55% of 284 discharge letters and 97% of 612 outpatient letters with a mean time of 9.4 days (range 0-70 days) and 14 days (range 0-120 days). The mean number of diagnostic codes recorded in discharge letters was 2.9 per letter, in the GPs' EHR 0.9 per letter, and in the hospital EHR 3.5 per letter. GPs were sent new diagnostic information in 30% of discharge and 36% of outpatient letters. There was more coding agreement between GPs' EHR and discharge letters than between the hospital EHR and discharge letters (65% versus 35%). GPs duplicated coding for 71% of all letters, and 74% of diagnoses were coded within the classification section of the GPs' EHR. More GPs than hospital doctors coded patient diagnoses (85% versus 15%), had any formal training in coding (25% versus 2%), and thought coding improved patient care (75% versus 50%). Most doctors in both groups experienced considerable delay of information flow and favoured an electronic transfer of information.

There is delay in information flow from hospital to general practice and poor comparison of diagnostic coding across the two systems. Attitudinal differences and inefficient coding practices will need to be addressed to produce an integrated information system between hospital and general practice.