Sixteen years of ICPC use in Norwegian primary care: looking through the facts

Abstract

Background: The International Classification for Primary Care (ICPC) standard aims to facilitate simultaneous and longitudinal comparisons of clinical primary care practice within and across country borders; it is also used for administrative purposes. This study evaluates the use of the original ICPC-1 and the more complete ICPC-2 Norwegian versions in electronic patient records.

Methods: We performed a retrospective study of approximately 1.5 million ICPC codes and diagnoses that were collected over a 16-year period at 12 primary care sites in Norway. In the first phase of this period (transition phase, 1992-1999) physicians were allowed to not use an ICPC code in their practice while in the second phase (regular phase, 2000-2008) the use of an ICPC code was mandatory. The ICPC codes and diagnoses defined a problem event for each patient in the PROblem-oriented electronic MEDical record (PROMED). The main outcome measure of our analysis was the percentage of problem events in PROMEDs with inappropriate (or missing) ICPC codes and of diagnoses that did not map the latest ICPC-2 classification. Specific problem areas (pneumonia, anaemia, tonsillitis and diabetes) were examined in the same context.

Results: Codes were missing in 6.2% of the problem events; incorrect codes were observed in 4.0% of the problem events and text mismatch between the diagnoses and the expected ICPC-2 diagnoses text in 53.8% of the problem events. Missing codes were observed only during the transition phase while incorrect and inappropriate codes were used all over the 16-year period. The physicians created diagnoses that did not exist in ICPC. These 'new' diagnoses were used with varying frequency; many of them were used only once. Inappropriate ICPC-2 codes were also observed in the selected problem areas and for both phases.

Conclusions: Our results strongly suggest that physicians did not adhere to the ICPC standard due to its incompleteness, i.e. lack of many clinically important diagnoses. This indicates that ICPC is inappropriate for the classification of problem events and the clinical practice in primary care.

Figure 1

The tree structure of PROMED with '1 to n' problem histories. Each box represents one database record for a problem event. Problem 1 has two events; problem 2 has 5 events, etc. The history of each problem starts with a black box and ends with a red; the blue are intermediate events.

Figure 2

Diagnoses and narratives for a patient with two problems. The problem 'septicaemia' (i.e. 'Sepsis IKA') is highlighted in blue (upper left list). The history of the problem events before 'septicaemia' is shown in the upper right list. All narratives for 'septicaemia' problem are shown in the text field with the grey background. The lowermost field with the white background contains the narrative ('XXXXXXXXXXXX') to be added. An ICPC diagnosis/code is reused if the physician selects a diagnosis from the upper left list and presses the button 'SAVE AS SAME PROBLEM'. Otherwise a new diagnosis-code is selected from the ICPC diagnosis-code register through the 'NYTT PROBLEM' (translation: 'NEW PROBLEM') menu. The icons above the two lists give access to other modules and automatically change the menu options

Figure 3

User interface of the ICPC diagnosis-code module. Users may select a category from the right list and then the corresponding ICPC-2 diagnosis from the left list. Alternatively, the diagnoses may be selected using substring search in the 'DIAGNOSENAVN' (translation: 'DIAGNOSIS NAME') field. In both cases, the selected ICPC-2 code and diagnosis are automatically assigned to global memory variables and are used in all the PROMED modules. For example, the diagnosis acute cystitis (i.e. 'Cystitt akutt') is selected (highlighted blue) and is automatically copied to the 'DIAGNOSENAVN' field; the corresponding ICPC-2 code is automatically copied to the 'KODE'(translation: 'CODE') field.

Figure 4

The percentage of problem events with missing codes, code mismatch and diagnosis text mismatch over the total number of problem events per year.