[Coding of diagnoses in chronic obstructive pulmonary disease--economic consequences]

We wanted to assess the quality of coding of diagnoses and procedures, the resulting DRG classification and the financial consequences of coding errors for the hospital owner in patients with chronic obstructive pulmonary disease.

We identified 330 hospitalizations in the Central Hospital of Akershus 1 January to 30 November 1999 in DRG 088 (chronic obstructive pulmonary diseases) after an initial DRG classification. The patients' discharge summaries were reviewed for errors in coding of diagnoses and procedures and, where applicable, recoded. DRG classification was then redone and the changes analysed.

After review of 302 available discharge summaries (92%) and recoding, the most common primary diagnoses were chronic obstructive pulmonary disease (68%), respiratory failure (17%), and pneumonia (8%). The recoding led to change of the primary diagnosis in 16% of the patient stays, additional secondary diagnosis (18%) or both (18%). The coding was changed for 175 (58%) patients, of which 94 recodings (31%) led to changes in the resulting DRG. On average, the recoding led to an increase per hospitalization of 0.30 DRG points. Two of five coders frequently used respiratory failure as the primary diagnosis (37-43% for hospitalization).

The initial routine coding was incomplete. There was large variation in recoding between medically qualified coders; this may have considerable financial consequences for a hospital. There were several problems related to the interpretation of ICD-10 coding, creating opportunities for "upcoding".