Table 1 Categories of unusable and insufficiently specified ICD-10 codes

Category 1: “Symptoms, signs and ill-defined conditions as the cause of death” mostly drawn from the ICD-10 Chapter XVIII codes or R codes.

Category 2: “Impossible as underlying causes of death” including conditions such as essential hypertension and atherosclerosis as well as causes which are the long-term sequelae of various diseases.

Category 3: “Intermediate causes of death” being diseases or injuries that have been precipitated by an underlying cause (e.g. heart failure).

Category 4: “Immediate causes of death” such as cardiac arrest or respiratory failure.

Category 5: “Insufficiently specified causes of death within ICD Chapters” partially informative causes such as causes within a larger cause of death category, e.g. malignant neoplasm without specification of site, or unspecified vehicle accidents.