Ill-defined and multiple causes on death certificates--a study of misclassification in mortality statistics

Area of Science:

• Epidemiology
• Public Health
• Medical Statistics

Background:

• Mortality data is a crucial epidemiological resource, but biases can distort its value.
• Accurate cause-of-death assignment is essential for reliable public health surveillance.
• Previous studies highlight potential issues with coding ill-defined and multiple causes.

Purpose of the Study:

• To assess the extent of misclassification in underlying cause of death assignments.
• To identify shortcomings in the International Classification of Diseases, Ninth Revision (ICD-IX) for ill-defined and multiple causes.
• To investigate the impact of physician interviews and clinical records on improving cause-of-death accuracy.

Main Methods:

• A random sample of 372 death certificates from Naples, Italy (1994) reporting ill-defined or multiple causes was analyzed.
• The initially assigned ICD-IX code for the underlying cause was compared with a modified code.
• The modified code was determined through interviews with certifying physicians or review of clinical records.

Main Results:

• Ill-defined causes accounted for 7.0% of death certificates, including cardiovascular diseases, unspecified tumors, and senility.
• Significant disagreement (53.8%) was found between assigned and modified codes for ill-defined causes, particularly when certified by family physicians.
• Multiple causes were present in 23.6% of certificates, with disagreement in 54.5% of these cases; concurrence of causes was noted in 10 instances.

Conclusions:

• Specific training for physicians on certification procedures alone is insufficient; awareness of data's epidemiological importance is needed.
• Evidence-based educational interventions are necessary to improve the quality of mortality data.
• Multicausal analysis may be indicated for deaths resulting from a concurrence of causes to enhance accuracy.