Examination of Cause-of-Death Data Quality Among New York City Deaths Due to Cancer, Pneumonia, or Diabetes From 2010 to 2014.

The cause-of-death (COD) statement on the standard US death certificate is a valuable tool for public health practice, but its utility is impaired by reporting inaccuracies. To assess the quality of CODs reported in New York City, we developed and applied a quality measure to 3 leading CODs: cancer, pneumonia, and diabetes. The COD quality measure characterized 5 common issues with COD completion: nonspecific conditions as the underlying COD (UCOD); UCOD discrepancies; the presence of only 1 informative cause on the entire certificate; competing causes listed together on 1 line; and clinically improbable sequences. COD statements with more than 1 quality issue were defined as statements of "limited" quality. Of 82,116 deaths with cancer, diabetes, or pneumonia assigned as the UCOD in New York City from 2010 to 2014, 66.8% of pneumonia certificates were classified as "limited" quality as compared with 45.6% of cancer certificates and 32.3% of diabetes certificates. Forty percent of cancer certificates listed only 1 informative condition on the death certificate. Almost half of pneumonia certificates (45.9%) contained only enough information to assign International Classification of Diseases, Tenth Revision, code J18.9 ("unspecified pneumonia") as the UCOD, whereas most diabetes certificates contained UCOD discrepancies (25.2%). These limitations affect the quality of mortality data but may be reduced through quality improvement efforts.