Reporting of diabetes on death certificates using data from the UK Prospective Diabetes Study

Aims To study the effect of age at death, sex, ethnic group, date of death, underlying cause of death and social class on the frequency of reporting diabetes on death certificates in known cases of diabetes. Methods Data were extracted from certificates recording 981 deaths which occurred between 1985 and 1999 in people aged 45 years or more who participated in the UK Prospective Diabetes Study, to which 23 English, Scottish and Northern Ireland centres contributed. Diabetes (9th revision of the International Classification of Diseases; ICD-9 250) entered on parts 1A-1C or 2A-2C of the death certificate was considered as reporting diabetes. Logistic regression analyses were used to determine independent factors associated with the reporting of diabetes. Results Diabetes was reported on 42% (419/981) of all death certificates and on 46% (249/546) of those with underlying cardiovascular disease causes. Reporting of diabetes was independently associated on all death certificates with per year of age increase (OR 1.02; 95% CI 1.001-1.04, P = 0.037), underlying cause of death (non-cardiovascular causes OR 0.76; 95% CI 0.59-0.98, P = 0.035) and social class (classes I-II OR 1.00; class III OR 1.35; 95% CI 0.96-1.89, P = 0.084, classes IV-V OR 1.48; 95% CI 1.05-2.10, P = 0.027). Stratification by age, sex, and underlying cause of death also revealed significant differences in the frequency of reporting diabetes over time. Conclusions The rate of reporting of diabetes on cardiovascular disease death certificates remains poor. This may indicate a lack of awareness of the importance of diabetes as a risk factor for cardiovascular disease.