BACKGROUND: We estimated the prevalence and the associated burden of illness of symptoms of diabetic peripheral neuropathy (SDPN), diabetic retinopathy (DR), and comorbid SDPN and DR among people with diabetes in the United States aged > or =40 years. METHODS: Analyses were conducted on 850 respondents aged > or =40 years with diagnosed diabetes from the combined 1999-2000 and 2001-2002 National Health and Nutrition Examination Surveys. Sampling weights were used to estimate the number of people with diabetes who have SDPN, DR, or comorbid SDPN and DR. Multivariate regression models were used to assess the effects of SDPN, DR, and comorbid SDPN and DR on burden-of-illness measures. RESULTS: Approximately 11.9 million adults in the United States aged > or =40 years have diagnosed diabetes. Of those, 3.9 million (32.7%) have SDPN, 3.3 million (27.4%) have DR, and 1.6 million (13.1%) have comorbid SDPN and DR. Among our sample, those with SDPN [odds ratio (OR)=2.25; 95% confidence interval (95% CI)=1.32-3.83], DR (OR=1.68; 95% CI=1.08-2.61), or comorbid SDPN and DR (OR=2.84; 95% CI=1.26-6.41) were more likely than those without the corresponding condition to have four or more health care visits in the past year. Those of working age (40-65 years) with SDPN (OR=3.23; 95% CI=1.60-6.52), DR (OR=2.94; 95% CI=1.45-5.97), or comorbid SDPN and DR (OR=4.32; 95% CI=2.17-8.63) were more likely unable to work due to physical limitations. CONCLUSIONS: SDPN, DR, and comorbid SDPN and DR are prevalent among people with diabetes in the United States aged > or =40 years; each of these complications appears to significantly increase the burden of illness
