Prevalence and comorbidity of diabetes mellitus among non-institutionalized older adults in Germany - results of the national telephone health interview survey 'German Health Update (GEDA)' 2009

Background: Despite the major public health impact of diabetes, recent population-based data regarding its prevalence and comorbidity are sparse. Methods: The prevalence and comorbidity of diabetes mellitus were analyzed in a nationally representative sample (N = 9133) of the non-institutionalized German adult population aged 50 years and older. Information on physician-diagnosed diabetes and 20 other chronic health conditions was collected as part of the national telephone health interview survey 'German Health Update (GEDA)' 2009. Overall, 51.2% of contacted persons participated. Among persons with diabetes, diabetes severity was defined according to the type and number of diabetes-concordant conditions: no diabetes-concordant condition (grade 1); hypertension and/or hyperlipidemia only (grade 2); one comorbidity likely to represent diabetes-related micro-or macrovascular end-organ damage (grade 3); several such comorbidities (grade 4). Determinants of diabetes severity were analyzed by multivariable ordinal regression. Results: The 12-month prevalence of diabetes was 13.6% with no significant difference between men and women. Persons with diabetes had a significantly higher prevalence and average number of diabetes-concordant as well as diabetes-discordant comorbidities than persons without diabetes. Among persons with diabetes, 10.2%, 46.8%, 35.6% and 7.4% were classified as having severity grade 1-4, respectively. Determinants of diabetes severity included age (cumulative odds ratio 1.05, 95% confidence interval 1.03-1.07, per year) and number of discordant comorbidities (1.40, 1.25-1.55). With respect to specific discordant comorbidities, diabetes severity was correlated to depression (2.15, 1.29-3.56), respiratory disease (2.75, 1.72-4.41), musculoskeletal disease (1.53, 1.06-2.21), and severe hearing impairment (3.00, 1.21-7.41). Conclusions: Diabetes is highly prevalent in the non-institutionalized German adult population 50 years and older. Diabetes comorbidities including diabetes-concordant and diabetes-discordant conditions need to be considered in epidemiological studies, in order to monitor disease burden and quality of diabetes care. Definitional standards of diabetes severity need to be refined and consented.