Global health care use by patients with type-2 diabetes: Does the type of comorbidity matter?

AIM: To identify patterns of health care use among diabetic patients with multimorbidity across primary, specialised, hospital and emergency care, depending on their type of chronic comorbidity. METHODS: Longitudinal study of a population-based retrospective cohort conformed by adult patients with type-2 diabetes assigned to any of the primary care centres in Aragon during 2010 and 2011 (n=65,716). Negative binomial regressions were run to model the effect of the type of comorbidity on the number of visits to each level of care. Comorbidities were classified as concordant, discordant or mental based on expert consensus and depending on whether they shared the same overall pathophysiologic risk profile and disease management plan designed for type-2 diabetes. RESULTS: Mental comorbidity was independently associated with total and unplanned admissions (incidence rate ratio [IRR]:1.25; 95% confidence interval [CI]:1.12-1.39, IRR:1.21; 95% CI:1.06-1.39), average length of stay (IRR:1.47; 95% CI:1.25-1.73), and total and priority emergency room visits (IRR:1.26; 95% CI:1.17-1.35, IRR:1.30; 95% CI:1.18-1.42). Patients with discordant comorbidities showed the strongest associations with the number of visits to specialists (IRR:1.38; 95% CI:1.33-1.43) and to different specialties (IRR:1.36; 95% CI:1.32-1.39). Differences regarding GP visits were lower but still significant for patients with discordant comorbidity (IRR:1.08; 95% CI:1.06-1.11), but especially for those with mental comorbidity (IRR:1.17; 95% CI:1.14-1.21). CONCLUSION: In patients with type-2 diabetes, the coexistence of mental comorbidity significantly increases the use of unplanned hospital services, and discordant comorbidities have an important effect on specialised care use. Differences with respect to primary care use are not as prominent.