The Interplay Between Continuity of Care, Multimorbidity, and Adverse Events in Patients With Diabetes

Objectives: To evaluate the impact of continuity of care and multimorbidity on health outcomes in patients with diabetes. Research Design: Using a US claims database of insured patients, we identified those with incident diabetes between 2004 and 2008 and followed them until death, disenrollment, or December 31, 2010. Continuity of care was defined using Breslau's Usual Provider of Continuity (UPC; proportion of visits to the usual or predominant provider within 2 y of diabetes diagnosis). Multivariable logistic regression was used to determine the association between UPC in the first 2 years after diabetes diagnosis and subsequent 1-year composite primary outcome of all-cause hospitalization or death in year 3 in patients with/without multimorbidity. Results: Of the 285,231 patients with incident diabetes, 74% had multimorbidity; their average age was 53 years (SD=10.5) and 49% were female. A total of 77,270 (27%) individuals had a mean UPC >= 75% in the first 2 years. During year 3 of follow-up, 33,632 (12%) patients died or were hospitalized for any cause. Greater continuity of care (UPC >= 75%) was associated with reduced risk of subsequent death or hospitalization [7.2% vs. 13.5%; adjusted odds ratio (aOR)=0.72; 95% CI, 0.70-0.75]. Although multimorbidity was independently associated with an increased risk of our primary composite endpoint (13.4% vs. 7.2%; aOR=1.26; 95% CI, 1.21-1.30), the association between greater continuity and better outcomes was similar in those with multimorbidity (aOR=0.71; 95% CI, 0.69-0.71) as in those without (aOR=0.75; 95% CI, 0.71-0.80). Conclusions: In patients with incident diabetes, greater continuity of care is associated with improved outcomes, irrespective of whether or not they have multimorbidity.