The Effect of Continuity of Care on Emergency Room Use for Diabetic Patients Varies by Disease Severity

BACKGROUND Although many studies have reported that high-quality continuity of care (COC) is associated with improved patient outcomes for patients with diabetes, few studies have investigated whether this positive effect of COC depends on the level of diabetes severity. METHODS A total of 3781 newly diagnosed diabetic patients selected from the 2005 National Health Insurance database were evaluated for the period 2005-2011. Generalized estimating equations combined with negative binomial estimation were used to determine the influence of COC on the overall emergency room (ER) use and diabetes mellitus (DM)-specific ER use. Analyses were stratified according to diabetes severity (measured using the Diabetes Complications Severity Index [DCSI]), comorbidities (measured using the Charlson comorbidity score), and age. RESULTS COC effects varied according to diabetes severity. Stratified analysis showed that the positive effect of COC on DM-specific ER use was the highest for a DCSI of 0 (least severe), with an incidence rate ratio (IRR) of 0.49 (95% CI, 0.41-0.59) in the high-COC group (reference group: low-COC group). Compared with the low-COC group, high-quality COC had a significant beneficial effect on overall ER use in younger patients (IRR 0.51; 95% CI, 0.39-0.66 for the youngest [18-40 years] group, and IRR 0.67; 95% CI, 0.59-0.76 for the oldest [>65 years] group) and those with a high number of comorbidities. CONCLUSIONS The positive effects of high-quality COC on the treatment outcomes of patient with diabetes, based on the overall and DM-specific ER use, depends on the level of disease severity. Therefore, providing health education to enhance high-quality COC when the disease severity is low may be critical for ensuring optimal positive effects during diabetes disease progression.