Measuring continuity of care for diabetes: which visits to include?

Objectives: Continuity of care measures are widely used to evaluate the quality of health care delivery, but which visits are included vary across studies. Our objective was to determine how the provider specialties included affect continuity values, year-to-year stability, and association with emergency department (ED) visits.

Study Design: Retrospective study of Alabama Medicaid administrative data.

Methods: We included beneficiaries with diabetes who had at least 3 outpatient visits in each of 2018 and 2019 (N = 9578). We defined 3 provider groupings: all providers, diabetes-broad (primary care, cardiology, neurology, endocrinology, ophthalmology, nephrology, and psychiatry), and diabetes-narrow (primary care and endocrinology). Continuity of care was calculated using the Continuity of Care Index (COCI) for each provider grouping. We compared correlation between measures and from year to year using Spearman correlations, and we used multivariable logistic regression to determine association with ED visits.

Results: The mean COCI was 0.54 using visits with all providers, 0.64 with diabetes-broad providers, and 0.83 with diabetes-narrow providers. COCI with diabetes-narrow providers was moderately correlated with the broader sets of providers (Spearman ρ, 0.52-0.65). Comparing each participant's COCI in 2018 with that in 2019, the mean intraperson difference was similar (0.16-0.22), and correlation was moderate (Spearman ρ, 0.41-0.47) for each measure. COCI had similar weak association with ED visits using each provider grouping (odds ratio, 0.99; 95% CI, 0.98-0.99 for each 0.1-unit difference in COCI).

Conclusions: Continuity values differed substantially depending on which provider specialties were included. The importance of this variation is uncertain, as continuity was weakly associated with ED visits using each of the measures.