Continuity and the costs of care for chronic disease

Abstract

Importance: Better continuity of care is expected to improve patient outcomes and reduce health care costs, but patterns of use, costs, and clinical complications associated with the current patterns of care continuity have not been quantified.

Objective: To measure the association between care continuity, costs, and rates of hospitalizations, emergency department visits, and complications for Medicare beneficiaries with chronic disease.

Design, setting, and participants: Retrospective cohort study of insurance claims data for a 5% sample of Medicare beneficiaries experiencing a 12-month episode of care for congestive heart failure (CHF, n = 53,488), chronic obstructive pulmonary disease (COPD, n = 76,520), or type 2 diabetes mellitus (DM, n = 166,654) in 2008 and 2009.

Main outcomes and measures: Hospitalizations, emergency department visits, complications, and costs of care associated with the Bice-Boxerman continuity of care (COC) index, a measure of the outpatient COC related to conditions of interest.

Results: The mean (SD) COC index was 0.55 (0.31) for CHF, 0.60 (0.34) for COPD, and 0.50 (0.32) for DM. After multivariable adjustment, higher levels of continuity were associated with lower odds of inpatient hospitalization (odds ratios for a 0.1-unit increase in COC were 0.94 [95% CI, 0.93-0.95] for CHF, 0.95 [0.94-0.96] for COPD, and 0.95 [0.95-0.96] for DM), lower odds of emergency department visits (0.92 [0.91-0.92] for CHF, 0.93 [0.92-0.93] for COPD, and 0.94 [0.93-0.94] for DM), and lower odds of complications (odds ratio range, 0.92-0.96 across the 3 complication types and 3 conditions; all P < .001). For every 0.1-unit increase in the COC index, episode costs of care were 4.7% lower for CHF (95% CI, 4.4%-5.0%), 6.3% lower for COPD (6.0%-6.5%), and 5.1% lower for DM (5.0%-5.2%) in adjusted analyses.

Conclusions and relevance: Modest differences in care continuity for Medicare beneficiaries are associated with sizable differences in costs, use, and complications.

Figure 1

Odds of incidence of hospitalizations, emergency department visits, and complications (left) and percentage change in costs (right) associated with a 0.1 increase in the Bice-Boxerman Continuity of Care (COC) Index. Note: Medicare beneficiaries with CHF, COPD, and DM for 12-month episodes of care in 2008–09. Incidence reflects the odds ratio using logistic regression models. Cost models show the change in the COC Index change from 0.4 and 0.5. Total episode cost ratios derived from generalized linear regression models with gamma variance distribution and log link function. Cost ratios for hospitalizations, ED visits, and complications derived from two-part models with bootstrapped confidence intervals. All results are adjusted for patient age, gender, Census region, HCC, median zip code income, Medicaid enrollment, number of visits, and whether patient had visit to PCP. Error bars represent 95% confidence intervals.