Relationship between multisystem multimorbidity and mean annual healthcare utilisation† among high-cost VA patients
| Number of body systems affected by chronic conditions | n | Primary care visits | Specialty care visits | Mental health visits‡ | Emergency visits | Hospital admissions |
|---|---|---|---|---|---|---|
| 1 | 30 772 | 3.1 | 3.0 | 15.4 | 1.2 | 1.0 |
| 2 | 54 837 | 4.5 | 3.7 | 14.9 | 1.6 | 1.3 |
| 3 | 66 610 | 5.6 | 4.4 | 14.5 | 1.9 | 1.5 |
| 4 | 53 937 | 6.7 | 5.2 | 14.1 | 2.3 | 1.8 |
| 5 | 30 509 | 7.8 | 5.9 | 14.6 | 2.8 | 2.0 |
| 6 | 12 566 | 9.1 | 6.7 | 14.2 | 3.4 | 2.3 |
| 7+ | 4419 | 10.5 | 7.7 | 15.1 | 4.0 | 2.6 |
| Average difference§ | 1.5* | 0.7* | −0.2 | 0.4* | 0.2* |
*p<0.01.
†Predicted annual utilisation rates are generated via multivariate zero-inflated negative binomial regression (for outpatient utilisation) and zero-inflated Poisson regression (for hospital admissions) examining associations between number of systems affected by chronic conditions and utilisation within each domain. All regressions adjust for age, sex, race/ethnicity, marital status, homelessness and insurance status.
‡Among patients with a mental health diagnosis (n=125 962), predicted mental healthcare visits decreased from 32.3 to 20.9 among patients with 1 versus ≥7 body systems affected by chronic conditions, respectively, with an average decrease in 1.9 visits per body system affected by chronic conditions (p<0.01).
§Average differences represent change in annual utilisation for each additional system affected by chronic conditions.