Background: Patients with multiple chronic conditions are at high risk of potentially avoidable hospital admissions, which may be reduced by care coordination and self-management support. Medical assistants are an increasingly available resource for patient care in primary care practices.

Objective: To determine whether protocol-based care management delivered by medical assistants improves patient care in patients at high risk of future hospitalization in primary care.

Design: Two-year cluster randomized clinical trial.

Setting: 115 primary care practices in Germany.

Patients: 2,076 patients with type 2 diabetes, chronic obstructive pulmonary disease, or chronic heart failure and a likelihood of hospitalization in the upper quartile of the population, as predicted by insurance data analysis.

Intervention: We compared protocol-based care management including structured assessment, action planning, and monitoring delivered by medical assistants with usual care.

Measurements: All-cause hospitalizations at 12 months (primary outcome) and quality of life scores (Short Form 12 Health Questionnaire [SF-12] and the Euroqol instrument [EQ-5D]).

Results: Included patients had, on average, four co-occurring chronic conditions. All-cause hospitalizations did not differ between the groups at 12 months (risk ratio [RR] 1.01, 95% confidence interval [CI] 0.87 to 1.18) and 24 months (RR 0.98, CI 0.85 to 1.12) of intervention. Quality of life (SF-12 physical +1.16, CI 0.24 to 2.08; SF-12 mental +1.68, CI 0.60 to 2.77) and general health scores (EQ-5D +0.03, CI 0.00 to 0.05) improved significantly at 24 months of intervention. Intervention costs summed up to 10 United States dollars per patient per month.

Limitations: Limitations included a small number of primary care practices and a low intensity of intervention.

Conclusion: This type of low intensive intervention did not reduce all-cause hospital admissions. But the intervention showed positive effects on quality of life in high-risk multimorbid patients at reasonable costs.