Patients with multiple myeloma who received care at higher-volume treatment facilities had a lower risk of death compared with those treated at lower-volume facilities, according to a study published in the Journal of Clinical Oncology.1
To evaluate the association between the number of patients with multiple myeloma treated annually at a treatment facility and all-cause mortality, researchers at the Mayo Clinic in Rochester, MN, analyzed data from 94,722 patients with multiple myeloma diagnosed between 2003 and 2011 who were treated at any 1 of 1333 facilities. Median age was 67 years and nearly 55% were men.
Facilities were classified by quartiles, with quartile 1 treating an average of fewer than 3.6 patients with multiple myeloma per year, quartile 2 treating between 3.6 and 6.1 per year, quartile 3 treating 6.1 to 10.3 per year, and quartile 4 treating more than an average of 10.3 patients annually. The median annual facility volume was 6.1 patients per year.
Results showed that 5.2% of patients were treated at facilities in quartile 1, 12.6% at quartile 2, 21.9% at quartile 3, and 60.3% at quartile 4. Median overall survival was 26.9 months, 29.1 months, 31.9 months, and 49.1 months at institutions classified as quartiles 1, 2, 3, and 4, respectively (P < .001).
After adjusting for confound factors, investigators found that facility volume was independently associated with all-cause mortality.
Specifically, patients treated at quartile 1 facilities had a 22% higher risk of death compared with those treated at quartile 4 facilities (hazard ratio [HR], 1.22; 95% CI, 1.17-1.28), and patients treated at quartile 2 facilities had a 17% higher risk vs those who received care at quartile 4 facilities (HR, 1.17; 95% CI, 1.12-1.21).
Patients treated at facilities classified in quartile 3 had a 12% increased risk of all-cause mortality compared with those in quartile 4 (HR, 1.12; 95% CI, 1.08-1.16).
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This study is limited by potential selection bias as it does not take into account physician referral or patient self-selection, nor does it account for the annual physician volume or cumulative physician experience.
These findings build upon the mounting evidence that facility volume correlates with outcome in the management of hematologic malignancies.