Journal of clinical oncology : official journal of the American Society of Clinical Oncology | 16 Feb 2017
RS Go, AC Bartley, CS Crowson, ND Shah, EB Habermann, SJ Holton and DR Holmes
Purpose To determine the association between the number of patients with multiple myeloma (MM) treated annually at a treatment facility (volume) and all-cause mortality (outcome). Methods Using the National Cancer Database, we identified patients diagnosed with MM between 2003 and 2011. We classified the facilities by quartiles (Q; mean patients with MM treated per year): Q1: < 3.6; Q2: 3.6 to 6.1, Q3: 6.1 to 10.3, and Q4: > 10.3. We used random intercepts to account for clustering of patients within facilities and Cox regression to determine the volume-outcome relationship, adjusting for demographic (sex, age, race, ethnicity), socioeconomic (income, education, insurance type), geographic (area of residence, treatment facility location, travel distance), and comorbid (Charlson-Deyo score) factors and year of diagnosis. Results There were 94,722 patients with MM treated at 1,333 facilities. The median age at diagnosis was 67 years, and 54.7% were men. The median annual facility volume was 6.1 patients per year (range, 0.2 to 109.9). The distribution of patients according to facility volume was: Q1: 5.2%, Q2: 12.6%, Q3: 21.9%, and Q4: 60.3%. The unadjusted median overall survival by facility volume was: Q1: 26.9 months, Q2: 29.1 months, Q3: 31.9 months, and Q4: 49.1 months ( P < .001). Multivariable analysis showed that facility volume was independently associated with all-cause mortality. Compared with patients treated at Q4 facilities, patients treated at lower-quartile facilities had a higher risk of death (Q3 hazard ratio [HR], 1.12 [95% CI, 1.08 to 1.16]; Q2 HR, 1.17 [95% CI, 1.12 to 1.21]; Q1 HR, 1.22 [95% CI, 1.17 to 1.28]). Conclusion Patients who were treated for MM at higher-volume facilities had a lower risk of mortality compared with those who were treated at lower-volume facilities.
* Data courtesy of Altmetric.com