title: Association Between Treatment Facility Volume and Mortality of Patients With Multiple Myeloma.
abstract: 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.
authors.affiliation: All authors: Mayo Clinic, Rochester, MN.
authors.forename: Ronald S
authors.initials: RS
authors.lastname: Go
authors.affiliation: All authors: Mayo Clinic, Rochester, MN.
authors.forename: Adam C
authors.initials: AC
authors.lastname: Bartley
authors.affiliation: All authors: Mayo Clinic, Rochester, MN.
authors.forename: Cynthia S
authors.initials: CS
authors.lastname: Crowson
authors.affiliation: All authors: Mayo Clinic, Rochester, MN.
authors.forename: Nilay D
authors.initials: ND
authors.lastname: Shah
authors.affiliation: All authors: Mayo Clinic, Rochester, MN.
authors.forename: Elizabeth B
authors.initials: EB
authors.lastname: Habermann
authors.affiliation: All authors: Mayo Clinic, Rochester, MN.
authors.forename: Sara J
authors.initials: SJ
authors.lastname: Holton
authors.affiliation: All authors: Mayo Clinic, Rochester, MN.
authors.forename: David R
authors.initials: DR
authors.lastname: Holmes
mesh_terms: D000368:Aged; D002173:Cancer Care Facilities / Q000706:statistics & numerical data*; D005260:Female; D061847:Hospitals, High-Volume / Q000706:statistics & numerical data*; D006801:Humans; D008297:Male; D008875:Middle Aged; D009101:Multiple Myeloma / Q000401:mortality* / Q000628:therapy*; D016016:Proportional Hazards Models; D016019:Survival Analysis; D014481:United States / Q000453:epidemiology