title: Association between adjuvant chemotherapy and risk of acute kidney injury in elderly women diagnosed with early-stage breast cancer.
abstract: We studied elderly Medicare enrollees newly diagnosed with early-stage breast cancer to examine the association between adjuvant chemotherapy and acute kidney injury (AKI).
  
  
  
  Using the linked Surveillance, Epidemiology, and End Results (SEER)-Medicare database, we conducted a retrospective cohort study including women diagnosed with stages I-III breast cancer at ages 66-89 years between 1992 and 2007. We performed one-to-one matching on time-dependent propensity score on the day of adjuvant chemotherapy initiation within 6 months after the first cancer-directed surgery based on the estimated probability of chemotherapy initiation at each day for each patient, using a Cox proportional hazards model. We estimated the cumulative incidence of AKI using Kaplan-Meier methods. We used Cox proportional hazards models to evaluate the association between chemotherapy and the risk of AKI, and compared the risk among major chemotherapy types.
  
  
  
  The study included 28,048 women. The 6-month cumulative incidence of AKI was 0.80% for chemotherapy-treated patients, compared with 0.30% for untreated patients (P < 0.001). Adjuvant chemotherapy was associated with a nearly threefold increased risk of AKI [hazard ratio (HR) 2.73; 95% CI 1.8-4.1]. Compared with anthracycline-based chemotherapy, the HRs (95% CIs) were 1.66 (0.94-2.91), 0.88 (0.53-1.47), and 1.15 (0.57-2.32) for taxane-based, CMF, and other chemotherapy, respectively.
  
  
  
  Our findings showed that adjuvant chemotherapy was associated with increased risk of AKI in elderly women diagnosed with early-stage breast cancer. The risk seemed to vary by regimen type, but the differences were not statistically significant.
authors.affiliation: Chronic Disease Research Group, Minneapolis Medical Research Foundation, 914 South 8th Street, Suite S2.100, Minneapolis, MN, 55404, USA. slli@cdrg.org.
authors.forename: Shuling
authors.initials: S
authors.lastname: Li
authors.affiliation: Chronic Disease Research Group, Minneapolis Medical Research Foundation, 914 South 8th Street, Suite S2.100, Minneapolis, MN, 55404, USA.
authors.forename: Jiannong
authors.initials: J
authors.lastname: Liu
authors.affiliation: Division of Health Services Research and Policy, School of Public Health, University of Minnesota, Minneapolis, MN, USA.
authors.forename: Beth A
authors.initials: BA
authors.lastname: Virnig
authors.affiliation: Chronic Disease Research Group, Minneapolis Medical Research Foundation, 914 South 8th Street, Suite S2.100, Minneapolis, MN, 55404, USA.|Department of Medicine, University of Minnesota, Minneapolis, MN, USA.
authors.forename: Allan J
authors.initials: AJ
authors.lastname: Collins
mesh_terms: D058186:Acute Kidney Injury / Q000453:epidemiology* / Q000209:etiology*; D000367:Age Factors; D000368:Aged; D000369:Aged, 80 and over; D000971:Antineoplastic Combined Chemotherapy Protocols / Q000009:adverse effects* / Q000627:therapeutic use; D001943:Breast Neoplasms / Q000150:complications* / Q000175:diagnosis / Q000188:drug therapy / Q000453:epidemiology*; D017024:Chemotherapy, Adjuvant / Q000009:adverse effects; D015897:Comorbidity; D005260:Female; D005500:Follow-Up Studies; D006801:Humans; D015994:Incidence; D008207:Lymphatic Metastasis; D006278:Medicare; D060787:Neoplasm Grading; D009367:Neoplasm Staging; D012306:Risk; D018426:SEER Program; D014481:United States / Q000453:epidemiology
keywords: Acute kidney injury; Adjuvant chemotherapy; Breast cancer; Medicare