title: A population-based study on the association between acute renal failure (ARF) and the duration of polypharmacy.
abstract: BACKGROUND
  Because of the rapid growth in elderly population, polypharmacy has become a serious public health issue worldwide. Although acute renal failure (ARF) is one negative consequence of polypharmacy, the association between the duration of polypharmacy and ARF remains unclear. We therefore assessed this association using a population-based database.
  
  
  METHODS
  Data were collected from the Taiwan National Health Insurance Research Database (NHIRD) from 2003 through 2006. The case group included patients hospitalized for ARF during 2006, but not admitted due to trauma, surgery, burn trauma, car accident, transplantation, or infectious diseases; the control group included patients hospitalized without ARF. The cumulative number of days of polypharmacy (defined as more than 5 prescriptions per day) for 1 year prior to admission was determined, with patients further subdivided into 4 categories: less than 30 days, 31-90 days, 91-180 days, and over 181 days. The dependent variable was ARF, and the control variables were age, gender, comorbidities in patients hospitalized for ARF, stay in ICUs during ARF hospitalization and site of operation for prior admissions within one month of ARF hospitalization.
  
  
  RESULTS
  Of 20,790 patients who were admitted to hospitals for ARF in 2006, 12,314 (59.23 %) were male and more than 60 % were older than 65 years. Of patients with and without ARF, 16.14 % and 10.61 %, respectively, received polypharmacy for 91-180 days and 50.22 % and 24.12 %, respectively, for over 181 days. A statistical model indicated that, relative to patients who received polypharmacy for less than 30 days, those who received polypharmacy for 31-90, 91-180 and over 181 days had odds ratios of developing ARF of 1.33 (p<0.001), 1.65 (p<0.001) and 1.74 (p<0.001), respectively.
  
  
  CONCLUSIONS
  We observed statistically significant associations between the duration of polypharmacy and the occurrence of ARF.
authors.affiliation: Department of Nephrology, Taoyuan Veterans Hospital, 100 Cheng Kong Rd, Sec. 3, Taoyuan City 33010, Taiwan.
authors.forename: Yi-Ping
authors.initials: YP
authors.lastname: Chang
authors.forename: San-Kuei
authors.initials: SK
authors.lastname: Huang
authors.forename: Ping
authors.initials: P
authors.lastname: Tao
authors.forename: Ching-Wen
authors.initials: CW
authors.lastname: Chien
mesh_terms: D058186:Acute Kidney Injury / Q000139:chemically induced* / Q000175:diagnosis / Q000453:epidemiology*; D000293:Adolescent; D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D016022:Case-Control Studies; D002648:Child; D002675:Child, Preschool; D064420:Drug-Related Side Effects and Adverse Reactions; D005260:Female; D006760:Hospitalization / Q000639:trends; D006801:Humans; D007223:Infant; D007231:Infant, Newborn; D007344:Insurance Claim Reporting / Q000639:trends; D008297:Male; D008875:Middle Aged; D019338:Polypharmacy; D011159:Population Surveillance / Q000379:methods; D012189:Retrospective Studies; D013997:Time Factors; D055815:Young Adult