title: Acute pyelonephritis in US hospitals in 1997: hospitalization and in-hospital mortality.
abstract: OBJECTIVE
  To describe the 1997 incidence of hospitalization for acute pyelonephritis in the US and the risk factors for in-hospital mortality associated with acute pyelonephritis.
  
  
  METHODS
  Cases were defined as those with ICD9-CM codes corresponding to acute pyelonephritis in the 1997 Health Care Cost and Utilization Project (HCUP) Nationwide Inpatient Sample (NIS). Frequencies and calculations were weighted to produce either national or state estimates. Hospitalization rates were calculated using 1997 US Census Bureau population projections for the denominator.
  
  
  RESULTS
  Females were almost five times as likely as males to be hospitalized for acute pyelonephritis (11.7/10,000 vs. 2.4/10,000), but males had higher mortality rates (16.5/1000 vs. 7.3/1000); 30% greater after adjustment. Hospitalization and in-hospital mortality rates increased with age, but not with diabetes. Mortality rates increased with number of procedures, diagnoses and having a major diagnostic category other than disorders of the kidney and urinary tract. Persons living in zip codes with lower median incomes were also at higher risk of mortality. There was little variation in mortality by hospital size, ownership, location or teaching status.
  
  
  CONCLUSIONS
  In hospital mortality for pyelonephritis was associated with patient rather than hospital characteristics suggesting uniform application of standard care across hospitals and populations.
authors.affiliation: University of Michigan, School of Public Health, Department of Epidemiology, 109 Observatory Street, Ann Arbor 48109-2029, USA. bfoxman@umich.edu
authors.forename: Betsy
authors.initials: B
authors.lastname: Foxman
authors.forename: Kelly L
authors.initials: KL
authors.lastname: Klemstine
authors.forename: Patricia D
authors.initials: PD
authors.lastname: Brown
mesh_terms: D000208:Acute Disease; D000293:Adolescent; D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D002648:Child; D015897:Comorbidity; D005260:Female; D017052:Hospital Mortality; D006760:Hospitalization / Q000706:statistics & numerical data*; D006801:Humans; D008297:Male; D008875:Middle Aged; D011704:Pyelonephritis / Q000453:epidemiology / Q000401:mortality*; D014481:United States / Q000453:epidemiology