title: Do higher hospital-wide nurse staffing levels reduce in-hospital mortality in elderly patients with hip fractures: a pilot study.
abstract: BACKGROUND
  There is increasing recognition that lower nurse staffing levels are associated with higher morbidity and mortality among medical and surgical patients. The degree to which this applies to elderly patients with hip fractures is unclear.
  
  
  OBJECTIVE
  We conducted a pilot study using administrative data as an initial step in investigating the relationship between nurse staffing levels and in-hospital mortality among elderly patients with hip fractures.
  
  
  METHODS
  We retrospectively reviewed administrative data for 13,343 patients 65 years or older with a primary diagnosis of hip fracture admitted to 39 Michigan hospitals between 2003 and 2006. We used logistic regression to calculate the change in predicted probability of in-hospital death conferred by differences in the hospitals' overall number of full-time equivalent registered nursing staff (FTE-RN) per patient day. Regression models controlled for patient age, gender, and comorbid conditions; hospital characteristics including teaching status, hip fracture volume, and income/racial composition of the hospital's zip code; and seasonal influenza.
  
  
  RESULTS
  We found an association between hospital-wide nurse staffing levels and in-hospital mortality among patients with hip fractures. The odds of in-hospital mortality decreased by 0.16 for every additional FTE-RN added per patient day, even after controlling for covariates. This association suggests the absolute risk of mortality increases by 0.35 percentage points for every one unit decrease of FTE-RN per patient day, a 16% increase in the risk of death.
  
  
  CONCLUSIONS
  Decreased hospital-wide nurse staffing levels are associated with increased in-hospital mortality among patients admitted with hip fractures. These observations indicate the need for further studies to characterize this relationship for staffing of units caring for patients with hip fractures.
  
  
  METHODS
  Level III, prognostic study. See Guidelines for Authors for a complete description of levels of evidence.
authors: Department of Orthopaedic Surgery, University of Michigan, 2912 Taubman Center, Ann Arbor, MI 48109-5328, USA. petschil@med.umich.edu
authors: Peter
authors: P
authors: Schilling
authors: James A
authors: JA
authors: Goulet
authors: Paul J
authors: PJ
authors: Dougherty
references: Health Serv Res. 2008 Oct;43(5 Pt 1):1674-92
references: 18459953
references: JAMA. 2002 Oct 23-30;288(16):1987-93
references: 12387650
references: Health Serv Res. 2004 Apr;39(2):279-300
references: 15032955
references: Int Orthop. 2007 Aug;31(4):483-5
references: 16909250
references: J Bone Joint Surg Am. 2002 Apr;84(4):670-4
references: 11940633
references: Injury. 1995 May;26(4):237-40
references: 7649622
references: Br J Anaesth. 2000 Apr;84(4):450-5
references: 10823094
references: J Bone Joint Surg Am. 2008 Jun;90(6):1197-205
references: 18519311
references: Med Care. 1998 Jan;36(1):8-27
references: 9431328
references: Anesthesiology. 2000 Jul;93(1):152-63
references: 10861159
references: J Am Geriatr Soc. 2005 Sep;53(9):1476-82
references: 16137275
references: J Infect Dis. 2000 Mar;181(3):831-7
references: 10720501
references: Am J Public Health. 1997 Oct;87(10):1630-6
references: 9357344
references: Cochrane Database Syst Rev. 2004 Oct 18;(4):CD001704
references: 15495015
references: JAMA. 2004 Apr 14;291(14):1738-43
references: 15082701
references: J Orthop Trauma. 2006 Nov-Dec;20(10):675-9
references: 17106377
references: J Bone Miner Res. 1997 Jan;12(1):24-35
references: 9240722
references: Am J Public Health. 1997 Mar;87(3):398-403
references: 9096540
references: J Bone Joint Surg Br. 1992 Mar;74(2):203-5
references: 1544952
references: J Am Geriatr Soc. 2008 Oct;56(10):1831-8
references: 19054201
references: Injury. 2005 Nov;36(11):1311-5
references: 16214475
references: J Bone Joint Surg Br. 2005 Aug;87(8):1123-6
references: 16049251
references: Cancer. 2005 Sep 1;104(5):975-84
references: 16044400
references: Cochrane Database Syst Rev. 2001;(3):CD000106
references: 11686951
references: J Bone Joint Surg Am. 2002 Apr;84(4):562-72
references: 11940616
references: Health Serv Manage Res. 1999 Nov;12(4):258-68
references: 10622804
references: J Orthop Trauma. 1997 Apr;11(3):162-5
references: 9181497
references: Med Care. 2007 Dec;45(12):1195-204
references: 18007170
references: Qual Saf Health Care. 2002 Sep;11(3):239-45
references: 12486988
references: Cochrane Database Syst Rev. 2004 Oct 18;(4):CD000521
references: 15494999
references: Health Econ. 2005 Jul;14(7):737-53
references: 15744748
references: N Engl J Med. 2002 May 30;346(22):1715-22
references: 12037152
references: J Bone Joint Surg Am. 1987 Dec;69(9):1335-40
references: 3440792
references: J Bone Joint Surg Am. 2008 Jul;90(7):1436-42
references: 18594090
references: J Gen Intern Med. 2005 Nov;20(11):1019-25
references: 16307627
references: J Gerontol. 1990 May;45(3):M101-7
references: 2335719
references: Int Orthop. 2008 Dec;32(6):723-7
references: 17687554
references: J Bone Joint Surg Am. 1995 Oct;77(10):1551-6
references: 7593064