Impact of admission month and hospital teaching status on outcomes in subarachnoid hemorrhage: evidence against the July effect

Clinical article

Restricted access

Object

The authors sought to identify the presence of a “July effect,” a transient increase in adverse outcomes during July, among a cohort of spontaneous subarachnoid hemorrhage (SAH) admissions recorded in the National Inpatient Sample (NIS).

Methods

The discharge status, admission month, patient demographics, treatment parameters, and hospital characteristics among spontaneous SAH admissions were extracted from the 2001–2008 NIS. Multivariate regression was used to determine whether an unfavorable discharge status and/or in-hospital mortality significantly increased in summer months in a pattern suggestive of a July effect. Additional models were generated to assess the impact of hospital teaching status on these outcomes.

Results

Among 57,663,486 hospital admissions from the 2001–2008 NIS, 52,879 cases of spontaneous SAH (ICD-9-CM 430) were treated at teaching (36,914 cases [70%]) and nonteaching (15,965 cases [30%]) facilities. Regression models failed to reveal a July effect for in-hospital mortality (χ2 = 0.75, p = 1.000) or unfavorable discharges (χ2 = 1.69, p = 0.999) among monthly SAH admissions, although they did suggest a significant reduction in these outcomes (in-hospital mortality, OR = 0.89, p < 0.001; unfavorable discharges, OR = 0.88, p < 0.001) among teaching hospitals as compared with nonteaching hospitals after adjustment for disparities in demographic, treatment, and hospital characteristics.

Conclusions

The discharge disposition among SAH admissions within the NIS was not suggestive of a July effect but did reveal that teaching institutions have significantly lower rates of adverse outcomes when compared with nonteaching hospitals. Note, however, that the origins of this difference related to teaching status remain unclear.

Abbreviations used in this paper: df = degrees of freedom; ER = emergency room; NIS = National Inpatient Sample; RR = relative risk; SAH = subarachnoid hemorrhage.
Article Information

Contributor Notes

Address correspondence to: Robert J. McDonald, M.D., Ph.D., Department of Radiology, Mayo Clinic, 200 1st Street SW, Rochester, Minnesota 55905. email: mcdonald.robert@mayo.edu.Please include this information when citing this paper: published online September 23, 2011; DOI: 10.3171/2011.8.JNS11324.
Headings
References
  • 1

    Anderson KLKoval KJSpratt KF: Hip fracture outcome: is there a “July effect”?. Am J Orthop 38:6066112009

  • 2

    Bakaeen FGHuh JLemaire SACoselli JSSansgiry SAtluri PV: The July effect: impact of the beginning of the academic cycle on cardiac surgical outcomes in a cohort of 70,616 patients. Ann Thorac Surg 88:70752009

    • Search Google Scholar
    • Export Citation
  • 3

    Barry WARosenthal GE: Is there a July phenomenon? The effect of July admission on intensive care mortality and length of stay in teaching hospitals. J Gen Intern Med 18:6396452003

    • Search Google Scholar
    • Export Citation
  • 4

    Bederson JBConnolly ES JrBatjer HHDacey RGDion JEDiringer MN: Guidelines for the management of aneurysmal subarachnoid hemorrhage: a statement for healthcare professionals from a special writing group of the Stroke Council, American Heart Association. Stroke 40:99410252009

    • Search Google Scholar
    • Export Citation
  • 5

    Berthelsen CL: Evaluation of coding data quality of the HCUP National Inpatient Sample. Top Health Inf Manage 21:10232000

  • 6

    Birbeck GLZingmond DSCui XVickrey BG: Multispecialty stroke services in California hospitals are associated with reduced mortality. Neurology 66:152715322006

    • Search Google Scholar
    • Export Citation
  • 7

    Caughey AB: The July phenomenon: why don't we see it in obstetrics?. J Perinatol 27:71722007

  • 8

    Claridge JASchulman AMSawyer RGGhezel-Ayagh AYoung JS: The “July phenomenon” and the care of the severely injured patient: fact or fiction?. Surgery 130:3463532001

    • Search Google Scholar
    • Export Citation
  • 9

    Dhaliwal ASChu DDeswal ABozkurt BCoselli JSLemaire SA: The July effect and cardiac surgery: the effect of the beginning of the academic cycle on outcomes. Am J Surg 196:7207252008

    • Search Google Scholar
    • Export Citation
  • 10

    Diringer MN: Management of aneurysmal subarachnoid hemorrhage. Crit Care Med 37:4324402009

  • 11

    Englesbe MJPelletier SJMagee JCGauger PSchifftner THenderson WG: Seasonal variation in surgical outcomes as measured by the American College of Surgeons–National Surgical Quality Improvement Program (ACS-NSQIP). Ann Surg 246:4564652007

    • Search Google Scholar
    • Export Citation
  • 12

    Ford AABateman BTSimpson LLRatan RB: Nationwide data confirms absence of ‘July phenomenon’ in obstetrics: it's safe to deliver in July. J Perinatol 27:73762007

    • Search Google Scholar
    • Export Citation
  • 13

    Garcia SCanoniero MYoung L: The effect of July admission in the process of care of patients with acute cardiovascular conditions. South Med J 102:6026072009

    • Search Google Scholar
    • Export Citation
  • 14

    Highstead RGJohnson LSStreet JH IIITrankiem CTKennedy SOSava JA: July—as good a time as any to be injured. J Trauma 67:108710902009. (Erratum in J Trauma 69:1637 2010)

    • Search Google Scholar
    • Export Citation
  • 15

    Huckman RSBarro JR: Cohort turnover and productivity: the July phenomenon in teaching hospitals. Presented at the annual meeting of the Economics of Population Health: Inaugural Conference of the American Society of Health EconomistsMadison, WI2006. (Abstract) (http://www.allacademic.com/meta/p90940_index.html) [Accessed August 8 2011]

    • Search Google Scholar
    • Export Citation
  • 16

    Inaba KRecinos GTeixeira PGRBarmparas GTalving PSalim A: Complications and death at the start of the new academic year: is there a July phenomenon?. J Trauma 68:19222010

    • Search Google Scholar
    • Export Citation
  • 17

    Kestle JRWCochrane DDDrake JM: Shunt insertion in the summer: is it safe?. J Neurosurg 105:3 Suppl1651682006

  • 18

    Kowalski RGClaassen JKreiter KTBates JEOstapkovich NDConnolly ES: Initial misdiagnosis and outcome after subarachnoid hemorrhage. JAMA 291:8668692004

    • Search Google Scholar
    • Export Citation
  • 19

    Kraus JJMetzler MDCoplin WM: Critical care issues in stroke and subarachnoid hemorrhage. Neurol Res 24:Suppl 1S47S572002

  • 20

    Leder DMPeterson EDRoe MTDeLong ERChen AYOhman EM: The “July Phenomenon” revisited: is the quality of care for patients presenting with acute coronary syndromes affected by house officer inexperience? Insights from CRUSADE. Circulation 113:E818E8192006

    • Search Google Scholar
    • Export Citation
  • 21

    Meguid RABrooke BSPerler BAFreischlag JA: Impact of hospital teaching status on survival from ruptured abdominal aortic aneurysm repair. J Vasc Surg 50:2432502009

    • Search Google Scholar
    • Export Citation
  • 22

    Myles TD: Is there an obstetric July phenomenon?. Obstet Gynecol 102:108010842003

  • 23

    Nicholson WKWitter FPowe NR: Effect of hospital setting and volume on clinical outcomes in women with gestational and type 2 diabetes mellitus. J Womens Health (Larchmt) 18:156715762009

    • Search Google Scholar
    • Export Citation
  • 24

    Orandi BJSharma VUpchurch GRNapolitano LM: Is there a “July phenomenon” in central venous catheter placement?. Crit Care Med 35:Suppl 12A1552007. (Abstract)

    • Search Google Scholar
    • Export Citation
  • 25

    Phillips DPBarker GEC: A July spike in fatal medication errors: a possible effect of new medical residents. J Gen Intern Med 25:7747792010

    • Search Google Scholar
    • Export Citation
  • 26

    Qualls MPallin DJSchuur JD: Parametric versus nonparametric statistical tests: the length of stay example. Acad Emerg Med 17:111311212010

    • Search Google Scholar
    • Export Citation
  • 27

    Rosen DSMacdonald RL: Subarachnoid hemorrhage grading scales: a systematic review. Neurocrit Care 2:1101182005

  • 28

    Schroeppel TJFischer PEMagnotti LJCroce MAFabian TC: The “July phenomenon”: is trauma the exception?. J Am Coll Surg 209:3783842009

    • Search Google Scholar
    • Export Citation
  • 29

    Silverman ATGoldfarb MABaker T: When should a surgical resident call an attending surgeon?. J Surg Educ 65:2062122008

  • 30

    Smith ERButler WEBarker FG II: Is there a “July phenomenon” in pediatric neurosurgery at teaching hospitals?. J Neurosurg 105:3 Suppl1691762006

    • Search Google Scholar
    • Export Citation
  • 31

    Stout CLChapman JRScoglietti VCLong ELVaughn DMAbercrombie CL: “July Effect”: an evaluation of a level I teaching hospital's trauma service seasonal mortality rates. Am Surg 74:8788792008

    • Search Google Scholar
    • Export Citation
  • 32

    Turner PDBramble JDRich EC: Cost of care in academic health centers: the July phenomenon revisited. J Gen Intern Med 15:Suppl 11501512000. (Abstract)

    • Search Google Scholar
    • Export Citation
  • 33

    Yaghoubian Ade Virgilio CChiu VLee SL: “July effect” and appendicitis. J Surg Educ 67:1571602010

  • 34

    Yeaton-Massey ACheng YHandler SGranados JCaughey A: The July phenomenon: does it apply to obstetrics?. Am J Obstet Gynecol 201:Suppl 1S2232009. (Abstract)

    • Search Google Scholar
    • Export Citation
  • 35

    Zimmerman JEShortell SMKnaus WARousseau DMWagner DPGillies RR: Value and cost of teaching hospitals: a prospective, multicenter, inception cohort study. Crit Care Med 21:143214421993

    • Search Google Scholar
    • Export Citation
TrendMD
Cited By
Metrics

Metrics

All Time Past Year Past 30 Days
Abstract Views 189 174 32
Full Text Views 132 58 3
PDF Downloads 76 30 1
EPUB Downloads 0 0 0
PubMed
Google Scholar