title: Is Shock Index a Valid Predictor of Mortality in Emergency Department Patients With Hypertension, Diabetes, High Age, or Receipt of β- or Calcium Channel Blockers?
abstract: OBJECTIVE
  Shock index is a widely reported tool to identify patients at risk for circulatory collapse. We hypothesize that old age, diabetes, hypertension, and β- or calcium channel blockers weaken the association between shock index and mortality.
  
  
  METHODS
  This was a cohort study of all first-time emergency department (ED) visits between 1995 and 2011 (n=111,019). We examined whether age 65 years or older, diabetes, hypertension, and use of β- or calcium channel blockers modified the association between shock index and 30-day mortality.
  
  
  RESULTS
  The 30-day mortality was 3.0%. For all patients, with shock index less than 0.7 as reference, a shock index of 0.7 to 1 had an adjusted odds ratio (OR) of 2.9 (95% confidence interval [CI] 2.7 to 3.2) for 30-day mortality, whereas shock index greater than or equal to 1 had an OR of 10.5 (95% CI 9.3 to 11.7). The crude OR for shock index greater than or equal to 1 in patients aged 65 years or older was 8.2 (95% CI 7.2 to 9.4) compared with 18.9 (95% CI 15.6 to 23.0) in younger patients. β- Or calcium channel-blocked patients had an OR of 6.4 (95% CI 4.9 to 8.3) versus 12.3 (95% CI 11.0 to 13.8) in nonusers and hypertensive patients had an OR of 8.0 (95% CI 6.6 to 9.4) versus 12.9 (95% CI 11.1 to 14.9) in normotensive patients. Diabetic patients had an OR of 9.3 (95% CI 6.7 to 12.9) versus 10.8 (95% CI 9.6 to 12.0) in nondiabetic patients. A shock index of 0.7 to 1 was associated with ORs greater than 1 (range 2.2 to 3.1), with no evident differences within subgroups. The adjusted analyses showed similar ORs.
  
  
  CONCLUSIONS
  Shock index is independently associated with 30-day mortality in a broad population of ED patients. Old age, hypertension, and β- or calcium channel blockers weaken this association. However, a shock index greater than or equal to 1 suggests substantial 30-day mortality risk in all ED patients.
authors.affiliation: Department of Emergency Medicine, Odense University Hospital, Odense, Denmark; Department of Emergency Medicine, Beth Israel Deaconess Medical Center and Harvard Medical School, Boston, MA. Electronic address: anders.bruun.kristensen@rsyd.dk.
authors.forename: Anders K B
authors.initials: AK
authors.lastname: Kristensen
authors.affiliation: Department of Emergency Medicine, Odense University Hospital, Odense, Denmark.
authors.forename: Jon G
authors.initials: JG
authors.lastname: Holler
authors.affiliation: Clinical Pharmacology, Institute of Public Health, University of Southern Denmark, Odense, Denmark.
authors.forename: Jesper
authors.initials: J
authors.lastname: Hallas
authors.affiliation: Department of Emergency Medicine, Odense University Hospital, Odense, Denmark.
authors.forename: Annmarie
authors.initials: A
authors.lastname: Lassen
authors.affiliation: Department of Emergency Medicine, Beth Israel Deaconess Medical Center and Harvard Medical School, Boston, MA.
authors.forename: Nathan I
authors.initials: NI
authors.lastname: Shapiro
mesh_terms: D000319:Adrenergic beta-Antagonists / Q000009:adverse effects*; D000367:Age Factors; D000368:Aged; D000369:Aged, 80 and over; D002121:Calcium Channel Blockers / Q000009:adverse effects*; D003718:Denmark / Q000453:epidemiology; D003920:Diabetes Mellitus / Q000401:mortality*; D004636:Emergency Service, Hospital; D005260:Female; D006801:Humans; D006973:Hypertension / Q000401:mortality*; D008297:Male; D011237:Predictive Value of Tests; D012189:Retrospective Studies; D012720:Severity of Illness Index; D012769:Shock / Q000401:mortality* / Q000503:physiopathology*
chemical_list: D000319:Adrenergic beta-Antagonists; D002121:Calcium Channel Blockers