Table 1.
Characteristics of Infective Endocarditis Hospitalizations in the United States among Individuals Ages 18–64 Between 1 January 2010, and 31 August 2015
| Full Cohort | IDU | Non-IDU | P Valuea | |||||
|---|---|---|---|---|---|---|---|---|
| n = 30 892 | n = 7259 | n = 23 633 | ||||||
| Weighted n = 153 616 | SEb | Weighted n = 36 133 | SE | Weighted n = 117 482 | SE | |||
| Age | <.0001 | |||||||
| 18–24 | 5.3%c | 0.2 | 10.8% | 0.4 | 3.6% | 0.1 | ||
| 25–34 | 14.9% | 0.2 | 31.8% | 0.6 | 9.7% | 0.2 | ||
| 35–44 | 15.8% | 0.2 | 21.1% | 0.5 | 14.2% | 0.2 | ||
| 45–55 | 27.2% | 0.3 | 22.6% | 0.6 | 28.6% | 0.3 | ||
| 56–65 | 36.8% | 0.3 | 13.8% | 0.5 | 43.8% | 0.4 | ||
| Female | 41.6% | 0.3 | 43.3% | 0.6 | 41.1% | 0.4 | .0017 | |
| Race/ethnicity | <.0001 | |||||||
| White | 64.2% | 0.5 | 72.3% | 0.8 | 61.8% | 0.6 | ||
| Black | 21.0% | 0.4 | 14.9% | 0.6 | 22.9% | 0.5 | ||
| Hispanic | 9.5% | 0.3 | 9.1% | 0.5 | 9.6% | 0.3 | ||
| Asian | 1.8% | 0.1 | 0.6% | 0.1 | 2.1% | 0.1 | ||
| Native American | 0.7% | 0.1 | 0.8% | 0.1 | 0.7% | 0.1 | ||
| Other | 2.8% | 0.2 | 2.3% | 0.2 | 2.9% | 0.2 | ||
| Payor | <.0001 | |||||||
| Medicare | 27.5% | 0.3 | 14.4% | 0.5 | 31.6% | 0.4 | ||
| Medicaid | 27.4% | 0.4 | 45.9% | 0.7 | 21.8% | 0.4 | ||
| Commercial | 29.9% | 0.4 | 13.1% | 0.4 | 35.1% | 0.4 | ||
| Self | 10.3% | 0.3 | 19.9% | 0.6 | 7.3% | 0.2 | ||
| No charge | 1.2% | 0.1 | 2.4% | 0.2 | 0.8% | 0.1 | ||
| Other | 3.7% | 0.2 | 4.3% | 0.3 | 3.5% | 0.2 | ||
| ZIP code income quartile d | <.0001 | |||||||
| Quartile 1 | 37.6% | 0.5 | 42.2% | 0.8 | 36.2% | 0.5 | ||
| Quartile 2 | 25.2% | 0.3 | 25.6% | 0.6 | 25.0% | 0.4 | ||
| Quartile 3 | 20.8% | 0.3 | 19.1% | 0.5 | 21.4% | 0.4 | ||
| Quartile 4 | 16.4% | 0.4 | 13.1% | 0.5 | 17.5% | 0.5 | ||
| Hospital region | <.0001 | |||||||
| Northeast | 19.9% | 0.6 | 20.0% | 0.8 | 19.9% | 0.7 | ||
| Midwest | 17.3% | 0.6 | 14.2% | 0.7 | 18.3% | 0.6 | ||
| South | 42.8% | 0.7 | 42.3% | 1.0 | 43.0% | 0.7 | ||
| West | 19.9% | 0.5 | 23.5% | 0.8 | 18.8% | 0.5 | ||
| Hospital location/teaching status | .0108 | |||||||
| Rural | 7.0% | 0.3 | 6.1% | 0.4 | 7.3% | 0.3 | ||
| Urban, nonteaching | 29.1% | 0.6 | 28.4% | 0.8 | 29.3% | 0.6 | ||
| Urban, teaching | 63.9% | 0.6 | 65.5% | 0.9 | 63.4% | 0.7 | ||
| Hospital bed size | .6676 | |||||||
| Small | 11.0% | 0.2 | 11.1% | 0.5 | 10.9% | 0.3 | ||
| Medium | 24.0% | 0.5 | 24.4% | 0.8 | 23.9% | 0.5 | ||
| Large | 65.0% | 0.6 | 64.5% | 0.9 | 65.2% | 0.6 | ||
| Modified Elixhauser score e | <.0001 | |||||||
| 0 | 2.6% | 0.1 | 4.0% | 0.2 | 2.1% | 0.1 | ||
| 1–2 | 22.3% | 0.3 | 29.0% | 0.6 | 20.2% | 0.4 | ||
| 3–4 | 34.7% | 0.3 | 35.2% | 0.6 | 34.5% | 0.3 | ||
| ≥5 | 40.5% | 0.4 | 31.8% | 0.6 | 43.1% | 0.5 | ||
| Alcohol | 7.5% | 0.2 | 12.4% | 0.4 | 6.0% | 0.2 | <.0001 | |
| Cannabis | 2.3% | 0.1 | 6.1% | 0.3 | 1.1% | 0.1 | <.0001 | |
| Sedatives | 0.5% | 0.04 | 1.8% | 0.2 | 0.1% | 0.01 | <.0001 | |
| Psychoses | 7.3% | 0.2 | 12.6% | 0.4 | 5.7% | 0.2 | <.0001 | |
| Depression | 11.7% | 0.2 | 14.5% | 0.4 | 10.8% | 0.2 | <.0001 | |
| Elective admission | 11.8% | 0.3 | 7.3% | 0.4 | 13.2% | 0.3 | <.0001 | |
| CT surgery | 12.6% | 0.3 | 11.8% | 0.4 | 12.9% | 0.3 | .0244 | |
| LOS, d | 14.0 | 0.1 | 16.0 | 0.2 | 13.4 | 0.2 | <.0001 | |
| Died during hospitalization f | 9.4% | 0.2 | 7.9% | 0.3 | 9.9% | 0.2 | <.0001 |
Abbreviations: AMA, against medical advice; CT, cardiothoracic; IDU, injection drug use; SE, standard error.
aIDU vs non-IDU; all variables compared using chi-squared analysis except modified Elixhauser, which was compared using a t test.
bStandard error is calculated from weighted sample.
cPercentages reported are estimates for all US hospitalizations based on sample weights.
dOrdered from lowest income quartile to highest income quartile.
eElixhauser score contains 30 components weighted equally and is used to adjust for inpatient comorbidities. We included 26 of these components in the modified Elixhauser. We separated psychoses, depression, and alcohol and drug use because these conditions have been previously associated with AMA discharge and IDU. We excluded measures of drug use overlapping with our IDU measure, and included measures for cannabis and sedative use separately.
fDeath data were missing for 1 individual. Percentage is based on a denominator of 30 891 hospitalizations.